[N0DIH]

Considering diesels run roughly the same amount of air per revolution (350 CID for a 5.7L, etc), no vacuum in the intake, where a gas engine has a vacuum, so very little, controlled air. You are very correct.

My fear is the cyl pressure will be too high, and you will result in piston breakage and blown head gaskets. I would be very cautious with the rpm at which the boost arrives, hence why I would recommend a slightly larger cam to help bleed off some cyl pressure and a larger turbo so that boost is lagged or delayed until 3500 to 4000 for peak boost to occcur.

Even the famed LT1 can't take more than 6 psi turbo boost, I doubt that Cadillac has better pistons in the 4.9L than the LT1 has.

My advice is boost with caution. Take advice from the diesel 5.7 guys. GOOD gaksets, strong as you can get head bolts, and if you can stud the mains, do it. Do not underestimate the forces a boosted engine can do.

Consider my 301 Turbo, 290 rwhp (rated 210hp, calculated 290 rear wheel hp, based on 14.21@97.3 mph 1/4mile, 4030lbs, and 3.08 gears) and if you ever saw a 301 heads, crank, cam, and turbo, you would be amazed at what it did. That was with a 301 CID engine, 7.5 psi boost (low for a 301, stock is 10 psi), a beefy turbo block, HD pistons with the offset turbo dish, and a static compression of 7.5:1. So starting off with 9.5:1, and no timing mangement for pinging under boost, is the starting of a recipe for distaster.