Originally Posted by 92firebird 305

So i have some questions i have a 350 bord .30 over with a scat crank polished lt1 cam in it 350 tbi heads with new valve springs ported and polish on the heads how much power am i looking at im hoping for over 300 to the tires and 320 tq

Originally Posted by JPrevost

All 87-95 truck and car TBI v8 engines got swirl port heads. Same with the Sy/Ty turbo v6 (LB4 heads). These heads are TERRIBLE for flow, the intake port size is huge at 185cc but they flow less than any other production chevy head! The only good thing about these heads is that the combustion chamber isn't AS pathetic. I can think of at least 4 other heads that have worse chambers but that doesn't make up for the fact that your cylinders are barely filling with air and fuel!
This post should be a sticky where people ONLY post information regarding these heads. No posts about "they aren't that bad" because face it, they are.
The LB4 heads were tested to flow only 165/119 (in/ex) @ .500 lift. To put that into perspective I've attached a graph showing you a couple other heads.
Graph has been updated to show that with porting the heads will flow something more respectable. The intake still falls way short but the exhaust is where the sbc has always needed work. Dyno Don has done his homework and made these heads work rather well. He polished the exhaust port and touched up the intake, look at the flow and his 35+hp gain. Good job Don.

Originally Posted by Ronnie Brennan

what rearend are you running?? is it 10 bolt, 12 bolt? 9 inch? I am in the mid stages of building my 355/700r4 combo. my 700r4 is stock though. also 10 bolt open diff for now. I'm quite nervous of my rearend though. 3.23 gears in it. I plan on babying the car this summer and start horsing around with it towards fall for a stress test. if it lasts I will probably leave it as it is, but still thinking of upgrading rearend with 3.73's and some stuff to strengthen the rear end up.