Looking to start my turbo build

QYESTIONS:

1. How Big of Valves can I run?
2. Whats the limits on Slant cams?
3. Where do i find boost friendly head gaskets?
4. What ring gap are the turbo cars running?
5. What can i spin the engine to and make good power?
6. Any suggestions on the T5 swap from an Auto?

1. Most guys run some aftermarket oversize valves that are 1.74" on the intake and 1.5" exhaust. I think you can get them on ebay.

2. A turbo slant six cam that works well is a lot like a stock cam because long duration cams that work well in naturally-aspirated engines defeat the forced induction by having both valves open at the same time (called "overlap) letting the boost out the exhaust port. A good turbo cam would have 210-220 degrees duration at .050" lift with about .484" lift and have 115 degrees of lobe separation. Mine came from Bullet cams

3. Felpro makes a good one that has a "fire ring" design that seems to work well in low boost (up to 15 pounds.) Boost beyond that needs O-rings and a copper gasket, to live... Just my opinion.

4. Ring gap, properly adjusted, runs about .022" on the top ring and .024" on the second.

5. Most good-running turbo slant sixes give up the ghost at 5,500rpm... few run well after that. Do not despair; that is a GOOD thing! It means you don't need a roller cam, or heavy (cam-lobe-killing) $$$ valve springs or $$$ roller rockers. The stock rockers work fine, alomng with some shimmed 340 springs. There are at least two 500 horsepower 225 turbo motors I know of that are red-lined at 5,500 rpm.

6. I believe that turbos LIKE automatic transmissions, for a couple of reasons. The automatic changes gears without having the exhaust interrupted, so the compressor turbine doesn't slow down and have to re-spool, and turbos LIKE to have an uninterrupted load against the engine, which is easier to do with an automatic, like in staging the car for a drag race launch. To demonstrate what makes me think that (like a Fuel motor,) turbo slant sixes really like to be "held back," the guys who have experimented at the drag strip with different final drive ratios, have determined that a turbo slant six will turn in better times with a 2.73:1 ratio than something in the 4's, like a 4.56 or 4.88:1. Strange, but true!

Slant sixes have come from the factory with a variety of clutches, but find a setup that will hold the gobs of torque from a boosted slant six is not easy. It can be done, but the problem is severe enough, and the whole manual transmission setup is difficult enough to make me want to say, "Just bolt a well-built 904 behind it and forget all about shifting for yourself." Your turbocharged engine will thank you!
Just my 2-cents...

Good luck with an exciting project!!!