[abbadon3718]

Originally Posted by oldman

A street driven car undergo FAR more stress that a tailored race 1/4 mile. GM for 650 Hp went to a titanium intake valve vs the hollow steel LT1 valve. Just one example. GM has to provide a warranty, ask your "tuner" if he is willing to do that. It is a near joke to pretend a 1000+ HP on production cast components, NA engine can live in any sort of street driving scenario, much less anything in the drive-train. I've already pointed out 3 cars at the power level we are talking about, with build engines / components, 2 out of 3 of them failed in a few days of testing. THAT IS REALITY. For me "safe" in a DD that can go 100,000 miles and IMO it can't be done at all no matter the budget at 800 WHP. I think 730 whp maybe doable, just maybe, with top shelf components, hopefully, just maybe... but probably not. Do I know what will fail? I got a pretty good idea and it consist of just about EVERYTHIHNG in the drivetrain from lifter to valve to the undercut crank, to the input shaft of the M6 trans to the donuts on the driveshaft to the axles to the welded ring gear. Your on crack if you even pretend a 9 second car is a DD without a fat wallet and a mechanic on call.

Fair points, all of them. I thought we were just talking about bottom end though so I was just focused on crank/rods/pistons and at what points they would likely fail. People on here seem to focus on pistons/rings, what would you consider safe for rods and crank with drop in pistons Oldman?

[oldman]

I also like a solid intake valve EV-8 spec minimum. The exhaust valve is solid stock so IMO it is OK to 700 or so WHP, above that I'd go XH-428. If you don't understand what I'm writing about you have no business building a 1000 HP engine.

I'd also like to see sodium filled Inconel, I don't really like hollow valves but it is hard to deny the cooling benefits of sodium. I like a solid valve with undercut heads that is why I went with Manley Pro-Flow.

This is just the VALVE!!!! So many other components are iffy on a DD defined above.

[oldman]

Originally Posted by abbadon3718

Fair points, all of them. I thought we were just talking about bottom end though so I was just focused on crank/rods/pistons and at what points they would likely fail. People on here seem to focus on pistons/rings, what would you consider safe for rods and crank with drop in pistons Oldman?

I went with 11.5 CR drop-ins. I knew at least for this engine and also my M6, I would be running minimum boost. IMO 750 WHP or more I'd go with REAL rods and pistons and minimally a LT4 crank (rolled fillet). I'd run a modern I beam rod:
http://blog.wiseco.com/wisecos-new-2...onnecting-rods
I'd run a piston with a boost friendly ring land and MUCH heavier than the stock piston (cut valve notch for sure). 10.5 CR. The stock weight rods / pistons are severly compromised in engine builds above 750 WHP (825 engine). Same on the production undercut crank, actually a crap way to "strengthen" the crank. The LT4 is a rolled fillet AFAIK.

BY reading this it would seem both are rolled, from memory my LT1 crank was undercut (matters which way the rod faces as only one side is beveled to clear the fillet), but I'm OLD!!!

"We spoke with Mike Garza, design system engineer for the block, crank, cylinder head, valvetrain, and lubrication system, who told us that a forged LT1 crankshaft would fail during extreme dyno tests when subjected to LT4 levels of power, so they engineered a unique crankshaft. Compared to the LT1, it has increased rolling loads (the amount of force applied to the crank fillets). Steel wheels are rolled over the fillet at an angle to extend the fatigue life. Because the cranks were failing at the same spot at the rear of the block, the lightening hole at the last rod journal was eliminated and tungsten slugs were added to the No. 8 counterweight to compensate."

http://www.superchevy.com/features/1...te_z06s_lt4_v8