I have a LO3 in my '89 Caprice and am looking at doing some mods. I already have true dual exhaust and a K&N filter. I was looking at Vortech Heads and a TPI conversion. Anyone here do those mods?
Adam

 

If you use vortec heads you are gonna need the base manifold for the tpi to work. That runs about 400. I am planning on doing this to my IROC this summer. They are good bang for the buck heads and flow really well.

Will

 

You'll also need to have the heads milled because you'll be running this on a 305. Otherwise your compression will go in the toilet. She'll drop to around ~8-8.5:1. I wouldn't go that route, but that's just me.

 

They don't make Vortech heads for a 305 anyplace? I don't see why they wouldn't. When you say base manifold, you mean the whole TPI intake manifold correct?

 

No, Vortecs are for any SBC (Gen I). The combustion chambers are just larger than a 305 needs, thus the low compression. They don't need any work done to them to go on a 305. Just be prepared for the compression loss, causing a major HP loss.

Base Manifold, is just the piece that bolts to the heads. Not the runners and not the plenum, just the base.

 

OR, u can get some World S/R Torquer 305 heads and use a factory TPI base, rather than shell out an extra 400 bucks for a Vortec/TPI base......

a much cheaper alternative, and those World heads are MUCH suitable for the 305!!!

 

also need longer spark plug since the stock ones you have will not go all the way into the combustion chamber.

 

I say keep the tbi, its more trouble than its worth swaping to tpi. The power differance between the lo3 and the damnit I forget the rpo for the 305 tpi isn't just in the tpi, so don't expect the same numbers as the tpi moter when you swap. The L03 got lousy heads, as well as other things. I say keep the tbi, and build on the motor you have now, exhaust, ultimate tpi mods, heads cam, and learn to burn chips Or get the L05 from a caprice or chevy truck and that will probably just about bolt up, just a matter of differant injectors, knock sensor and little things like that, that motor isn't great, but when you put headers and an exhaust on it, heads, cam, and get the right chip for it I would think you would have a pretty respectable motor there.