im normaly over on ls1tech, but since i bought a 6.0 (lq9 not lq4) for my 73 firebird i thought id ask you guys im putting an ls6 intake, longtubes, 4l60e on it and was wondering whats the max lift you can safely go to with the lq9 engine? right now i plan on running the stock rockers, valves, mild porting, 918's. not to be a drag car but a strong street/ daily driver. any cam/torque conv suggestions welcome thanx for any info joel

 

With those 918 springs I wouldn't go over .580 even though they are rated to .600. As far as piston to valve clearance limitations, you can easily go .610-.620 on unmilled heads with stock valves and a good set of dual springs depending on duration of the lobe.

 

I'm more daring I guess, I wouldn't be scared to go .600 with my 918's as long as the rpms were kept relativly low ~6500 or so. But Big Kid is probably right. Just to be safe, stay around .580 or so.

 

thanx guys and i was worried about a 551 lift. i just wanted to make sure the pistons and valves dont try to cross pollinate. joel