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any buddy use ProMaxx Performance 9440 - ProMaxx MAXX Series Big Block Chrysler Aluminum Cylinder Heads Details

Big Block Chrysler 210cc/295+ CFM Additional Cylinder Head Specifications
Valve Angle: 15° Valve Seal Material: Viton Spark Plug Type: Angled Retainer Material: Steel Maximum Spring Lift: .600" Hydraulic Flat Tappet think about use them on 66 440 factory steel crank factory steel rods lighten polish with JE or ROSS pistons full floating pins

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i'm not certain but looked around a little bit and am inclined to believe they're imported castings, i could be wrong. that said if they are imported for that money i'd pony up the rest and buy a USA made head but that's just me. they actually cost more than the 75cc e street heads with the racer discount

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You have a PM

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for price cant beat it

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Promaxx doesn't buy castings from the guys selling Sidewinder heads, that much I know.
RPM heads and Stealth heads both flow much less than advertised on a calibrated bench. Sidewinder heads will out flow those two castings out of the box.
I don't know how these Promaxx compare
Keith

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The Sidewinder heads can be bought through Todd at CompWedge Engines, or I can get them. There are a couple other builders selling them also . They really are a nice part .
I have a build in the works with a set now. More consistent port shape and size when compared to other brands I have used.
Keith

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Guys as far as I know the Promax and the sidewinder are the same casting. Robin they will not touch a Victor. These are much more akin to the RPM. Todd

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RPM heads and Stealth heads both flow much less than advertised on a calibrated bench.

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A truer statement on Moparts I have not heard

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I believe in either this month or last months Mopar Muscle they did a 451 build and use the ProMax heads. I dont remember all the details but I think they flowed around 340 on the intakes ? I know the eng made very good hp (like 675 I think) and torque. I will try to look it up when I get a chance. Ron

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I believe in either this month or last months Mopar Muscle they did a 451 build and use the ProMax heads. I dont remember all the details but I think they flowed around 340 on the intakes ? I know the eng made very good hp (like 675 I think) and torque. I will try to look it up when I get a chance. Ron

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They used ProComp heads (Victor copy?): http://www.moparmusclemagazine.com/techarticles/1411_randy_maliks_452ci_low_deck_wedge_mopar_engine/

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What do out of the box standard port victors flow? I know they are designed for something different than sidewinders but how do they compare?

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Remember a few years ago, a new US cylinderhead company called Patriot? They staked out the lower edge of the smallblock chevy market, made a decent aluminum head which got a lot of press because it was good but inexpensive.

Somewhere along the way they were bought and renamed as ProMaxx.

As their sbc and sbf heads were pretty good, I would guess that their BBM heads would be good too.

R.

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Was seriously thinking about a pair of 440 Source Steaths but after reading about the Promaxx and Sidewinder heads now I got some more home work to do.Anyone ran these with the Edlebrock Victor intake yet?

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I believe in either this month or last months Mopar Muscle they did a 451 build and use the ProMax heads. I dont remember all the details but I think they flowed around 340 on the intakes ? I know the eng made very good hp (like 675 I think) and torque. I will try to look it up when I get a chance. Ron

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676 hp with a cast 440 crank and stock 400 rods!
Hows that for a cheap bottom end?

Even with the "short" 6.358" rods, R/S ratio still calcs out at 1.696.

The ProComp cylinder heads were done by MCH and were pretty trick, flow in the mid 300s. That's where the power came from.

R.

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Use extreme discernment when reading this article. J.Rob

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Does anyone know if the pushrod clearance is any better on these than the 440Source Heads? We had several hours of grinding to get the pushrods to clear on my 383.

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Making room for push rods is normal on any aftermarket head unless you use a 5/16ths--which with hyd cams is fine-- but most builds will require a 3/8ths pushrod--any Mopar requires lots of time spent--shimming each pair rockers--getting it just right--centered on valve as close as possible while clearing the head and all the while winding up with proper side clearence per pair on rockers--each pair may be shimmed different--that is Normal--grinding for more room is very normal operation an any build. Wait until you get smart and put 1.6 ratio rockers on with a big cam--Lots o grinding there!!
I have been dynoing plain old 440 street engines with Sidewinder heads--looks like with bigger hyd cams they are doing easy 530 range on simple flat top pump gas combos--these have been with STAMPED stock rockers as well.
Low you say?? I say cheap and simple and enough HP and monster TQ to rip quarter pannels off.
90% of customers have NEVER had any real HP and over 500 REAL HP makes them shake after a ride--as it SHOULD! The quest for all these 600-700HP street engines is a laugh to me--you can't hook it up--they are a PIA to drive with all that converter , gear etc--Street driving a race engine has never been as fun as it is rated--like driving the Zamboni on a skating rink.
Just my two cents worth--Call Todd at Marsh, get some Sidewinders and enjoy not paying the extra $600 for Edelbrocks and going same speed.
Same head everywhere no matter the name--buy a skid of them and you can name them anything you want--we are LUCKY to have a quality head that is less than the others out there--Source heads are brittle castings to me--these heads have the guides centered Right ON and are all CNC finished--I have been using them like popcorn and Todd at Marsh Performance has Kept them coming!!!!

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Sound promising so far and I`m here to tell ya driving 600-700 hp engines has been the norm for me for MANY years w/out any draw backs to me and AGAIN more myths de-bunked. I have an 8" 5000+ vert, spool and yada yada.............some like it, some don`t........some can handle it and some can`t but what fun w/MORE to come.............

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... The quest for all these 600-700HP street engines is a laugh to me--you can't hook it up--they are a PIA to drive with all that converter , gear etc--Street driving a race engine has never been as fun as it is rated--like driving the Zamboni on a skating rink.

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Well, my car drove pretty much the same on the street when it ran 10.5s as it did when it ran 12.0s. Not just my opinion, but that of a friend of mine who has seen the car evolve over most of the last 20 years I've owned it.

I don't race on the street, but if I wanted it to hook on the street( ), I'd take a different approach than what I've done to date.

You may now return to your regulary scheduled program about these new budget heads.

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... The quest for all these 600-700HP street engines is a laugh to me--you can't hook it up--they are a PIA to drive with all that converter , gear etc--Street driving a race engine has never been as fun as it is rated--like driving the Zamboni on a skating rink.

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Well, my car drove pretty much the same on the street when it ran 10.5s as it did when it ran 12.0s. Not just my opinion, but that of a friend of mine who has seen the car evolve over most of the last 20 years I've owned it.

I don't race on the street, but if I wanted it to hook on the street( ), I'd take a different approach than what I've done to date.

You may now return to your regulary scheduled program about these new budget heads.

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I should have said Most not all
Sure there are guys that have evolved a car/combo over the years and it is what hot rodding is all about--That is a thing of beauty and to be admired
I just see so many combos that are not that well organized or sorted and are really just race car set ups on street car paint jobs and thus my statement--BTW I built a few of the unruly type when I started--
These days FI etc has sure made things better and all the big CI with mild cam and 3.23 rear gears --sweet new converter science--all adds up to some magnificent street machines that will run as well as our race cars did 20 years ago
again....
On the street I prefer my Hemi Ram pick up and on the track I am LOVING my Front engine dragster--Both do what is asked of them really well
After a pass in the dragster you KNOW you were in a race car that was stinking fast--and the truck has comfortable room for all the junk I carry around with me and a big console storage

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We recently did a maxed out full port on the Sidewinders ( same head I believe) and the results were right at 313 CFM intake on a Very correct , calibrated, stingy bench.
I am sure as time rolls on and more heads are whittled on that it will get better but honest, this is a street strip head not intended to go toe to toe with Victors, Indys etc
It is designed to be an Edelbrock killer and I guess you need a "Sidewinder" to shoot at Stealths?
So far---I have done several strong street engines with these heads --ZERO issues--I love the casting quality and the seats and guides are some of the best on the market --ports are more equal on these than other brands as well.
We have a regular old 440 flat top headed to the dyno soon with a set and a hyd cam so will report.
I love the quality for the $$ and feel like they are the best answer out there for a street/strip big block--way less than Edelbrocks and IMO better overall quality than everything else.
Want to race hard and go really fast? Sure, there are better choices but these heads will do anything an Edelbrock Performer head can for LESS $$ and at 313 CFM--Surprise many a bracket racer!!
Now...spending the loot it takes to get 313 CFM range--on a street head? Well... that is up to the individual, and a real race head may be better choice but...the heads are VERY capable of some Serious HP!
So far....I LOVE these heads!

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So now that we're talking to someone much closer to the manufacturer, here's the question I've been dying to ask:
Could you build a head with a modern combustion chamber? Look at the AFR smallblock chevy heads for inspiration. Or basically any other modern aftermarket Wedge head.

Thanks,
R.

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Crabman and Dunnuck, I know each engine could be different, but in general, what is the pushrod clearance like with these heads and 3/8" pushrods and 1.5 rockers? Have you had to grind for clearance or not had to grind for clearance in most cases? Thanks!

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Crabman and Dunnuck, I know each engine could be different, but in general, what is the pushrod clearance like with these heads and 3/8" pushrods and 1.5 rockers? Have you had to grind for clearance or not had to grind for clearance in most cases? Thanks!

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I did not hear anything about the clearance. If there is before, there is not afterwards.

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