302 to 390
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302 to 390
i have a 72 w/ a 302 i would like a 390 i have a smallblock c6 will a big block c6 bolt in the same place exactly? if so when i change the motor mounts for a 390 will everything line up correctly the motor to tranny from tranny to rearend/driveshaft?
Postmaster
Joined: Apr 2002
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From: Coal country
No, nothing will interchange between the 302 and the 390. Make sure you get a C-6 for an FE. There is no such thing as "Ford Big Block" - there are several engines that have that term applied, but nothing between them interchanges.
Fortunately, the frame is pre-drilled for a variety of setups, so you shouldn't have any problem putting a 390 setup into your truck. If you get the right setup, everything will bolt up. You just have to make sure you get everything.
I changed out the 352 /3 speed in my '66 F-100 to a 460 /C-6 from a '77 F-250 and everything bolted right up. Looks factory, too. I had a donor truck to work with, and that made it a lot easier.
Look for parts from a '68 - '76 F-100 to F-250 with a 360 or 390 and a C-6. Everything from a 360 will bolt to a 390. Ford quit putting FEs into trucks in '76, but other parts like steering columns and so forth will still interchange.
That 390 is a great choice, though, and will be worth the work.
Fortunately, the frame is pre-drilled for a variety of setups, so you shouldn't have any problem putting a 390 setup into your truck. If you get the right setup, everything will bolt up. You just have to make sure you get everything.
I changed out the 352 /3 speed in my '66 F-100 to a 460 /C-6 from a '77 F-250 and everything bolted right up. Looks factory, too. I had a donor truck to work with, and that made it a lot easier.
Look for parts from a '68 - '76 F-100 to F-250 with a 360 or 390 and a C-6. Everything from a 360 will bolt to a 390. Ford quit putting FEs into trucks in '76, but other parts like steering columns and so forth will still interchange.
That 390 is a great choice, though, and will be worth the work.
Last edited by banjopicker66; Apr 13, 2006 at 04:09 AM.
Postmaster
Joined: Apr 2002
Posts: 3,613
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From: Coal country
That is a distinct possibility, as the Ford 3.03 3 speed was common in Ford trucks for many years, behind all the engines they used.
Now behind a 390, the extra torque may tear it up. It was used behind 352 FEs, but it may not stand up behind a 390, unless you go gently on it.
One thing to check is the input shaft length and size. It may very well be different for a 302 than an FE.
Now behind a 390, the extra torque may tear it up. It was used behind 352 FEs, but it may not stand up behind a 390, unless you go gently on it.
One thing to check is the input shaft length and size. It may very well be different for a 302 than an FE.
Posting Guru
Joined: Jul 2003
Posts: 2,222
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From: East Central Florida
I concur 100% with BP66.
Especially the part about breaking a tranny. It doesn't have adequate thrust washers or internal bearings for big torque. It only has medium duty gears w/smaller teeth etc.
Make sure you got a supply of clusters & 1stX Rev slider gears & tranny gaskets. For My $.02 why put a bigger engine in you can't really use with older style 3 gear manual tranny?
FBp
Especially the part about breaking a tranny. It doesn't have adequate thrust washers or internal bearings for big torque. It only has medium duty gears w/smaller teeth etc.
Make sure you got a supply of clusters & 1stX Rev slider gears & tranny gaskets. For My $.02 why put a bigger engine in you can't really use with older style 3 gear manual tranny?
FBp
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Joined: Jul 2005
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Will need engine perches for a 390.
Exhaust pipes will need to be redone.
crossmember will need to be move back with the bigger C6.
The engine and transmission will need to be mated, then you will need to determine where the engine perches (towers) and crossmember fit best.
The drive shaft will need to be shorthen at a machine shop and balanced.
It takes some time to do this conversion, but the time spent is well worth it.
Exhaust pipes will need to be redone.
crossmember will need to be move back with the bigger C6.
The engine and transmission will need to be mated, then you will need to determine where the engine perches (towers) and crossmember fit best.
The drive shaft will need to be shorthen at a machine shop and balanced.
It takes some time to do this conversion, but the time spent is well worth it.
