Promaxx small bore heads
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Joined: Jul 2007
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From: Wilmington, De
I had bought a set of those when they were on sale during Black Friday. However, I returned them because I had ordered the 63cc chambers and I received the 59cc chamber versions. When I called, Promaxx checked and said that their site has a mistake and the heads are only available with 59cc chambers. They looked like a really nice set of heads in person. Too bad that I couldn't use them.
Interesting test, I hadn't looked at his vids since the cam challenge. It made very decent power, but I would like to see it tested with a stock LS3 ported intake as most with those heads will run that. A better ported 243 head would run next to it, having an otb Vic jr cathedral intake is choking it. I'm tempted to send him a set of Mast 243 CNC heads I have coming to slap on his dyno mule. I have seen some killer 243 heads lately, LME has a nasty set also that made 595hp on a midget cam 365. That's 1.63hp per cube, in theory a possible 665hp on his 408 at 12:1 comp pump gas. Hmmm
Interesting test, I hadn't looked at his vids since the cam challenge. It made very decent power, but I would like to see it tested with a stock LS3 ported intake as most with those heads will run that. A better ported 243 head would run next to it, having an otb Vic jr cathedral intake is choking it. I'm tempted to send him a set of Mast 243 CNC heads I have coming to slap on his dyno mule. I have seen some killer 243 heads lately, LME has a nasty set also that made 595hp on a midget cam 365. That's 1.63hp per cube, in theory a possible 665hp on his 408 at 12:1 comp pump gas. Hmmm
Supposedly the BTR canted valve LS head are supposed to be a game changer if they ever finally make it to market. Richard Holdener just did a video with Brian Tooley about them.
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Funny you mention, I saw the same video. Eh, I expected more, but maybe BT is playing it cool. Either way, glad i got my Brodix BR1 heads going on my 392. I would expect the canted valve stuff to totally kick ***, look at the LT #'s, but per his info in the video-not totally impressed.
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Verdad Gallardo Funny you mention, I saw the same video. Eh, I expected more, but maybe BT is playing it cool. Either way, glad i got my Brodix BR1 heads going on my 392. I would expect the canted valve stuff to totally kick ***, look at the LT #'s, but per his info in the video-not totally impressed.
Well, he has to make it passed the issues he mentioned and get them out to market first. I am definitely not a preponement of his, How ever I believe they could change things up. of course cost and availibilty will be a big thing too... the first sets are supposed to got to Porters. so be interesting to see what they end up on and how they preform.
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Joined: Apr 2006
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From: Pittsburgh
I watched a Richard Holdener video where he tested heads. Mast small bore rec heads made like 2 hp more than TEA ported 243 on a 402 or so stroker.
Last edited by wannafbody; Jun 3, 2025 at 10:14 PM.
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Joined: Mar 2012
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From: fbg, tx
I had a set of promaxx heads on a tbi squarebody, got the heads on a trade brand new for an bald eagles thing i didnt like too much. Anyway used ot with an carburetor edelbrock intake and an adapter to tbi some guy made i think he retired, i did the carb intake i stead of an edelbrock tbi intKe because the tbi ports even on the edelbrock unit are tiny. Anyway along with a custom chip and shorty headers, stock cam 2.73 gears went from a truck that would not do a one wheel burn out to save its life to going thru the meet at 10mph blipping the throttle and it making the wheels squeal. I wish i had gotten to do cam and gears on that thing before i sold it.
243's are tough to beat. I am anxious to see the Mast ones I have coming. GPIand LME also have a really good, developed program for them. I have had so many cyl heads go through my hands, it's interesting to see the trends and sorta what works, what doesn't. I will say this, the Brodix BR1's have the most unique bowl area of any cathedral head I have seen in person, and that includes a few different CNC 243's, a set of TEA TFS 220's and a few different sets of AFR's. The port entry on them is tiny, like a stock port, but the bowl area is massive and has an overall different shape than all the rest I have seen. They make power, a lot of turbo guys are running them in no prep/grudge but there is minimal info online about them. To my knowledge, I have not seen any dyno tests or track results from an NA build, so I may be the first.with mine. The only thing that is going to out run a cathedral on a small bore is a dedicated LS7 head and even that needs to be sized right to run right. I will say that the Mast LS3 heads are probably the pinnacle of that port design, since GPI stopped offering their canted Edelbrock LS3 head(note, the Mamo/AFR LS3 do seem good, would like to see a apples/apples of them vs Mast). Per conversation with them a while back, their LS7 small bore still bettered the canted LS3 head and both had developed ports. I think that says something. I find it interesting BTR is supposedly not offering a LS7 port on their new canted valve heads. To me, either there was either no gain doing it vs a std layout or not enough demand to warrant a different casting/version.
Last edited by DualQuadDave; Jun 4, 2025 at 09:26 AM.
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Joined: Feb 2025
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From: Texas
243's are tough to beat. I am anxious to see the Mast ones I have coming. GPIand LME also have a really good, developed program for them. I have had so many cyl heads go through my hands, it's interesting to see the trends and sorta what works, what doesn't. I will say this, the Brodix BR1's have the most unique bowl area of any cathedral head I have seen in person, and that includes a few different CNC 243's, a set of TEA TFS 220's and a few different sets of AFR's. The port entry on them is tiny, like a stock port, but the bowl area is massive and has an overall different shape than all the rest I have seen. They make power, a lot of turbo guys are running them in no prep/grudge but there is minimal info online about them. To my knowledge, I have not seen any dyno tests or track results from an NA build, so I may be the first.with mine. The only thing that is going to out run a cathedral on a small bore is a dedicated LS7 head and even that needs to be sized right to run right. I will say that the Mast LS3 heads are probably the pinnacle of that port design, since GPI stopped offering their canted Edelbrock LS3 head(note, the Mamo/AFR LS3 do seem good, would like to see a apples/apples of them vs Mast). Per conversation with them a while back, their LS7 small bore still bettered the canted LS3 head and both had developed ports. I think that says something. I find it interesting BTR is supposedly not offering a LS7 port on their new canted valve heads. To me, either there was either no gain doing it vs a std layout or not enough demand to warrant a different casting/version.
Sadly, I may have to switch topends... again😭. I was planning to run these on my 392 short block with Carbon PTR intake I also have, butttt I running into major fitment issues. Intake will def not work and I can't find a low style plastic intake that will let me turn the rpm I want(7400-8200). I am looking at a carb style intake w/ a 4500tb on top Going to borrow an intake and see how the fitment is. Plan B is go LS3 architecture w/ a Fast mid runner intake. I'm. hating my options, but is what it is I may have to build y spare LS2 block and throw this in my TBSS daily. Will know more in a week or so
Teching In
Joined: Feb 2025
Posts: 7
Likes: 2
From: Texas
Sadly, I may have to switch topends... again😭. I was planning to run these on my 392 short block with Carbon PTR intake I also have, butttt I running into major fitment issues. Intake will def not work and I can't find a low style plastic intake that will let me turn the rpm I want(7400-8200). I am looking at a carb style intake w/ a 4500tb on top Going to borrow an intake and see how the fitment is. Plan B is go LS3 architecture w/ a Fast mid runner intake. I'm. hating my options, but is what it is I may have to build y spare LS2 block and throw this in my TBSS daily. Will know more in a week or so