What is the difference between the heads(valve size), cam, pistons, compression ratio in an 83 302 DSII, 85 302 tfi feedback carb, and an 86 302 with injectors and throttle body. Or where can I find the info.

 

The 85-86 302 have the worst head design that ford ever used. Two different part numbers were used for 85-86. That's when Ford was playing with the HSC, High Swirl Combustion, for fuel economy. They do not breathe well at all. The 87-96 E7TE truck heads are a much better design. In 92 the trucks went to roller cam and lifters. Pistons and compression I can't recall at the moment. EFI was available in 85 as well. The twin port throttle body is good for ~ 500-600 cfm iirc. The EFI intake itself is capable of quite a bit more. There are more head designs that were used on other vehicles like the Explorer, GT40 and GT40P that are even better but require the entire top end to be changed over.

 

The blocks changed for roller lifters around 85-86 or somewhere in that area, and where used in the cars, and I have heard(no direct proof) that the trucks also used the roller lifter blocks, but used regular tappet lifters and not roller lifters, till probably later on like was mentioned.

I also know a 86 302 I got out of a car that was fuel injected had different pistons with narrow rings. They went to a low friction ring design, but you can(I did) put old time pistons in the engine and use regular rings. I don't know if the trucks had any of this or not.

 

Ford Trucks 302 and 351 went to thinner rings on the pistons in 1986 I believe it could of been a little later 89 or 90

 

The car's switched to rollers in 85-ish but I think they used up the non-roller blocks in the trucks. My 89 had a non-roller block. I think I recall hearing that 90-91-ish you could start to find them with flat tappet cams installed but they're roller blocks.

My 89 had the engine replaced under warranty in the summer of 92 and the replacement was just a long block so they swapped everything over. The dealer took 2 weeks to get it done so I was over there a lot bitching and I saw both blocks at different times. The replacement was supposedly a 91 spec engine and it was a roller block but the 89 wasn't. The new engine has a flat tappet cam in it.

They took one of the heads off the old block and it looked like it was never honed, the cylinders were gouged around the bore, not up and down. They kept trying to pin it on me because I was 16 and they said I was hot-rodding and blew the motor and that's why it was burning a quart of oil every 200 miles. Yeah, I had a few choice words for the service manager that day. Think PO'd 16yo with no profanity filter...