853's vs 317's
 

My spare LS1 that needs a valve has a set of 853's on it right now, but the broke LS1 in the car has a set of 317's that came off of the spare L92 I got with the car, IIRC. I was told the exhaust side of the 317's have been cleaned up by a reputable machine shop in Wilmington NC. The broke LS1 with a MS3 and 317's made 414 to the wheels before it spun some bearings.

My question is can I run the 317's on my new motor with no PTVC issues while running the MS4 that's in the new block already? I don't think they have been milled or anything. I understand that I will have to check PTVC, but are 317's basically the same? Also, will I have to run bigger (6.0) head gaskets?

I rather just swap the springs from the heads with the bad valve and run the 317's on my LS1, if this is possibe. Also, will the springs be interchangable from 853's to 317's?

Let me know what you think.

Your compression is going to be lower. I'd run the bigger head gaskets.

Which head would net more gains?

stock for stock the 317 flow more but have larger chamber so if not milled, the scr will be lower with stock unmilled 317
317=71cc
853=66cc

So would it be worth milling them and throwing them on the full bolt on, MS4 LS1?

If you don't plan on adding a turbo or super charger, either get them milled or trade them for some 243 heads from someone wanting to do the opposite as you.

It's $100 bucks for me to get them milled to 68cc's at a reputable machine shop here in Charleston. Would you guys go any lower than that? I am still fairly new to the technical side of LS1's... That would be a different story if it were an LT1.

Also, can anyone confirm what head gaskets I would need to sue with the 317's?

Thanks guys!!

Any other opinions?