Sup guys am doing a semi built on 1172 and i was wondering what is the max boost that the block will hold. The car specs is as follows. I will be running the ostrich with the setup
I want to run around 35lbls you guys think the block will hold. Also this is a jdm cyclone motor.
scm6052 turbo
dnp manifold
1000cc injectors
bc springs and retainers
hks cams 272/272
supra fuel pump
Bosch 044 external fuel pump
Arp head studs, cometic headgasket

The 4G63 block will handle more boost than you will ever make with that snail.

The block is the strongest part.

(Edited it because I typed the wrong block number /ubbthreads/images/graemlins/banghead.gif)

I'm guessing you mean on a stock short block. With a good tune a stock short block will live quite well up to around 500whp. Much above that and you're pushing your luck. There isn't really a certain PSI that is the magic limit.

Well a certain big boost guy made the normal arp's stretch and melted a head at 41psi but now has went to L19's and full everclear so the monster should rock now or pass out trying.. /ubbthreads/images/graemlins/grin.gif

yea am talking about the shortblock am just trying to find out if thestock block will be good for a high amount of boost before crapping out.

All depends on the tune, I know a few people in the 10's on a stock block. PSI is just a magic number, all about airflow also.

the stock shortblock: Block, pistons, rods, hardware are all capable of taking in excess of 500hp and living for a long time. Honestly, there are a few people pushing low 10's and more than 140mph in cars with original shortblock. No one has honestly pushed the stock block to a consistent failure point to where we really know what the limit is. It could be 650hp on a perfect tune for all we know, but seems anyone willing to spend the coin to make that kind of power has a build engine in the plan from the start anyway.

Another point: it's really not about PSI or Airflow...in reality it's going to come down to RPM and rod bolts. To make big horsepower, you invariably have to rev the motor higher due to larger turbocharger spool, bigger cams, intake manifold. All the parts that you would use to make a 600hp engine cause the powerband to be moved up in engine speed. My gut tells me that turning 9000rpm on stock rod bolts is going to fail fast, maybe even before the piston or rod fail due to pressure force.

If you could find a way to make 600whp with a 2.0 engine and have peak power under 6500rpm, my bet is the engine would last without trouble. But any 2.0L turbo/cam/intake combo that can churn out 600 at the wheels is going to have a 6000-9000 powerband.


I'm running a stock block in my GVR4, and I currently don't feel I was pushing it that hard yet. Next year Im going to upgrade the headgasket and possibly the rod bolts while the engine is on the stand. I'm considering nailing it with a bigger nitrous hit, maybe upwards of 150shot on top of a 30psi 50trim turbo setup. (the car only does 126 on the turbo alone..maybe 425whp?). I shift it well before 8000 and run the 264 intake cam. I'm pretty confident the shortblock will stay together with about 550-600whp and should hopefully do 140mph on bigger shot.

From looking at your mod list in the op, you have nothing to worry about. you should be able to run that 60trim as hard as you can without the shortblock failing. (unless you detonate it, then all bets are off at even 350whp)