Anyone know what the specs are on the stock lo3 tbi heads?

 

Boat Anchor

 

Something tells me that wasnt the answer he was looking for.

 

1.84/1.50 intake valves. 58cc chambers.

The really "unique" feature of the heads is that the intake port just behind the intake valve head is like half a spiral staircase. It's the infamous "swirl ramp" and that's almost exactly what it looks like. Great for inducing swirl to the incoming mixture, but not so great for flow.

Remember, it was GM's first attempt and a swirl-inducing port design for the small block Chevy. Later Vortec heads are also good at inducing swirl to the incoming mixture, but they flow like niagara falls in the process.

 

Yeah, I know - but I just couldn't resist!

 

Thanks for the help, I'm a 3rd gen newbie and doing a budget mod, trying to gain some horsies without having to have ecm work done!

 

Best bang for your buck is a 350 swap, using a 350 TBI computer prom, knock sensor, and injectors from a Caprice or truck.

Heads are dangerous territory on the 305. A couple folks have done some porting to the swirl port heads, but I don't know flow numbers. I swapped mine for #416 heads years ago, added LT1 cam, intake, headers ... never got a good chip tuned for it after months of datalogging.

You can do exhaust, LT1 cam, free TBI mods (do a ), and that about is the limit for the stock chip. Rear gears will make it all "feel" better, but in the end you'll never break 200hp without a custom chip tune on the 305 motor.