Hey guys, I've got a set of LT1 aluminum heads from a '97 Z28, and I'm just wondering about the stock specs on these heads? All I know is that they have ~170cc ports, D-port syle exhaust ports, and 53cc angle plug chambers. What I'd like to know is how heavy the stock valve springs are? What are the heads limitted to as far as valve lift w/o machining the guides? Whats the stock valve sizes (don't have the tools handy to measure)? BTW - I know these aren't a bolt-on to a Gen 1 sbc... this is a special project

I don't know the weight of the valve springs, but the valves are 1.940 intake and 1.500 on the exhaust. Your aluminum heads should flow like this:

Intake Exhaust
0.050 42.0 30.0
0.100 72.0 53.0
0.200 129.0 101.0
0.300 180.0 136.0
0.400 213.0 155.0
0.500 214.0 165.0
0.600 215.0 171.0

Hope that helps!

P.S. That's at 28.0 in h20 drop

You don't happen to know the valve lift limit for a stock LT1 head do you?

Yes, its only slightly better than our SBC heads, about .480-.490 lift.