Promaxx 225 heads

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Monza355
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Re: Promaxx 225 heads

Post by Monza355 »

harry k wrote: Thu Jan 14, 2021 12:56 am They are comparable to AFR 220cc heads, They will really SHOCK you if they don't meet your expectations!
Are you using these heads on your engine ? If so.. what combination is that ?
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Re: Promaxx 225 heads

Post by steve cowan »

Monza355 wrote: Wed Jan 13, 2021 8:34 am
mag2555 wrote: Wed Jan 13, 2021 7:31 am First off if your motor is only 355 cid, or even 383 cid you will need to be buzzing it well .above 8K rpm to make good usage of 225 CC SBC heads
It’s a 434 cubic inch engine i have. Maybe i should have mentioned that.. I’m looking for good heads, that can use a standard rocker arm. I’we been eyeballing the 225cc Brodix Dragonslayers as well. I just haven’t heard many reviews on these heads.
I would private message Eric Weingartner or Google Eric Weingartner Racing,should be able to find him.
Eric does alot of brodix heads he is well respected and competed in EMC and is a racer as well.
Starting point for me would be for a 4.155" bore 434ci
2.10"- 2.15" intake valve.
230cc - 240cc runner
Avg CSA 2.60"
This is a starting point to peak approx 6500rpm
Good luck with your build :D
steve c
"Pretty don't make power"
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Re: Promaxx 225 heads

Post by rustbucket79 »

I like the AFR 245’s, and I should since they are on my drag car. :mrgreen: Nothing special 12.5:1 406 runs 10.0x at 134 in my 32xx# Camaro.

In my opinion a 434 displacement small block is race territory and the heads installed should be sized accordingly. Brodix/Profiler/AFR/etc in the larger sizes is where I would be looking. I’m sure there are people here that could accommodate as well. A budget head on a 434 is going to peak way early and disappoint you, even with the proper solid roller cam.
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Re: Promaxx 225 heads

Post by PRH »

A budget head on a 434 is going to peak way early and disappoint you, even with the proper solid roller cam.
Kinda depends on what your expectations are, no?

Anyone flow a PM225 and something like an AFR220 on the same bench/same bore?
Somewhat handy with a die grinder.
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Re: Promaxx 225 heads

Post by rustbucket79 »

PRH wrote: Sat Jan 16, 2021 10:36 am
A budget head on a 434 is going to peak way early and disappoint you, even with the proper solid roller cam.
Kinda depends on what your expectations are, no?

Anyone flow a PM225 and something like an AFR220 on the same bench/same bore?
I don’t consider a 434 a budget engine. I don’t like the 434 in a standard block (std deck and cam height) because everything is fighting for real estate, and the pistons are hockey pucks and rod shoulder to cam lobe clearance is a real issue with production camshafts.

Does one go through the effort to build or buy a 434 just to bolt a set of 450 hp heads on it?

What would your expectations be on that build?

We’ve done a nice Dart 427 short block (Ford) for a client that had aluminum heads, it made around 450 with disappointment all around. AFR 225’s replaced those heads, now we’re in the mid 500’s, no other changes. Retail price difference at the time might have been $1500, money well spent.

We recently bought a 427 Dart short block (Chev) and filled it with a mild solid roller and an older set of Brodix Track 1 CNC heads, that build is knocking on the door of 600 HP, and it will live on the street running 91 pump gas.
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Re: Promaxx 225 heads

Post by PRH »

Mostly what I’m working with is Mopars.
A 416 is a pretty popular build for a SB........ but there are vastly fewer “larger” std platform cylinder head choices than for a SBC.

As a result, there are a lot of those motors being built that might seem like underachievers compared to what could be built without ever looking past a Summit catalog if you were building a SBC.

Many of those combos end up in the upper-400’s/low-500’s for HP, and would easily make more if there were a 220cc version of something like an Ede RPM head that flowed 280-ish and didn’t require the rest of the top end get replaced.

So, the under-500hp SB stroker isn’t that uncommon in my circle........ and some people spend enough on them to where they certainly don’t feel like they did a “budget” build.

I guess my point is, not everyone is trying to make over 600hp with their hot street or street/strip combo.

Just like not everyone building a similarly sized big block(440-460) is looking for that either.

If you’re shooting for about 600hp, and you come up short....... you probably just missed on the combo.

Pump gas SBC 422, AFR210, SV, HP950, easy on parts solid roller:
You do not have the required permissions to view the files attached to this post.
Somewhat handy with a die grinder.
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Re: Promaxx 225 heads

Post by BradH »

PRH wrote: Wed Jan 13, 2021 4:28 pm What’s the rest of the combo and how much power are you trying to make?
Maybe I missed it, but I don't see where the OP provided this additional information. Just saying it's a 434 SBC is still pretty wide open to interpretation.
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Re: Promaxx 225 heads

Post by BradH »

PRH wrote: Sun Jan 17, 2021 12:08 pm ...

I guess my point is, not everyone is trying to make over 600hp with their hot street or street/strip combo.

Just like not everyone building a similarly sized big block(440-460) is looking for that either.
Blasphemy! :lol:
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Re: Promaxx 225 heads

Post by rustbucket79 »

We recently finished a stroker 340 with a hyd roller, pump gas, M1 intake, Holley 750 Brawler and PW heads that made 480 HP, pretty decent combo that wasn’t cheap to build. We were also screwed by the Comp lifters by being unaware of the problem of not running a full shroud lifter body in a SBD block until it was on the dyno. #-o One would hope generic parts were sold to the public that actually function correctly. :x Oh well, lesson learned.

The AFR on that dyno sheet looks mighty crispy!
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Re: Promaxx 225 heads

Post by PRH »

The AFR on that dyno sheet looks mighty crispy!
I figured someone would comment on that.
That air turbine is a little optimistic on the flow, so it shows lean.

On the o2 it was in the upper 12’s/low 13’s.
Somewhat handy with a die grinder.
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Re: Promaxx 225 heads

Post by rustbucket79 »

PRH wrote: Sun Jan 17, 2021 3:17 pm
The AFR on that dyno sheet looks mighty crispy!
I figured someone would comment on that.
That air turbine is a little optimistic on the flow, so it shows lean.

On the o2 it was in the upper 12’s/low 13’s.
Brain fart, I was thinking that was an oxygen sensor reading. Some of our engines make their best numbers in the 14 to 15 to 1 range via the calculated A/F ratio.
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Re: Promaxx 225 heads

Post by PRH »

We recently finished a stroker 340 with a hyd roller, pump gas, M1 intake, Holley 750 Brawler and PW heads that made 480 HP, pretty decent combo that wasn’t cheap to build.
I’m going to assume, since there are no comments saying otherwise...... that you were satisfied with those results........ because they were in line with the expectations.

Where on the 427 SBF, 450hp resulted in nothing but disappointment.

You can look at that from either direction.......
The build was not aligned with the goals, or the goals were not aligned with the build.
If the real target was mid-500’s for power, and nothing but a head swap was worth nearly a 100hp gain....... then the way I see it, the first set of heads were not on the same page as the mid-500’s hp target.
I would have thought a flow test and some measurements would have indicated the heads weren’t up to the task.
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Re: Promaxx 225 heads

Post by rustbucket79 »

No flow bench here.

I’m sure you’re well aware the wants of customers in terms of using what they have or sticking to a budget, and nothing short of a dyno graph in their face is going to convince them otherwise. :lol:

Fortunately COVID-19 seems to have diverted travel and entertainment funds towards engines. =D> :mrgreen:

Have you come across issues with hydraulic roller lifters and LA engines?
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Re: Promaxx 225 heads

Post by Caprimaniac »

agree the promax would need some $ at a shop.
Would agree the heads are too small for a higher effort engine. The Promax would serve a moderate level of performance, even for weekend dragstrip acrion.

Cost-wise. Isn’t there quite a big gap promax+ stud rockers, and Weingartner- ported heads + shaft rockers? 3 or 4 x? IDK, but budget & performace level... Maybe something inbetween- like AFR heads w/ stud rockers? Something you can use out of the box- if you’re lucky?
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Re: Promaxx 225 heads

Post by WeingartnerRacing »

I have heads that don’t take shaft rockers.

The promaxx are a knock off of the Brodix ik heads. I ported several of those. They do not compare to a dragon slayer, profiler, or Afr head. This is because the later heads have a better design. You cannot port what’s not there.
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