Get 78 302 to 9.5:1????

[stang9gt]

I am rebuilding a 78 302 truck motor to put into my bronco...It has been bored 30 over...What cc are the stock heads on these motors??? 56cc??? I am going to get the comp 4x4 cam and I want to get the compression around 9.5:1 or a little better....Also, is it worth switching the motor over to roller cam??? What is needed to do so???

 

[SPEED FREAK]

I would recomend a roller engine with at least e7 heads. To change over you will need the block, cam, lifters, pushrods, crank rods and pistons from the late block. The rest of your accesories should bolt on sans problem. The newer engines are more efficient and tend to have better power curves. I recomend them.

 

[stang9gt]

I would recomend a roller engine with at least e7 heads. To change over you will need the block, cam, lifters, pushrods, crank rods and pistons from the late block. The rest of your accesories should bolt on sans problem. The newer engines are more efficient and tend to have better power curves. I recomend them.

So I can't convert the 78 block over to roller???

 

[dastang2]

yes you can and it is easy. you have d80e heads and they are not even a good boat ancor. chunk them, they got about 68 cc chambers and huge exhaust bumps. i wouldn't even worry about that roller conversion. if you get a good flat tappet cam, you can overcome the power of that roller conversion. but if you wanna do it, all you need to do is get the dogbones,spider bar,lifters and the 2 bolts that hold the spider bar down and drill and tap 2 holes in the lifter valley to bolt the spider down. now you have a choice here. either you use a large base circle cam which is what stock is and put lifter bore extensions on the block or you get a small base circle cam and do nothing with the lifter bores. i would do the small base circle thing. you also need the correct pushrods and the steel dizzy gear from an HO motor also. look for some e7 heads, they flow better and i think they have smaller chambers. i have a set but the need to be redone.

 

[stang9gt]

yes you can and it is easy. you have d80e heads and they are not even a good boat ancor. chunk them, they got about 68 cc chambers and huge exhaust bumps. i wouldn't even worry about that roller conversion. if you get a good flat tappet cam, you can overcome the power of that roller conversion. but if you wanna do it, all you need to do is get the dogbones,spider bar,lifters and the 2 bolts that hold the spider bar down and drill and tap 2 holes in the lifter valley to bolt the spider down. now you have a choice here. either you use a large base circle cam which is what stock is and put lifter bore extensions on the block or you get a small base circle cam and do nothing with the lifter bores. i would do the small base circle thing. you also need the correct pushrods and the steel dizzy gear from an HO motor also. look for some e7 heads, they flow better and i think they have smaller chambers. i have a set but the need to be redone.

Nice, the bronco now has an 86 block in it..I believe it has the e7 heads so I have those already...I got the 78 block for free in my engine class so I had it bored for free....A little higher compression and a nice cam should be nice in the bronco with 35" tires....

 

[dastang2]

remember, you can't use rods, flywheel, or balancer from an 82 and newer 302 since the 78 is a 28 oz imbalance. that is if you are using a 81 and down cranks.

 

[Daggar]

You got an 86 block in the bronco already? Why not rebuild that one? If it's got the stock pistons in it then toss a good set of Trickflows on it and mill it down till you hit 10:1 and call it a day. you say you've got e7 heads on the 86 motor already so either the pistons were knotched for those heads or have been replaced? which?

 

[dastang2]

you could put 289 heads like i am and get close to 11:1 i was told