Generation IV Internal Engine - 1000hp from a LQ4 block?




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Trav4011
06-10-2012, 10:10 AM
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
06-11-2012, 01:15 AM
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
06-11-2012, 08:57 AM
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.

http://ls1tech.com/forums/parts-classifieds/1553397-race-prepped-6-0-iron-lq9-big-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.


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