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Looking at heads possibly...

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
Will an stock gt40 EFI lower intake manifold bolt up to just about any head? I was planning to just put the EFI on my stock '72 motor and run it but then I figured I may as well look into heads. I may have a line on some GT40 heads as well. Will GT40 heads bolt onto my old block? I am not looking for a lot of HP but I am looking for some nice torque. I am also looking into a cam change. I will change it to the H.O. firing order since it will be injected. I don't want to spend a lot here. Give me ideas for a head set and cam kit under $800 together!! This is a rock crawler that occasionally see the road and the stock engine is just too weak to push around 36's and 4.11's. The stock engine has been fully rebuilt recently so the bottom end is in good shape and would be worth working with.
 
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broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,342
Yes the intake will bolt up to sotck heads although I believe you have to use the older intake gaskets to prevent coolent leaks. and yes gt40 heads will bolt onto a earlier block. If they are standard gt40 heads I think you will lose some compression as most early 302's have 58cc heads and about 8.3-1 comp ratio stepping up to 64 cc heads would drop the compression to about 7.3-1 not good unless your super or turbo charging it.
A large part of your weakness is trying to turn 36in tires with 4.11 gears. Even a built up engine wont make that much differance.
 
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73bronco

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
Yes the intake will bolt up to sotck heads although I believe you have to use the older intake gaskets to prevent coolent leaks. and yes gt40 heads will bolt onto a earlier block. If they are standard gt40 heads I think you will lose some compression as most early 302's have 58cc heads and about 8.3-1 comp ratio stepping up to 64 cc heads would drop the compression to about 7.3-1 not good unless your super or turbo charging it.
A large part of your weakness is trying to turn 36in tires with 4.11 gears. Even a built up engine wont make that much differance.

Very good to know about the compression deal! May kill the entire thing besides the cam for me! I know the gearing isn't great for the tires but I pushed the same combo around on my last bronco with a built 351w and was VERY happy with it, so I guess any help is good!
 
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73bronco

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
Heads can be milled.

Yeah but that is for more $. Anyone know how much it would cost to mill some stock gt40 heads to about 58cc chambers? I am a cheap a$$ I guess! Plus I really have a hard time letting anyone do any labor for me!
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,342
Not sure what it would cost but you would also need to get the intake milled as well. A 351W has a lot more lowend torque than a 302 that 1/2" more stroke x8 makes a big differance. Gearing is still your best friend but your right its not cheap.
You also have to consider that most mods will move the powerband up higher so gearing becomes even more of a factor.
 
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