Anybody know what size valves are in the heads on my 89 TPI 305? Originally automatic trans.

 

All thirdgen 305's have 1.84" intake valves and 1.50" exhaust valves. All thirdgen 350's have 1.94" intake valves and 1.50" exhaust valves.

 

Any benefit to 1.94 intakes on a 305? I was thinking about pulling the heads for a valve job anyway. If they're worn out, might as well go a little bigger, I suppose. My TPI is stock. I've got an LT-1 cam to stick in it when I get the chance. Car has headers.

 

no real gain.
you will run the possibility of PTV clearance problems with the stock head and a real cam.

 

So much for that, then.

Once I get the cam and pro-billet dist in, I'm going to be out of ideas for getting more power from my stock long block.

Roller rockers 2-3 hp maybe. Throttle body bypass might be worth another 2-3.

 

I disagree.

I'm struggling to figure out what "PTV" means, but as long as you unshroud the chambers around the valves, you won't have any clearance problems.

1.94" intakes will help if other things are done as well, such as cam, valve springs, exhaust, runners, porting.

 

PTV is piston-to-valve. Almost no danger of that with stock pistons.

 

Ah.

No danger at all, then.

 

Well if I get the heads off, I'll definitely gasket match and port the pockets, since that's about a freebie, but that's it. Runners...don't think so. That LT-1 conversion manifold seems like a good idea or an HSR, but neither on this 305.

Hadn't thought about springs changing from the ibby dibby 305 auto cam to an LT-1, but I probably should get some.

I don't dislike my 305, but hope that someday it will take a dump so I can replace with a 4" bore. I'm hesitant to spend too much on 305 specific crap. At least 1.94 valves could go to freshen a 350 head...etc, etc.