[gabnmantha]

Hi guys, I finally have my 68 GT390 4spd FB in my garage! It's finally home. I'd like some thoughts & opinions on upgrades. It has a 4bbl Holley and an Edlebrock alum. manifold. Other than that it is all stock from quality engine rebuild about 2000 miles ago. I plan on installing a new exhaust w/ either flowasters or magnaflow mufflers.
questions:
Headers? y/n?

Edlebrock performance heads y/n?

Currently running a 3:00 .1 gear. 3:50-3:73 gear y/n?

I was thinkn about doing the exhaust & gear now & possibly the heads & headers this fall.

Opinions?
Regards, Dave

[mr ford]

IMHO, long tube hooker super comps headers with Flowmasters are the setup for these cars..Sounds Bad A%#. 3:73 would be an all around good gear anything more you wouldn't like it on a road trip very much, plus old big blocks were not made to rev very high for long periods....The hot ticket was to put on 428 cj heads and dump the stock 390's.. Are the elderbrock 428 style?? And yes I still miss playing with my old 67 390 gt 4spd fstback. I'll have to scan a picture of the old girl and you'll see what I mean..

This post has been edited by mr ford: 23 April 2008 - 01:48 PM

[gabnmantha]

mr ford, on Apr 23 2008, 03:46 PM, said:

IMHO, long tube hooker super comps headers with Flowmasters are the setup for these cars..Sounds Bad A%#. 3:73 would be an all around good gear anything more you wouldn't like it on a road trip very much, plus old big blocks were not made to rev very high for long periods....The hot ticket was to put on 428 cj heads and dump the stock 390's.. Are the elderbrock 428 style?? And yes I still miss playing with my old 67 390 gt 4spd fstback. I'll have to scan a picture of the old girl and you'll see what I mean..

Thanks for the info! Love to see your "old girl"!

[fastfords]

I may be overstating the obvious. It's important to maximize potential from what you do have. Have a "old school" speed shop recurve the distributor to match the camshaft specs. Most times people install a rebuilt distributor with no idea how the centrifugal advance springs are set and the odds of it matching your cam are almost nil. I also like to replace the points and condenser set up with an ignitor. If the dwell angle is off even a little it will cost you power. Short of building the motor with higher compression and a more agressive cam there is only so much you will be able to get out of it. If you can afford them I have heard good things about the Edelbrock aluminum heads and they also save weight as well. Don't believe the crap about a 390 not running very well. If you want max power, find a vintage 735 holley off a 428 car and have it restored. The reason 390's ran out of steam above 4500 rpm is the tiny 4v they had on them. My last S code Mach 1 had a 9.5:1 390GT motor with a Ford Motorsport cam and a C9AF-U 4v on it. Ran like a scalded dog with the ignitor and the recurved dist. Stock rims and tires, C6 with 3.50 trak-lok and my buddy's 69' Mach with a very healthy 351C/4-speed/4.56 spool could not walk away from me. Dead even until we shut down at the top of second gear for me. His car had run 12.99 before with sticky tires. Those were the good old days. Enjoy.

[gabnmantha]

fastfords, on May 2 2008, 06:23 PM, said:

I may be overstating the obvious. It's important to maximize potential from what you do have. Have a "old school" speed shop recurve the distributor to match the camshaft specs. Most times people install a rebuilt distributor with no idea how the centrifugal advance springs are set and the odds of it matching your cam are almost nil. I also like to replace the points and condenser set up with an ignitor. If the dwell angle is off even a little it will cost you power. Short of building the motor with higher compression and a more agressive cam there is only so much you will be able to get out of it. If you can afford them I have heard good things about the Edelbrock aluminum heads and they also save weight as well. Don't believe the crap about a 390 not running very well. If you want max power, find a vintage 735 holley off a 428 car and have it restored. The reason 390's ran out of steam above 4500 rpm is the tiny 4v they had on them. My last S code Mach 1 had a 9.5:1 390GT motor with a Ford Motorsport cam and a C9AF-U 4v on it. Ran like a scalded dog with the ignitor and the recurved dist. Stock rims and tires, C6 with 3.50 trak-lok and my buddy's 69' Mach with a very healthy 351C/4-speed/4.56 spool could not walk away from me. Dead even until we shut down at the top of second gear for me. His car had run 12.99 before with sticky tires. Those were the good old days. Enjoy.

Thanks for the suggestions. I am currently having the rear end gears switched from the stock 3:00.1 to a 3:70 posi Richmond gears. Next week I plan on adding a new dual exhaust w/ flowmasters. I was gonna go w/ 40 series but am lleaning towards the 50 series flowmasters. There is a new Holley 600 Carb w/ a pertronix coil on the car now. It fires up right away & runs great. The engine really has tons of top end but it needs the new gear set up very badly. I plan on installing a set of edlebrock performer heads a but later this year. I don't want to go too crazy. The engine was rebuilt to factory specs about 2000 miles ago. The compression is about 10-1. Any other thoughts let me know! BTW, here's a pic of both cars before my GT500 was shipped to her new owner

[JAS427]

Hi guys, I finally have my 68 GT390 4spd FB in my garage! It's finally home. I'd like some thoughts & opinions on upgrades. It has a 4bbl Holley and an Edlebrock alum. manifold. Other than that it is all stock from quality engine rebuild about 2000 miles ago. I plan on installing a new exhaust w/ either flowasters or magnaflow mufflers.
questions:
Headers? y/n?

Edlebrock performance heads y/n?

Currently running a 3:00 .1 gear. 3:50-3:73 gear y/n?

I was thinkn about doing the exhaust & gear now & possibly the heads & headers this fall.

Opinions?
Regards, Dave

Hi Dave
I think you really need to decide on what you want as far as driver or Saturday night cruiser and drag strip car. If you want to go drag racing and spin the motor 6000 to 6200 is right where the FE likes to live. A driver likes 5200 to 5600. Once yo decide on the use then you can go in that direction. I have always tryed to keep my cars as drivers but fast ones. Your single biggest improvement will be exhaust. I won't go any bigger then the hooker 6114s there 1 3/4 the 2 1/4 are to hard to work around. Keith Kraft really knows his FEs and can help you on cam and heads. Here are a couple of vides of 2 of my fe cars. The Mustang has 3.5 gear and a smooth idle hyd cam and CJ exhaust manifolds through the factory exhaust. Pm me if you want any builds I have done that work. Hope you like the videos.

http://www.youtube.c...h?v=vFvaBEuV8hw

http://www.youtube.c...h?v=bHJjyqn8W2o

http://www.youtube.c...h?v=6m3xaRXtwaQ

John Strauss

[gabnmantha]

JAS427, on May 3 2008, 06:28 AM, said:

Hi guys, I finally have my 68 GT390 4spd FB in my garage! It's finally home. I'd like some thoughts & opinions on upgrades. It has a 4bbl Holley and an Edlebrock alum. manifold. Other than that it is all stock from quality engine rebuild about 2000 miles ago. I plan on installing a new exhaust w/ either flowasters or magnaflow mufflers.
questions:
Headers? y/n?

Edlebrock performance heads y/n?

Currently running a 3:00 .1 gear. 3:50-3:73 gear y/n?

I was thinkn about doing the exhaust & gear now & possibly the heads & headers this fall.

Opinions?
Regards, Dave

Hi Dave
I think you really need to decide on what you want as far as driver or Saturday night cruiser and drag strip car. If you want to go drag racing and spin the motor 6000 to 6200 is right where the FE likes to live. A driver likes 5200 to 5600. Once yo decide on the use then you can go in that direction. I have always tryed to keep my cars as drivers but fast ones. Your single biggest improvement will be exhaust. I won't go any bigger then the hooker 6114s there 1 3/4 the 2 1/4 are to hard to work around. Keith Kraft really knows his FEs and can help you on cam and heads. Here are a couple of vides of 2 of my fe cars. The Mustang has 3.5 gear and a smooth idle hyd cam and CJ exhaust manifolds through the factory exhaust. Pm me if you want any builds I have done that work. Hope you like the videos.

http://www.youtube.c...h?v=vFvaBEuV8hw

http://www.youtube.c...h?v=bHJjyqn8W2o

http://www.youtube.c...h?v=6m3xaRXtwaQ

John Strauss

Hi John.,
I won't take the car to the strip. I want a car that has a great jump of the line w/ lots of torque. I would like headers but not sure if they are worth the trouble for the average street & show use I will be using it for. That's why I planned on upgrading the exhaust & adding the 3:70 posi. If I need more power I will look into heads & headers later this summer or fall. Finding the right guys to do the work who really know what they are doing is the toughest part too. I have a couple guys I like but they are always very busy. If I took the car in for heads & headers to one of them now I wouldn't get the car back till mid June. So, I will do the mods a little at a time & try to keep it as original as possible while adding as much power as possible...Oh Ya, & still be able to make my house payment!

Regards, Dave

[LuckySnake]

gabnmantha, on May 3 2008, 06:57 AM, said:

Thanks for the suggestions. I am currently having the rear end gears switched from the stock 3:00.1 to a 3:70 posi Richmond gears. Next week I plan on adding a new dual exhaust w/ flowmasters. I was gonna go w/ 40 series but am lleaning towards the 50 series flowmasters. There is a new Holley 600 Carb w/ a pertronix coil on the car now. It fires up right away & runs great. The engine really has tons of top end but it needs the new gear set up very badly. I plan on installing a set of edlebrock performer heads a but later this year. I don't want to go too crazy. The engine was rebuilt to factory specs about 2000 miles ago. The compression is about 10-1. Any other thoughts let me know! BTW, here's a pic of both cars before my GT500 was shipped to her new owner

I'm running a 3.50 gear in my 429CJ, I wouldn't want any taller gear for the street. Good Luck.

[JAS427]

Its great you decided what you want. I would leave the rear gears the way they are and built a little torque monster. These engines are made for that and you don't need that rough idle. I would try to find a set of 428 Cobra Jet mustang maifolds they will work fine for this kind of build. My little GTA coupe has a 428ci engine with Edelbrock heads CJ manifolds a 427 lowriser dual plane manifold and a small hyd smooth idle cam all running out 2 1/4 factory exhaust with 3.5 gears. I wish they were 3.25 or 3.0s just don't need the 3.5 in this set up. Here are a couple of sites to go to to learn a little more and answer any questions you may have. But trust me you have a very good base you should be able to add some bolt ons and have a real road runner. Timing on the FEs is really important to make them run, they like a lot 38 to 40 degs at full rpm but most dist won't give that much so you have to turn up the timing at idle this makes them knock. When you get into that let me know, you want as much timing as not to knock at idle then have it all in by 3000 or sooner if it dosn't knock. Tuning really makes them run. On the intake side I really like the Blue Thunder dual plane its a little tall so you might not be able to use a stock air filter. But the Edebrock RPM works just as good only it has Edelbrock on it. Let me know the look you want out of the engine and I can help you chose the best parts for that job. No one has ever said my GTA is not a stock 390 it looks factory with about 100lbs of steel off the engine. Hope this gets you started. If you post on the FE forum everyone is a wealth of knowledge. Dr. Jay Brown really does his homework you can count on his knowledge. He won the 1st Drag week with his 69 mustang running 428 FE, he also has his own dyno. Good luck keep in touch.

John Strauss

http://www.keithcraft.com/
http://www.network54.com/Forum/74182/

[gabnmantha]

JAS427, on May 4 2008, 08:28 AM, said:

Its great you decided what you want. I would leave the rear gears the way they are and built a little torque monster. These engines are made for that and you don't need that rough idle. I would try to find a set of 428 Cobra Jet mustang maifolds they will work fine for this kind of build. My little GTA coupe has a 428ci engine with Edelbrock heads CJ manifolds a 427 lowriser dual plane manifold and a small hyd smooth idle cam all running out 2 1/4 factory exhaust with 3.5 gears. I wish they were 3.25 or 3.0s just don't need the 3.5 in this set up. Here are a couple of sites to go to to learn a little more and answer any questions you may have. But trust me you have a very good base you should be able to add some bolt ons and have a real road runner. Timing on the FEs is really important to make them run, they like a lot 38 to 40 degs at full rpm but most dist won't give that much so you have to turn up the timing at idle this makes them knock. When you get into that let me know, you want as much timing as not to knock at idle then have it all in by 3000 or sooner if it dosn't knock. Tuning really makes them run. On the intake side I really like the Blue Thunder dual plane its a little tall so you might not be able to use a stock air filter. But the Edebrock RPM works just as good only it has Edelbrock on it. Let me know the look you want out of the engine and I can help you chose the best parts for that job. No one has ever said my GTA is not a stock 390 it looks factory with about 100lbs of steel off the engine. Hope this gets you started. If you post on the FE forum everyone is a wealth of knowledge. Dr. Jay Brown really does his homework you can count on his knowledge. He won the 1st Drag week with his 69 mustang running 428 FE, he also has his own dyno. Good luck keep in touch.

John Strauss

http://www.keithcraft.com/
http://www.network54.com/Forum/74182/

Thanks alot for all the info John. I already had the 3:70 posi installed & will pick it up tonight. I plan on putting on a new exhaust this week. Which flowmasters sound the best on these 390's? I was gonna use 40 series 2 chamber but am leaning towards the 50 series 3 chamber. Which mufflers would you use? Also, what size exhause pipes should I go with? I really want this car to run & sound as good as it looks. I will go deeper with the engine mods as the summer / fall gets nearer. Should I go with Edlebrock alum heads or look for 428 heads? Does edlebrock make a 428 alum head I can put on my 390?
I hope the 3:70 gears aren't too high. I don't ever go on the expressway & only drive the car around town. I just want a ton of low end torque. Believe me, I sold my 08 GT500 to buy this car back from the man I sold it to 5 years ago. Being able to go 80-150 was too easy to do in 08 Shelby. I could have gotten in a lot of trouble with that car!

Thanks for your help John, Regards, Dave

[JAS427]

Thanks alot for all the info John. I already had the 3:70 posi installed & will pick it up tonight. I plan on putting on a new exhaust this week. Which flowmasters sound the best on these 390's? I was gonna use 40 series 2 chamber but am leaning towards the 50 series 3 chamber. Which mufflers would you use? Also, what size exhause pipes should I go with? I really want this car to run & sound as good as it looks. I will go deeper with the engine mods as the summer / fall gets nearer. Should I go with Edlebrock alum heads or look for 428 heads? Does edlebrock make a 428 alum head I can put on my 390?
I hope the 3:70 gears aren't too high. I don't ever go on the expressway & only drive the car around town. I just want a ton of low end torque. Believe me, I sold my 08 GT500 to buy this car back from the man I sold it to 5 years ago. Being able to go 80-150 was too easy to do in 08 Shelby. I could have gotten in a lot of trouble with that car!

Thanks for your help John, Regards, Dave

I have not really kept up with the muffler thing as I have always gone with the best flowing because I run the exhaust out the back. I do have a 3 inch system on a 68 coupe that I got from Pypes Performance with a x pipe. I won't do a exhaust with out a x pipe. The gain is real. The 3.7s are tight thats what I run. If you decide to stay with those you can go up in RPM to 6000 to 6200. Edel brock makes the 428 head with the 16 bolt hole exhaust make sure you get them right the 427 just have the up and down holes won't work with CJ manifolds or some headers. You will need heads as the stock ones don't have harden exhaust seats and will sink into the heads using unlead fuel. Trust me don't try to have someone change them its just not worth it. I would slow down a bit till you know what you want on the exhaust. A good 2 1/2 with a x would be a good system with some open mufflers. Just use which ever flows the most call the exhaust guys and get some info. There are some tests that show how much they all flow. For making things simple I would use all Edebrock Heads and the RPM intake. I would call Scott at Cam Reserach to do a cam and have it run on his machine to break it in. He has done a few hyd and solids for me but mostly rollers for me. Keith craft also does a nice roller hyd cam great for the street thats what I use now in 2 of my cars. The valve train will be next but save that for another time. Sorry to throw so much at you but with so much FE stuff you really need to do your home work. Oh yes the Edelbrock heads fit the 390 no problem. Keep in touch with any questions.

John

http://www.pypesexhaust.com/

http://www.camresearchcorp.com/

[gabnmantha]

JAS427, on May 5 2008, 09:01 AM, said:

Thanks alot for all the info John. I already had the 3:70 posi installed & will pick it up tonight. I plan on putting on a new exhaust this week. Which flowmasters sound the best on these 390's? I was gonna use 40 series 2 chamber but am leaning towards the 50 series 3 chamber. Which mufflers would you use? Also, what size exhause pipes should I go with? I really want this car to run & sound as good as it looks. I will go deeper with the engine mods as the summer / fall gets nearer. Should I go with Edlebrock alum heads or look for 428 heads? Does edlebrock make a 428 alum head I can put on my 390?
I hope the 3:70 gears aren't too high. I don't ever go on the expressway & only drive the car around town. I just want a ton of low end torque. Believe me, I sold my 08 GT500 to buy this car back from the man I sold it to 5 years ago. Being able to go 80-150 was too easy to do in 08 Shelby. I could have gotten in a lot of trouble with that car!

Thanks for your help John, Regards, Dave

I have not really kept up with the muffler thing as I have always gone with the best flowing because I run the exhaust out the back. I do have a 3 inch system on a 68 coupe that I got from Pypes Performance with a x pipe. I won't do a exhaust with out a x pipe. The gain is real. The 3.7s are tight thats what I run. If you decide to stay with those you can go up in RPM to 6000 to 6200. Edel brock makes the 428 head with the 16 bolt hole exhaust make sure you get them right the 427 just have the up and down holes won't work with CJ manifolds or some headers. You will need heads as the stock ones don't have harden exhaust seats and will sink into the heads using unlead fuel. Trust me don't try to have someone change them its just not worth it. I would slow down a bit till you know what you want on the exhaust. A good 2 1/2 with a x would be a good system with some open mufflers. Just use which ever flows the most call the exhaust guys and get some info. There are some tests that show how much they all flow. For making things simple I would use all Edebrock Heads and the RPM intake. I would call Scott at Cam Reserach to do a cam and have it run on his machine to break it in. He has done a few hyd and solids for me but mostly rollers for me. Keith craft also does a nice roller hyd cam great for the street thats what I use now in 2 of my cars. The valve train will be next but save that for another time. Sorry to throw so much at you but with so much FE stuff you really need to do your home work. Oh yes the Edelbrock heads fit the 390 no problem. Keep in touch with any questions.

John

http://www.pypesexhaust.com/

http://www.camresearchcorp.com/

I just got the car back from having the 3:70 posi & new exhaust installed. The car sounds great. I went with 2 chamber mufflers. However, I thought going from a 3:00 to a 3:70 gear would make a huge difference. It made a little difference but not as much as I thought. I will most likely have to change the heads & maybe a cam. What do you think?

[JAS427]

I just got the car back from having the 3:70 posi & new exhaust installed. The car sounds great. I went with 2 chamber mufflers. However, I thought going from a 3:00 to a 3:70 gear would make a huge difference. It made a little difference but not as much as I thought. I will most likely have to change the heads & maybe a cam. What do you think?

Do you have a tach in the car? If not you need one. If so run the car at 2000 in drive with someone n a car next to you to see the correct MPH. Once you get that then we can go from there. The 3.7 should have made a big difference if not the old gears were probably 3.50s. The mph should be 42. If this correct then you will need to build a 5800 to 6000 rpm engine. This is the range I run all my Fes in. If you go to the Edelbrock site they have a complete package cam to heads. It runs pretty good but more can be had with a different cam. Check them out and the dyno power made. What do you have for a carb and intake now? What dist? What torque converter? How does the car run now does it pull hard to 5000 and stop? Need that tach and the seat of your pants to know when it quits pulling. Let me know we can take it 1 step at a time. Tuning it will really make it run. I can show you a few tricks if you tell me more about the engine and carb.

[gabnmantha]

JAS427, on May 8 2008, 08:11 PM, said:

I just got the car back from having the 3:70 posi & new exhaust installed. The car sounds great. I went with 2 chamber mufflers. However, I thought going from a 3:00 to a 3:70 gear would make a huge difference. It made a little difference but not as much as I thought. I will most likely have to change the heads & maybe a cam. What do you think?

Do you have a tach in the car? If not you need one. If so run the car at 2000 in drive with someone n a car next to you to see the correct MPH. Once you get that then we can go from there. The 3.7 should have made a big difference if not the old gears were probably 3.50s. The mph should be 42. If this correct then you will need to build a 5800 to 6000 rpm engine. This is the range I run all my Fes in. If you go to the Edelbrock site they have a complete package cam to heads. It runs pretty good but more can be had with a different cam. Check them out and the dyno power made. What do you have for a carb and intake now? What dist? What torque converter? How does the car run now does it pull hard to 5000 and stop? Need that tach and the seat of your pants to know when it quits pulling. Let me know we can take it 1 step at a time. Tuning it will really make it run. I can show you a few tricks if you tell me more about the engine and carb.

Hi John,
I have a factory tac & it works good. I have to take the car back to the rear end shop so they can install the correct 22 tooth speedo gear. The perv. rear end was a confirmed 3:00-1 gear set up. The original intake is in a box & the car now has an edlebrock performer alum intake & a Holley 600 cfm carb w/ elect. choke. Also the igntion is a pertronix. The car pulls pretty good but not like I had hoped. A friend of mine is Ray Perez from Performance auto in East Chicago, In. His Blue 66 shelby was on the cover of the June 2004 Hemmings muscle machines magazine. He is a very good Ford engine builder. He said he will help add the heads and cam if I choose to do so.
I know these engines need to get the rpms up to produce the best horsepower. I was hoping to not have to change the heads & cam but it looks like from what you have shared with me that it will need to be done.
BTW, the car seems to pull pretty good till around 5k rpm & them flattens out a bit. What do you suggest I do?
Changing the cam & adding edlebrock 428 heads sound ok to you? If I do that, will I need to add a bigger carburator? How about headers?

Tons of fun just beginning! Regards, Dave

[gabnmantha]

BTW, the car is a 4speed

[LuckySnake]

gabnmantha, on May 9 2008, 02:48 PM, said:

Hi John,
I have a factory tac & it works good. I have to take the car back to the rear end shop so they can install the correct 22 tooth speedo gear. The perv. rear end was a confirmed 3:00-1 gear set up. The original intake is in a box & the car now has an edlebrock performer alum intake & a Holley 600 cfm carb w/ elect. choke. Also the igntion is a pertronix. The car pulls pretty good but not like I had hoped. A friend of mine is Ray Perez from Performance auto in East Chicago, In. His Blue 66 shelby was on the cover of the June 2004 Hemmings muscle machines magazine. He is a very good Ford engine builder. He said he will help add the heads and cam if I choose to do so.
I know these engines need to get the rpms up to produce the best horsepower. I was hoping to not have to change the heads & cam but it looks like from what you have shared with me that it will need to be done.
BTW, the car seems to pull pretty good till around 5k rpm & them flattens out a bit. What do you suggest I do?
Changing the cam & adding edlebrock 428 heads sound ok to you? If I do that, will I need to add a bigger carburator? How about headers?

Tons of fun just beginning! Regards, Dave

I have a very nice double pumper that would make a huge performance difference for you, won't hurt your gas mileage to much as long as you aren't in the secondary allot. I believe it's a 730 and the carb has had a few extra machining $ put into it and worked excellent when I took it off my 429, only pulled it to back to original. PM if interested in a good deal.
Installed the Scott Drake performance front springs for 68-73 applications to my 429CJ today, nice improvement.