Mike Cordero

iTrader: (122)

I have a LQ iron block with the standard crankshaft. I have the option of use LQ4 dished pistons or the LQ9 flat ones. I would like to use the LS3 heads (821, 823, etc.) for a street, show turbo 1954 chevy truck. Due to the big valves size, which pistons would I choose? I would like to use a mild but slopy cam that doesn't make another problem with the piston valves issue. Which pistons would be better from the ones that I have?

Mike Cordero

iTrader: (122)

Someone can help me here?

Mike Cordero

iTrader: (122)

Needs advice.

omc8

iTrader: (7)

Well if its a turbo go with LQ4 pistons. Im a big fan of LS3 heads, but don't really think you need it in this application. The 317s if ported will pull stronger low and mid range ,than the LS3 heads. The chamber volume is pretty much the same at about 71cc. Just depends on your goal and budget.

Crf450r420

iTrader: (1)

plus you need more spring to keep the keep the larger intake valve closed. Can be a big issue at high boost levels. Unless you plan to high boost keep the CR up so it's not a dog before you spool.

Atomic

iTrader: (37)

Need a lot more info...especially your power goal. From there we can recommend a turbo, head, and piston which will determine your compression ratio. There is about a half point difference from the dished LQ4 pistons and flat LQ9s. Since you mentioned these I am assuming you want something reasonable like 600hp or so. In that case either head will be fine, although 317s can be had much cheaper. I would do the LQ4 pistons in that case. Youll never know the difference under boost but the engine will be more knock resistant.