I picked up a Crate SBC for $900 still in the packing from a old guy yesterday and was wondering if there was any advantage to using the Vortec 305 heads would boost my power at all.

The SBC is advertised at 290hp and 326tq.

PS, the SBC is going in a 88 Mazda Rx7

Thanks guys!

 

Most likely they'll help through increased compression and flow.

 

in 1989 there were no vortec heads

 

Oh yea... haha, I think he typo'd in his subject line, I think it's an '89 block, and he wants to put on 305 Vortec heads... (....RIGHT?)

Do you know what heads are on that crate engine? I'd guess 993 heads, but... make sure first..

 

The 305 (5.0L) version of the Vortec heads is not the equal of their larger brother- the 350/5.7L Vortec heads. The 350 Vortec heads are the ones that you hear so much about in the magazines and on the internet.

The 290HP GMPP crate motor uses 993 castings with 1.94/1.50 valves and 76cc chambers. They're pretty crappy by today's standards and they only provide 8.5:1 compression on that motor (which uses -12cc dished pistons).

If 305 Vortec are what you got, then maybe give them a shot. They have mush smaller ~58cc chambers and smaller valves than your current heads (1.84/1.50, I beleive) but they probably flow about the same and the much smaller chambers will get you up to a more reasonable compression ratio in the mid-upper 9s. I bet they will make a little more power and lot more torque than the stock 993s, but that's just a guess.