Okay guys, I bought a 302 to put in my truck and converted it to efi. The heads use 13 / 16 style spark plugs, which leads me to think it is older. Also how do I tell if it is h.o or not? The truck has way more power than it ever did with the 351. Thanks guys

 

If it has way more power than your 351 ever did, there was something seriously wrong with your 351...

 

1975 is when the SBF engines got the smaller plugs. If you have a 302 that runs better then your 351 then it more than likely been modded. And how did you efi an early block there are some differences that make putting efi on an early block a bit challenging. You sure you don't have another 351.

 

Yes im sure its a 302 by the intakes I put on, and yes the old 351 was worn out but I didn't figure it was as bad as it was, I put a lot of work into the motor to convert it to to efi, had to get all new intakes, timing cover, and all that stuff. My uncle did say this motor did havrr aftermarket pistons in it, and by power I mean the truck can do burn outs for 50 yards without brake stand. I am very pleased with it.

 

Good deal. Did you use a mass air flow efi system. That the only way I know you can run higher performance pistons and cams on an EFI system.

 

assuming the 302 you swapped in was fuel injected to begin with the best thing to look at, aside from casting numbers, is the distributor. 87-91 motors had the TFI module on the distributor, 92-96 the module is on the fender.

 

We need casting numbers(head and block) to have any idea what you have.