My2kz28

iTrader: (1)

Mods are in sig, But I have a 93 z28 with a rebuit lt1 (355). I have SRP forged dished slugs making 9:1 compression, forged Eagle H-Beams, STOCK lt1 crank with ARP bolts on the main caps as well as in the heads. Its a supercharged application, and on 11 psi I made 450 rwhp at 6000 ft (596 rwhp corrected)

How much power will my bottom end handle? Corrected #'s aren't as important to me, but in general, how much power is a 2 bolt lt1 capable of holding?

cruzin94

iTrader: (2)

probally more then that stock crank and if ur worried get splayed to a 4 bolt main and i hear there alot stronger then a factory 4 bolt like a vette engine

396D1SS

iTrader: (21)

I have seen alot more power run a long time without failure. As long as you dont rev to the moon you will be fine IMO

daniel6718

iTrader: (36)

well rwhp is hard to judge you could have from 10%-40% drivetrain loss

engineermike

turbo355 over on turbomustangs.com has made over 700 rwhp and run 9's at 140+ mph with a stock 2-bolt bottom-end SBC and Badger pistons. Probably the exception not the rule though. . .

borninatransam

iTrader: (4)

its all about the amount of boost, the tune, and how hard you drive the thing. if you take it out and beat on it everyday of course the thing probably isnt going to hold up long, but if youre talking about it being a weekend warrior i wouldnt worry about it. like engineermike said 700 has been done and i wouldnt be worried to run 500-550 on a consistent basis.

ZONES89RS

iTrader: (25)

Id say you could go with 500 RWHP and get away with it with no problems, 550 even.

97ssmokem

I had 605 RWHP on a 2 bolt and had no problems.

engineermike

I bet the caps were walking around a bit. turbo355's didn't blow up, but the caps were fretted quite a bit underneath. At that point, the crank and mains probably won't last long.

My2kz28

iTrader: (1)

So if i ran 500 rwhp at 6000 feet above sea level, My bottom end would last?

dwhiteZ28

iTrader: (5)

ttt...Im going to be buying my f1a PROCHARGER today and I want to make sure that 500 rwhp will hold together. It will be tuned conservatively.

SS1156

iTrader: (4)

With a F1a I would definately go splayed caps. This way you can turn up the boost in the future. Hell I'm going to be splaying my caps with a 200 shot.

dhdenney

iTrader: (53)

You could probably make 800 horse on 2 bolt mains if you could do it in the lower RPM ranges. I'd say it's RPM that walks the caps, not the power. Any engineers or builders confirm? Also "shock" like sudden nitrous hits too. Just my opinion.

engineermike

I imagine that the massive cylinder pressures required to make 800 rwhp at, say, 5000 rpm (1100+ ft-lb at peak torque) would cause some cap walk.

CNC Stew

What he said. ^

My2kz28

iTrader: (1)

So if I splay the block for the 4 bolt mains, how much more rwhp will that support with ARP bolts, and stock lt1 crankshaft? What would it cost me to splay the block?

dhdenney

iTrader: (53)

Well hypothetically speaking of course with a N/A engine. I guess we'd be talking like 25-30 psi of boost. Yeah, I reckon that would walk the caps.

ZONES89RS

iTrader: (25)

Ok, there is a guy in car craft this month and has a 89 GTA with a old *** bone stock 76 350 with twins pushing over 700 RWHP, so that should say somthing.

Mike@ZMS

iTrader: (10)

I wouldnt expect a stock 2 bolt LT1 with any amount of miles on it to stay reliable much past 500. Its all about how it goes about making that much power though. If you rev the **** out of it, it will break sooner than if you were to boost it with a proper FI setup.

engineermike

See post #5.