Trav4011

Trying to decide on which route to take.. I don't know much about the iron blocks, so I figured I'd ask. Will the LQ4 block support around 1000whp through a TH400? I'll be running a pair of billet 67's (T4 based), and LS3 heads. Stock bore.. What would you guys recommend stroke-wise? I'd like to keep the compression height and rod/stroke reasonable, as I don't want to chew up pistons/rings. Also, should I machine for larger head bolts, or will stock diameter in a L19 alloy work? So, just a few questions before I get started.. Thanks for the help.

Travis

gnx7

iTrader: (28)

Ditch the LS3 heads and spend the money on some quality thick deck heads.

I did have a buddy make 950rwhp+ on LS3 heads on a 378ci LS3 forged motor.... (with turbo) and no head sealing issues. Main issue was rear main seal leakage which was solved with a GZ Motorsports vacuum pump. An LQ9 iron block will take 1000rwhp. Beyond that HP level and the limit will be the 4 bolt heads to keep the head gaskets sealed. Most run LS9 gaskets with ARP head studs. Make sure you have the tune spot on.

helicoil

iTrader: (104)

I have done a couple of these, both of which are still going strong. The LQ9 is plenty stout to handle those needs.

I usually have them prepped the way this one is.

https://ls1tech.com/forums/parts-cla...boost-new.html

The 1/2" head studs help a bunch, the main dowels are very important. Keeping the bore the smallest you can will help in cylinder strength. A standard stroke would be a very reliable package with those twins, although a 4" crank will work too. Lots of piston strength in the stock stroke version and they are available off the shelf without custom ordering.