I am assembling my LQ4 with a MS4 and 799 heads (Same as 243's) I know clearances with P to V are very close, and measuring is ultimately the only way to know (I will be using clay method) I would like to know if anyone else has run a similar setup without problems?

When I dropped my heads off to Napa I told them not to mill over .003" to .005" at the absolute most, if they needed to be cleaned. And of coarse when i pick them up I asked how much they milled and he said " I only had to mill them .005"-.006" !!!!, I proceeded to tell them the dilemma they just put me in, and now i'm here. I picked up an Autozone Fel pro stock replacement head gasket which should be close to .048-.050 crushed..

Should I call Napa and make them flycut for free for over milling my heads? Or just assemble, check and run it?

 

Honestly, it would have been tight at .003-.005" of milling, and that extra .002" or so isn't going to be the end of the world. The last thing I'd want is NAPA flycutting my pistons

You might consider degreeing the cam in to ensure the valve events are where we intended them to be when designing that cam...that'll also ensure the best piston to valve clearance possible typically. Let us know if we can help!

 

Alright I agree with not letting Napa fly-cut. As far as degreeing I called your shop before my install and was instructed to install it at 0 degree (Straight up). I basically followed the LS1 How to install cam guide to the T. Do you mean I would need a Cam alignment tool and adjustable cam gear? I feel fairly confident with my install and just checking with clay. But if you strongly think I should do some more preventative measures then i will. Thank you for your time and advice Matt, you guys have been exceptional.

 

i think you should be fine remember that a lq4 has a .050 dish that gives you more ptv clearance then a ls1 or lq9 the only question i have is why run the fel fro gaskets when you can get gm ls2 gaskets for the same money or less

 

You're likely fine, and if you check with clay you'll know if you need to advance or retard it a bit, but it's always nice to do on such tight combos like yours!

 

Thanks guys, I am just going to check with clay and go with it... I ran the Fel pro because of availability... and I have been happy with all my other Fel pro products so far. Im crossing my fingers and putting it back together tonight. Then to the dyno next week.

 

Hey bro, just wondering if you ever assebled block and if you had any PTV problems, am doing about the same build, but going to be carbed.