'68-'73 340/360 heads part 1

[@jonathoncouchey7151]

The later 596 heads are very similar intake port wise to the j head. I ported the heavy out of some 1.88 valves 596 heads. I actually preferred them the the #308 intake wise. But the exhaust on those #308 heads are extremely nice. I have a the set of 308 heads waiting for when I want to cut them to 2.02 size and port them out on my homemade flowbench. No accurate cfm. Just able to make sure it flows the same every time with a known piece I have flowed. And using a pito tube to measure airspeed for port stability.

[@christopher5585]

Im not much of a #'s matching guy but I have owned and ported 894, 915J (360) and 587 heads. The J and 587 heads are basically the same and measure around 72 cc. I've had J heads machined for 2.020 Intake (Ferrea) valves without the VJ and it then measured 65 cc. Those Ferrea valves are also .020 inch longer than stock. The pushrod Area Pinch can be opened up to just under 1 inch. .950 wide is safe and sll that is needed is to blend it in with a Felpro Gaskacinch Gasket. The Valve Guide Boss can also be reshaped as with the Roof Hump. All requires hoys of dedicated, steady hand work. Is it worth it ? Shady Dell, which is now non existent did much of the testing on every SBM head from stock to current offerings. With Maximum work, an X,J head can reach up to 269 CFM. Darn good for a Street Head, if you're willing to invest the time and money.

[@samuelgoodman2825]

Got a set of J heads on a 65 Dart 273 .30 over.Nice combo.

[@lenmaryan7943]

I wish 270cfm is achievable, with that little work. Maybe at 28” A W2 doesn’t flow that, without some work.

[@1WILDsMoPARtech]

In no way did I intend to insinuate that with just removing the guide kink in the roof that an X head would flow 271cfm. These heads have quite a bit more work than that into them to flow 271cfm. I'm just not showing you that work in this video.

[@smilsmff]

I think the 6 pack heads had same I.D. #'s as J heads did. not sure but that would have been a good way to sneak in NHRA class and win some money back then in 1970s.Also hey which Valve size on the intake did you use to achieve 271 cfm on the "X" Heads that you said that you ported?

[@1WILDsMoPARtech]

Elgin 11/32 2.02 w/ undercut stem. Turn becomes low and flat topped n rolls right down to the lower angle. The valve job is low pro 3 angle with radius serdi cut around the top angle in chamber. I'm not sure what's impressive anymore, it's all become kind of irrelevant. I'm at crossroad in life and what was very important seemingly isn't atm.