318 with 340x heads sluggish

RustyRatRod said
It takes about a .070" cut to equal one compression ratio. You'll have to mill over .100" to get compression on the high side of the 8s. Then you'll have to have the intake milled to match. That's a LOT of cuts for the machine shop, because they cannot do it all in one pass. It's not gonna be cheap, plus, you'll have an intake that you can ONLY use with THOSE heads. Get a clue. That's not the right way to do things. DO it right, or take up solitaire.

You cut both sides of the head, block side and intake side. You can use any intake as long as no one has Dorked with it. Since uncut 318 heads are 68 cc's and you are running 65 cc 360 heads, where is the big compression loss? Yes, we are talking 4 passes on the machine. But I always go at least 2 if they have never been cut anyway. You also go from 170 cfm to 210 cfm intake flow, unported. If you want more compression, get pistons.