I guess at this point the question is, is it a different head, or a CNC ported version of the std head?

Edit:
I just checked the link.
Looks like it's a CNC ported version of the std head.

How soon will we know how they compare to Trickflows?

I'll take a w.a.g. and say you can use the published data for the MCH CNC-ported Stealth or Edelbrock Performer RPM for comparison.

The MCH CNC rpm/stealth porting program is more like 251cc, so if these are 11cc less.... One might "assume" they would flow a little less.

That's why I said w.a.g. instead of s.w.a.g.

Would the CNC version make sense on a low deck, Street, 512 build?

I would think these heads would work nicely for stroker street motor.

I'm going to (eventually) build a 451 low deck since I picked up a 440 crank that has already been machined for the application. Tempted to run the trick flow heads because of the combustion chamber but honestly, I would probably be happy (aka, make plenty of power) with the unported Promaxx heads too.

anyways...

got an email back from Promaxx. I asked about their hydraulic spring application...


Lift intake exhaust
.200 157 108
.300 224 152
.400 275 184
.500 305 208
.600 318 227
.700 323 239
.800 327 247

The specs of the head stays the same, so the combustion chamber would stay at 84cc's. The manufacturer of the springs for this application is Pioneer.

If they flowed that on my bench they would be better than the TF heads.

I for one don't think that would be the case........ But "ya never know".

i just found these pics of the promaxx CNC ported heads. the price for these heads bare is pretty high, jegs has them complete for 1700 i think. I would wonder if all the CNC heads have the chamber done like on this listing.
at 90cc in the chamber that might be a good option for someone trying to keep compression down some.

there are small block heads listed too.


promaxx BB


promaxx SB

The assembled heads are more money than the TF 240's...... And they're Chinese castings.

IMO, TF pretty much has that market covered as long as they keep the prices similar to what they are now.