"ProMax" cylinder head review (2024)

I have been working on a set of "ProMax" cylinder heads for the past number of weeks. This is the first set of this brand I have had to work on so I thought I would make public some of my findings.

I don't know where these are really produced and I'm not going to guess. At first look they seem just like any other aftermarket head, they have seats under both valves, they have some sort of black paint or something all over other than where the machining has been done.

The runners are the WORST I have seen, casting shift is major, excess slag is everywhere, the machining in the bowl area is off from one hole to the other.

Once I started roughing in the ports some of the slag would flake off like the paint was holding it in place. There are deep voids / pits in places, extra material hanging in places it shouldn't be, and much more poorly placed material than other brand heads.

I have spent a large number of hours on this set reshaping and removing material to get these where they should be.

This set isn't done yet but when they are the port work and coatings will be on par with any other brand of head they just require many more hours of unexpected work on my part.

I'll post a few before pics now, and after pics when finished.

I can't speak of quality or if the inside cooling passages are different at this time, I doubt I will purchase a head to cut up just to see, I have and will continue to recommend P400 heads as the BEST, real GEP heads would be second.. I never recommend any aftermarket head..

I have done many many 6.x heads over the years so this is my honest review of the "ProMax" heads...

snarl95 said:

This is a good example of spend less and spend more.

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Well, not really for the customer in this case, my price is firm for my services, the added work is just on my end, the product will be as it should be when it leaves me no matter what it takes on my part..

At what point do you just cut these heads up and send them the P400 heads? I have a hard time imagining this much work put into low quality casting heads.

The casting looks flawed even into the valve guide?! Or is that paint over-spray?

So have you found the clean end to pick em up by yet?

quadstar87 said:

Banghart Diesel & Performance put down 355hp/659tq through a set of ProMaxx heads recently and a bunch of other parts from us. No major work was done to these other than a basic gasket match job. We'll be pushing them to 400 here in the coming weeks.

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Do you have any pics of how their heads were/are? The pics from above are pretty rough. Just wondering if the set that was sent to TSP was total junk, or the set that went to BDP was and exceptional set, or what is normal to expect from them.

Also interested in the rest of the build or is it a "secret sauce" scenario. Those are some descent numbers.

Will L. said:

Do you have any pics of how their heads were/are? The pics from above are pretty rough. Just wondering if the set that was sent to TSP was total junk, or the set that went to BDP was and exceptional set, or what is normal to expect from them.

Also interested in the rest of the build or is it a "secret sauce" scenario. Those are some descent numbers.

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No Secrets to the combo, it's all been posted on our FB pages. That run did have methanol injection and the turbo combination was still holding it back some on the turbine side. They are going to be doing more runs with a new injection pump from us (the same one going with this set of ported heads that TSP did here on this thread also). Will be interesting to see how they compare in the end.

Will L. said:

Do you have any pics of how their heads were/are? The pics from above are pretty rough. Just wondering if the set that was sent to TSP was total junk, or the set that went to BDP was and exceptional set, or what is normal to expect from them.

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We didn't provide the heads, so no, we didn't see them.

quadstar87 said:

No Secrets to the combo, it's all been posted on our FB pages. That run did have methanol injection and the turbo combination was still holding it back some on the turbine side. They are going to be doing more runs with a new injection pump from us (the same one going with this set of ported heads that TSP did here on this thread also). Will be interesting to see how they compare in the end.

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You should post the current set up in here. Because Im sure Will L. and many others on here don't have a FB page.

Twisted Steel Performance said:

Are you going to run the heads I did as well as another IP John ?

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I hope the customer does! I'm sure the head work done here will only help. He has indicated he definitely wants to but the current state of things has slowed down his build somewhat. We'll be involved as much as we can if he does make it to that stage.

Banghart's truck is getting a different pump and turbo and going back on the rollers since they can run it in-house as much as they want. (which is nice - the truck, dyno, and operator are all staying consistent between runs) That dyno sheet above was the max fuel command on a stock DS pump, plus meth. The rough estimate is 40-50 cc more fuel and a better turbo that's not choking on the turbine side.

quadstar87 said:

Shocking. You don't agree with it. We are all shocked

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You called him out on Facebook yourself...

"Post what size nozzles are in the meth system! Love this sh*t but don't mislead innocent people into thinking you went over 300hp on a stock pump without meth "

Rockabillyrat said:

You called him out on Facebook yourself...

"Post what size nozzles are in the meth system! Love this sh*t but don't mislead innocent people into thinking you went over 300hp on a stock pump without meth "

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So you are quoting a reply we made to make a post entirely transparent to the public that the run was done with meth? What's your point again, exactly? Should we have hid that and let people believe it was done on fuel only?

This post is about cylinder head flow and it doesn't matter what fuel you use to make power to move air through them for this discussion. Please quit repeatedly wasting my time with your games.