I just bought another 3rd gen and its an 85 model with the TPI 305. I have read that the tach is different between the flat tappet and roller cam cars? (sounds logical) It would seem to me the HP rating of the 85 suggests its a roller cam, but it very well may be a healthy flat tappet. If the tachs are different, mine looks like a roller cam car, yellow at 5000 red at 5500. Thanks for any input.

 

The 1985 car definitely came with a flat tappet cam. I've heard different things about the cam but the engine is more or less an L69 305 H.O. with TPI stuck on it. I've read both that the 85 cam is identical to the L98 flat tappet cam in the Corvette and I've also heard that it is basically the L69 cam. I'm not an authority on cam specifications but I do know that the 1985 cars did in fact use a flat tappet cam.

 

the '85 had a better cam than the later ones, thats where the extra hp came from, but it was still a flat tappet cam. rollers didn't come out untill '87

 

Bummer! Runs good regardless.....for an old 305 that is. I have read so many different answers on this I had no idea what to believe. I wonder why they kept the LB9 designation for two different valvetrain styles.

 

I don't think that's quite true. The later 5 speed TPI 305's with N10 had the L98 cam and were rated for more HP and TQ than the 85 305TPI engine.

 

Mine was flat-tap n less than 400lift