Patrick4588

I have a 227/239 .614/.624 113+3 cam and basically 2 bottom ends to pick from. Alum 5.3 lm4 and iron 6.0. Going to use 243 heads. Should i be worried about valve to piston clearance with either? Id like to mill the 243s to bump compression up as well but brings even more concern about piston/valve clearance. What whp difference am i looking at between the two?

Patrick4588

Car its going in weighs ~2300lbs and paired with a fti stage 3 th400

Darth_V8r

iTrader: (4)

The 6.0 is a better match for the cam imo. Whichever bottom end you pick you will need to clay the pistons for ptv.

Patrick4588

and if hit just fly cut them?

speedtigger

iTrader: (16)

With that camshaft, you should be able to mill the heads up to .020" and still have acceptable valve clearance.

Darth_V8r

iTrader: (4)

I agree, it should be fine. And yes, you use the clay to measure PTV. if it is too close, then make plans to flycut.

rpturbo

iTrader: (47)

I have 799's on my LQ4, and had tons of room, but always clay it up to be sure, and remember the piston chases the exhaust valve.