ProMaxx and IMM aluminum small block LA heads

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A Mopar

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Good afternoon,

I am doing some research for my upcoming 340 build and have come across the heads in the links below. I can't find much on the internet about either of these and wanted to know if any of you have purchased and ran them on your engines. I've read some great things about IMM in numerous engine build articles, but I haven't seen any builds with their aluminum heads. My 340 is a 1972, and has the original J heads on it that will require a complete rebuild to be used. Rather than spending the money on them, I'm willing to ante up a little more $ for a modern, aluminum head. Any feedback would be appreciated.

Maxx 171 SB Mopar (Sold in Pairs) - PROMAXX Performance Products

IMMENGINES.COM
 
I think either head choice is great. Both have a good reputation. Others might give their thoughts. Better price than trick flows.
 
Those ProMaxx heads are box stock off shore chink heads.
Ow if you had found the CNC ported versions, I have those and they work well.

Weigh your price options and decide from there.
IMM is a poster here every now and again and is known for top notch excellent work.
My ProMaxx heads work was very well done. The off shore chink heads are handled by them and finished up here in the USA.
 
Pretty happy with the ProMaxx heads on my 360 LA, assembly quality is very good.

My2c.
 
rumblefish360 said:
Those ProMaxx heads are box stock off shore chink heads.
Ow if you had found the CNC ported versions, I have those and they work well.

Weigh your price options and decide from there.
IMM is a poster here every now and again and is known for top notch excellent work.
My ProMaxx heads work was very well done. The off shore chink heads are handled by them and finished up here in the USA.
Click to expand...
Is this Brian? IMM I mean
 
yes, should be Brian at IMM Engines. I do run a set of these cnc´d speedmaster castings touched up by him, no trouble at all, car running 10.65 at the moment. I´m happy with them, would buy again from IMM.

Michael
 
I got a bare set of these Promaxx CNC Shocker 185's haven't run them yet. They are just sitting in the living room.


promaxxperformance.com

Shocker 185 Mopar CNC (Sold in Pairs) - PROMAXX Performance Products

If your a small block Mopar enthusiast, you know your choices are limited. The Shocker 185cc is a full cnc option that flows over 285 cfm. Don't be stuck with over priced under performing cylinder heads. Let the Shocker 185 wake up your small block Mopar.
promaxxperformance.com promaxxperformance.com
 
I bought a set of the Promaxx castings (63cc, 171cc/77cc) from Todd at Marsh Performance back in 2017. Todd had them ported by Larry Smith and then Todd reassembled them and sold them to me as the Sidewinder heads. I have had no problems since the day that I received them. But Todd assembled them and checked them before he shipped them to me.

Since IMM (Brian) is a member, I would suggest discussing your options with Brian. If I was to purchase another set of heads, I would feel much better about buying them through another vendor (a shop) rather than just buying them from an online store. (Unless you are an experienced person who knows your way around these heads.)
 
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They sell a lot of Promaxx heads at the local machine shop…. Never heard of any big issues with them… lots street sbm builds pass through the place….the as cast heads seem to dyno in the 400-475hp range and the CNC shockers 500-580hp depending on the build…saying that if I lived in the USA I would buy the heads IMM sells just for the fact I always support small business when I can…
 
A Mopar said:
Good afternoon,

I am doing some research for my upcoming 340 build and have come across the heads in the links below. I can't find much on the internet about either of these and wanted to know if any of you have purchased and ran them on your engines. I've read some great things about IMM in numerous engine build articles, but I haven't seen any builds with their aluminum heads. My 340 is a 1972, and has the original J heads on it that will require a complete rebuild to be used. Rather than spending the money on them, I'm willing to ante up a little more $ for a modern, aluminum head. Any feedback would be appreciated.

Maxx 171 SB Mopar (Sold in Pairs) - PROMAXX Performance Products

IMMENGINES.COM
Click to expand...
If your 340 is mild, our import heads work really well. We sell them ready to bolt on.
 
Brian Hafliger said:
If your 340 is mild, our import heads work really well. We sell them ready to bolt on.
Click to expand...
Good Afternoon Brian, thanks for the feedback. I had planned on roughly 10.0-10.5:1 static compression, RPM air gap intake, this howards cam Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 2600 to 6200 Howards Cams CL710581-10 | Howards Cams, 1.5 ratio roller rockers, and a carb in the 750-800 CFM range. Will this camshaft's lift make the best of what your heads have to flow? I thought something between 500-.550 lift would be best for air flow in a street head but don't know the flow numbers on your heads so I wanted to ask your opinion. Should I target a zero deck height with the piston? Are your heads closed chamber?

Thank you.
 
A Mopar said:
Good Afternoon Brian, thanks for the feedback. I had planned on roughly 10.0-10.5:1 static compression, RPM air gap intake, this howards cam Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 2600 to 6200 Howards Cams CL710581-10 | Howards Cams, 1.5 ratio roller rockers, and a carb in the 750-800 CFM range. Will this camshaft's lift make the best of what your heads have to flow? I thought something between 500-.550 lift would be best for air flow in a street head but don't know the flow numbers on your heads so I wanted to ask your opinion. Should I target a zero deck height with the piston? Are your heads closed chamber?

Thank you.
Click to expand...
I like it. It’ll work really well. IMO, everything is well packaged.
 
A Mopar said:
Good Afternoon Brian, thanks for the feedback. I had planned on roughly 10.0-10.5:1 static compression, RPM air gap intake, this howards cam Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 2600 to 6200 Howards Cams CL710581-10 | Howards Cams, 1.5 ratio roller rockers, and a carb in the 750-800 CFM range. Will this camshaft's lift make the best of what your heads have to flow? I thought something between 500-.550 lift would be best for air flow in a street head but don't know the flow numbers on your heads so I wanted to ask your opinion. Should I target a zero deck height with the piston? Are your heads closed chamber?

Thank you.
Click to expand...
I recommend removing the heads, and bringing pistons on each side of the block to tdc and measure them against the deck to see if they are above or below the deck and by how much.
 
I thought he (Brian) was offering a bracket port job on those. At least that’s what he’s doing to mine. Don’t know the specifics of it, it’s been a while. But I gotta pay up. I’m ready Brian! Lol.
:)
 
i
A Mopar said:
Good Afternoon Brian, thanks for the feedback. I had planned on roughly 10.0-10.5:1 static compression, RPM air gap intake, this howards cam Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 2600 to 6200 Howards Cams CL710581-10 | Howards Cams, 1.5 ratio roller rockers, and a carb in the 750-800 CFM range. Will this camshaft's lift make the best of what your heads have to flow? I thought something between 500-.550 lift would be best for air flow in a street head but don't know the flow numbers on your heads so I wanted to ask your opinion. Should I target a zero deck height with the piston? Are your heads closed chamber?

Thank you.
Click to expand...
i have promaxx heads on my 318/390 stroker.....ported them a little...widened pushrod pinch....blended chamber/seat area...unshrouded inlet valve ... has a lunati hyd roller......232/[email protected] lift....port matched airgap...750 mech secondary....11-1 comp....excellent street combo....pulls hard from 2k to 6k....running 2600 stall 904...3.23 rear...if looking for more power......manifold and carb probably a bit small.....bigger cam moves powerband up....
 
n00blike said:
@Brian Hafliger Will you be offering the CNC version of the imported heads?
Click to expand...
I already do, but i only sell them on builds we do for now...I can't keep up with doing heads AND engines...I'm also working on some rocker kits for engines we build only for now, 1.65 ratio, cup adjuster, build around our import head (will also fit iron heads/edelbrock heads) and will work with pushrod oiling or std oiling. Hoping to have them available first of the year. If they work good, I'll consider selling them to the GP.
They won't be needle bearing, on center only rockers and only 1.65 ratio.
 
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