I went and read your postings in the engine section. I am wondering what your true compression ratio is with the custom pistons and the .050"-milled head. What kind of exhaust manifold or header are you using?
From what I hear (no real-world experience on this,) a wider lobe separation, up to 116-degrees is good for turbo motors. Reduces overlap...
My racing partner and I are building a turbo'd slant 6 that is a virtual clone of Tom Wolfe's (Shaker223) motor, with some minimal differences.
One mistake we made was in not O-Ringing the motor. Try not to make that mistake... I am pretty sure that not doing that will come back to bite us when we try to go to some meaningful boost levels. Lots easier to do it now, while your engine is apart, than later.... much more work, then.
The Buick 3.8-liter V6 is somewhat different from a /6, but has more similarities than differences, I think. I go to breakfast on Saturdays with 6-8 of those guys and they share their stories with me, some of which are pertinent to my motor, and some are not.
They only run 208-210 degrees duration cams at .050"-lift. Their engines have slightly bigger valves, but still are rpm limited (by the drivers) to about 5,500. Most of the Grand Nationals weigh about 3,400+ pounds and most of their cars run low 11's, with a few in the mid-10's, with 20-25 pounds of boost. More than that and they seem not to live very long... lol!
Your car will be 600-800 pounds lighter, probably. That's a bunch...
Mark Ethridge's early Valiant only weighs about 2,350, I think. But, he has worked at it... Great racer, that guy...
Our car is a '64, but has no rear seat, a fiberglass hood, no front bumper (intercooler took care of that) and lightweight buckets. We are hoping for a race-weight of maybe 2,700 pounds without driver. We did add subframe connectors aand a roll bar, so our car may be a little heaver than we'd hoped...
Our engine is together, but we still have a few time-consuming things to do on our car before it's ready for action; an entire fuel supply system (we have all the parts) and some relay and pump wiring, and gauges.
Aaron (Turbo Toad) has a car very much like yours, and is in the final construction phase, and there are probably more (turbo slants) being built, that I am unaware of. Ryan Peterson's '66 Valiant is am absoulte KILLER at 127 mph... (and that's with a 727!)
This is exciting!!!!
Thanks for your response! Good luck with your build!!!
Bill in Conway, Arkansas