Budget LQ4 build compression?
Thread Starter
Staging Lane
Joined: Oct 2009
Posts: 97
Likes: 0
From: Frederick, Maryland
Budget LQ4 build compression? I just got my hands on a LQ4 that needs to be rebuild, it has the 317 heads on it now and since I need to do the pistons anyway I think I can get away using domed pistons with the 72cc 317 heads to get up to a respectable compression.
All the ls2 pistons I can find seem to be for a 6.125" rod. Whats up with that? isn't a stock LS2 rod 6.089? are aftermarket rods required? would it be more cost effective to do a OEM 4.030" flat top LQ9/LS2 with LS6 241/799 heads?
I want to build for a decent streetable N/A motor and add N2O later.
All the ls2 pistons I can find seem to be for a 6.125" rod. Whats up with that? isn't a stock LS2 rod 6.089? are aftermarket rods required? would it be more cost effective to do a OEM 4.030" flat top LQ9/LS2 with LS6 241/799 heads?
I want to build for a decent streetable N/A motor and add N2O later.
Thread Starter
Staging Lane
Joined: Oct 2009
Posts: 97
Likes: 0
From: Frederick, Maryland
I would like to get into the 11-12:1 range with ethe compression. My thing is that since I require a rebuild anyway (water in some cylinders) I can buy whatever pistons I need to get the compression I want, even with the 72cc 317 heads. to my knowledge the only diffrence in the 317's VS. the 243's is combustion chamber size, flow is the same.
I already have a pair of 317's that came W/ the 6.0 so if I can get some 10-15cc domed pistons that will work with the stock LS1 rods I won't need to buy heads right away.
IF there is no such thing as a 10-15cc domed piston that will work with the stock crank & rod, I guess I will have to use a flat top piston and 243/799 heads. there are dozens of stroker domed 4.030 pistons out there (6.125 rods & 4" stroke)
I already have a pair of 317's that came W/ the 6.0 so if I can get some 10-15cc domed pistons that will work with the stock LS1 rods I won't need to buy heads right away.
IF there is no such thing as a 10-15cc domed piston that will work with the stock crank & rod, I guess I will have to use a flat top piston and 243/799 heads. there are dozens of stroker domed 4.030 pistons out there (6.125 rods & 4" stroke)
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
What you do is get flat top pistons with reliefs and then mill the 317s, thus still allowing a respectable cam to be shoved in there.
Wiseco offers pistons with -3.2 reliefs but require block shaving to run stock 6.098 rods.
6.0 blocks are 9.230 deck height so to achieve 0 deck height you would need a .017shave.
http://www.wiseco.com/Catalogs/Automotive/Chevrolet.pdf
Wiseco offers pistons with -3.2 reliefs but require block shaving to run stock 6.098 rods.
6.0 blocks are 9.230 deck height so to achieve 0 deck height you would need a .017shave.
http://www.wiseco.com/Catalogs/Automotive/Chevrolet.pdf
Last edited by PREDATOR-Z; Oct 25, 2009 at 11:16 AM.
