XR274HR-10 in 318

OK if you are going to port do it and get head flows for input into your cam choice
also get true compression with aftermarket head gasket
Someone got a Howard for $150 with a changed exhaust lobe- must have been a HFT I forget but not much of an extra charge
I'm not saying 26- or 264 is the right number for you
I was just saying you could get the larger cam performance with the small cams driveablilty/ torque