Swapping out iron J 202 heads for aluminum

Mopar204 said

Looking to swap out my slightly ported J 202 heads with the promaxx 185 shockers cnc
Just asking the experts here on what they thought about my setup and these heads going together. I’ll list my specs and my cams specs for you guys
Also willing to swap out my cam if needed

408 scat stoker kit with 20cc dished forged pistons
-mopar m1 single plane intake
-lunati hydraulic roller cam and lifters(Advertised Duration 270/278, Lift .515/.530)
-j 202 heads ported (64 cc)
-holley 750 carb
-9.7:1 CR

here is the link to the promaxx heads I’m looking at getting.
Shocker 185 Mopar CNC (Sold in Pairs) - PROMAXX Performance Products
Ive heard good things about them.

Click to expand...

I like mine. There pretty good. The racked shaft stands should be addressed. There machined a bit shallow, the rocker shaft should sit in them more.

As said, a lot depends on what your heads flow now, at least up to the lift of the valve. If both heads flow the same or very similar up to your valve lift, there will be no gain really.

Looking at your combo, the cam is very small, but if it performs in the rpm range of your use, then leave it. A nice upgrade would be 1.6 rockers for added lift to take advantage of the cylinder heads increased air flow.

He single plane is hurting performance. You will pick up a good bit of very noticeable torque by switching to a RPM intake. That M1 single plane is really designed for use in the 3,000 - 7,000 rpm range. This is a cam duration approximately in the 250*@.050 range as a minimum.

You did not list the cars weight, gear ratio, tire size and transmission being used. If it is an automatic, going to a larger cam size will necessitate a higher stall converter.