x3 and 317 heads
06-01-2008, 08:37 PM
#1
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x3 and 317 heads so i have a G5x3 on 110 in my car now. it has stock heads. im going to buy some 317 heads. my question is how much can i deck the heads to get my compression back? i will be using the stock 5.7 mls GM replacement head gaskets again, i already have ARP heads studs also. also, will i have to get shorter pushrods? im at the stock 7.4 length right now.
07-06-2008, 03:48 PM
#4
Not retarded... drunk! What i was saying is by milling your 72cc 317 heads down by 10cc you will disrupt the intake flow by shrouding the valves against the piston/cylinder wall. I have heard milling more than .030 will do this. It will also create valvetrain geometry issues (i.e. pushrods not meeting rockers correctly) and intake alignment issues (since the intake ports will be futher apart the more you mill them) I am not entirely sure how much but i would say .020 on the safe side. You'd be better off having the chambers welded or just going with a set of LS6 heads. Ideally ported 5.3s with larger valves.
07-06-2008, 04:56 PM
#5
so i have a G5x3 on 110 in my car now. it has stock heads. im going to buy some 317 heads. my question is how much can i deck the heads to get my compression back? i will be using the stock 5.7 mls GM replacement head gaskets again, i already have ARP heads studs also. also, will i have to get shorter pushrods? im at the stock 7.4 length right now.