compression or flow?

Yes, you are incorrect.


Where in the mention of a cam in this thread?

Horse before the cart?


Yep! In that sea of calculators….. it’s there!

Also @mopfried

Bad move mostly if not every time. It’s been proven otherwise. Search member IQ52 for his results .





The available octane and timing curve are more important to this than anything else.




A zero deck .030 over flat top and a 70cc head and a .038 X 4.xxxx head gasket will deliver a very friendly local gas pump 91 octane while keeping the ability for a good timing curve.

The ratio will fall in around 9.7-1 - 10-1 depending on head gasket and head cc amount.

This I have done in the past, it’s not a problem.


Purchasing pistons to match a W2 head, to me, seems like your saying get domed pistons. I call this a bad move since the extra dome material is pushing the ratio, perhaps, maybe, over a 91 octane limit. 93 should still be in the ball park. It was for me.

Another possible draw back to a dome slug is how high the dome is and the work around them dependent on dome height and shape. The possibility of and IMO, for sure in my wheel house is to knock off the sharp edges and soften the slug to help prevent detonation.

Cylinder head flow (and with a capable intake!) makes more power than increasing the compression. While it’s really needed more and more for a large cam and the larger the cam is the more compression is needed to off set the overlap and loss of dynamic compression at low rpm.

Smallest cam I ran at 10-1 with iron heads was a MP circle track cam, 288/.497(?) - 108, also ran the Hyd 292/.508-110. I was in NY at the time and 93 octane was more than enough.
I have a strip dominator W2 intake. TTi W2 1-5/8x1-7/8 step headers. I have an old Crane SSH 320 cam that worked pretty well on an old 340 that closed @ 46 deg ABDC. 496" intake and 504" exhaust. I believe it was some where aroud 243 deg duration. I would probably look fr somethuing like that with maybe more lift.