Small block Mopar ProMaxx head testing

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pittsburghracer

pittsburghracer

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My Son Matt sold his .040 over 360 shortblock out of his Duster a couple of months ago to a Friend. Needing a set of heads for it I have been researching ways for him to get the engine assembled and into a Dart that he recently bought. Knowing the Procomps (Speedmaster) had some issues I tried to find some info on the ProMaxx small block head that Jegs sells. With springs good for up to a 575 lift cam they cost slightly over 1400.00 a set shipped, app 200 plus dollars cheaper than Edelbrocks. I told him if he bought a set I would flow test them on my bench and strip on down to check it out for free. So far I have nothing but GOOD news for these heads and they put the Edelbrock heads to shame in both quality and flow numbers. The only issue I see so far is that the exhaust port flows almost EXACTLY the same as the Edelbrock head and they both have terrible (slow) air-speed on the exhaust side. He is going to install these as delivered so I can't wait to see the results. Air-speed at .500 lift on the exhaust port maxed out at 175-180 FPS and I good exhaust port should be at least 325 FPS and needs bell-shaped to get there. Both exhaust ports maxed out around 182-185 CFM and were checked without a ex flow pipe

-----Edelbrock--------------ProMaxx
--------Intake-----------------intake
.200-----128--------------------129
.300-----182--------------------184
.400-----215--------------------235
.450-----226--------------------251
.500-----233--------------------255-260 high air-speed
.550-----236--------------------260
.600-----242--------------------264
.650-----243--------------------270
.700-----243--------------------263-270
.750----------------------------263-270

As you can see by the numbers this BOTH ports need more volume. The air speed on the ProMaxx at the pinch at .400 lift is 300 average (center) at the pinch and 370 on the pinch turn. At .400 lift 365 FPS-390 FPS on the short-turn. At .500 lift at the pinch center 340-350 FPS and 401 FPS (pegged my gauge) at the pinch turn. At .500 the short-turn is way high at 390-401 FPS (pegged).
So far 4 valves were removed and the valve guide clearance is GREAT and a very nice at least 4 angle valve job done. The stainless valves look nice and come with a 30 degree backcut. I will be buying a couple sets of these later this year. One set with stock 2.02 valves and one set bare so I can go with a 2.08 valve
 
pittsburghracer said:
My Son Matt sold his .040 over 360 shortblock out of his Duster a couple of months ago to a Friend. Needing a set of heads for it I have been researching ways for him to get the engine assembled and into a Dart that he recently bought. Knowing the Procomps (Speedmaster) had some issues I tried to find some info on the ProMaxx small block head that Jegs sells. With springs good for up to a 575 lift cam they cost slightly over 1400.00 a set shipped, app 200 plus dollars cheaper than Edelbrocks. I told him if he bought a set I would flow test them on my bench and strip on down to check it out for free. So far I have nothing but GOOD news for these heads and they put the Edelbrock heads to shame in both quality and flow numbers. The only issue I see so far is that the exhaust port flows almost EXACTLY the same as the Edelbrock head and they both have terrible (slow) air-speed on the exhaust side. He is going to install these as delivered so I can't wait to see the results. Air-speed at .500 lift on the exhaust port maxed out at 175-180 FPS and I good exhaust port should be at least 325 FPS and needs bell-shaped to get there. Both exhaust ports maxed out around 182-185 CFM and were checked without a ex flow pipe

-----Edelbrock--------------ProMaxx
--------Intake-----------------intake
.200-----128--------------------129
.300-----182--------------------184
.400-----215--------------------235
.450-----226--------------------251
.500-----233--------------------255-260 high air-speed
.550-----236--------------------260
.600-----242--------------------264
.650-----243--------------------270
.700-----243--------------------263-270
.750----------------------------263-270

As you can see by the numbers this BOTH ports need more volume. The air speed on the ProMaxx at the pinch at .400 lift is 300 average (center) at the pinch and 370 on the pinch turn. At .400 lift 365 FPS-390 FPS on the short-turn. At .500 lift at the pinch center 340-350 FPS and 401 FPS (pegged my gauge) at the pinch turn. At .500 the short-turn is way high at 390-401 FPS (pegged).
So far 4 valves were removed and the valve guide clearance is GREAT and a very nice at least 4 angle valve job done. The stainless valves look nice and come with a 30 degree backcut. I will be buying a couple sets of these later this year. One set with stock 2.02 valves and one set bare so I can go with a 2.08 valve
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DSC01423.JPG
 
Good info. Thanks for posting, are the valves and related hardware quality ok for street/strip motor?
 
What about those funny lines in the intake ports....?
Casting impurities prone to crack later on or nothing to be concerned about?
 
Still more
gtsdude said:
Good info. Thanks for posting, are the valves and related hardware quality ok for street/strip motor?
Click to expand...

I Am really kinda impressed by how GOOD these look. The valves have numbers stamped on them so if I get a chance I will Google it to see what comes up. My Son ran 10.50's in his 3150 pound Duster with this shortblock and a set of Edelbrock heads I ported and installed a 2.05 valve in so although our Friend won't be going that fast it should run pretty good
 
stixx said:
What about those funny lines in the intake ports....?
Casting impurities prone to crack later on or nothing to be concerned about?
Click to expand...


Most heads come with those casting marks and are usually removed by porting work. I personally would never run a set stock because I do my own porting but these heads are very nice. Here are some pictures of the set of Edelbrock heads I bought last year. I already started porting on this set and they have the valve job opened for a 2.08 intake valve. Edelbrocks lack of quality has gone down-hill.

DSC01431.JPG


DSC01432.JPG


DSC01433.JPG
 
I notice most everyone tests the exhaust ports without a pipe and you mentioned the lack of air speed on the exhaust side. Since your car is never run without some sort of exhaust why wouldn't you install a pipe for the test and see what kind of difference that makes? I realize a header would most likely make it impossible to get on the flow bench but a single pipe for the port your testing should be able to be used I'd think. What do you think?
 
Thank you for the reply. The casting quality and the machining looks in fact a lot better than on the E'brocks.
 
Subscribed.
Thanks for posting this info. I'm still running iron heads and thinking of going aluminium.
 
fishy68 said:
I notice most everyone tests the exhaust ports without a pipe and you mentioned the lack of air speed on the exhaust side. Since your car is never run without some sort of exhaust why wouldn't you install a pipe for the test and see what kind of difference that makes? I realize a header would most likely make it impossible to get on the flow bench but a single pipe for the port your testing should be able to be used I'd think. What do you think?
Click to expand...

The main reason I or most guys don't use a pipe is what size pipe to use. you use a 1 5/8 header, Joe has a 1 3/4 header, Ron has a 1 3/4, I have a 1 7/8 header, Tim has a 2 inch, and Rambo has a stepped header. On most exhaust flow test it raises the flow around 20 CFM from my testing. On this head at .500 inch lift I placed a piece of 1 5/8 plastic pipe that I had sitting here and honestly it did nothing. As long as you know whether a pipe was used is all that matters to me when I look at any flow numbers. On the intake side you HAVE to use a radius plate or some guys use clay or even duct seal. I made lexan radius plates that are universal on the bolt holes. I honestly like the ProMaxx so far and with the lack of quality done on the small block Mopar heads hope to never buy another set and I buy quite a few heads. Saying that on any serious build the exhaust side needs some shaping and should require little time.
 
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I will try to buy a set of these ASAP but I don't see it happening till after race season (November). I will report back any findings.
 
pittsburghracer said:
The main reason I or most guys don't use a pipe is what size pipe to use. you use a 1 5/8 header, Joe has a 1 3/4 header, Ron has a 1 3/4, I have a 1 7/8 header, Tim has a 2 inch, and Rambo has a stepped header. On most exhaust flow test it raises the flow around 20 CFM from my testing. On this head at .500 inch lift I placed a piece of 1 5/8 plastic pipe that I had sitting here and honestly it did nothing. As long as you know whether a pipe was used is all that matters to me when I look at any flow numbers. On the intake side you HAVE to use a radius plate or some guys use clay or even duct seal. I made lexan radius plates that are universal on the bolt holes. I honestly like the ProMaxx so far and with the lack of quality done on the small block Mopar heads hope to never buy another set and I buy quite a few heads. Saying that on any serious build the exhaust side needs some shaping and should require little time.
Click to expand...
Appreciate the reply. Since you feel the exhaust port is lacking do you subscribe to the theory of using a split pattern cam and if so do you have a set ammount of degrees or vary by how much the port lacks? Hope you don't mind all the questions.
 
fishy68 said:
Appreciate the reply. Since you feel the exhaust port is lacking do you subscribe to the theory of using a split pattern cam and if so do you have a set ammount of degrees or vary by how much the port lacks? Hope you don't mind all the questions.
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I honestly know nothing about cam design and leave that up to the experts and honestly worry very little about exhaust flow numbers. I attended one of Darrin Morgans head porting classes and his beliefs were aimed more towards exhaust port air-speed. He said to aim for 325-350 FPS and the air WILL get out. Some of these ports are so choked up that they sound like a garbage disposal being turned on and off. This port did not have that sound but was VERY choked at 175 FPS. That being said its still a good head for 80-85% of the guys using them and would easily make 450 plus HP if not more. And questions do not bother me. I'm retired and if I'm not in the shop I dabble in the stock market so I'm on the computer watching the market every day.
 
pittsburghracer said:
I honestly know nothing about cam design and leave that up to the experts and honestly worry very little about exhaust flow numbers. I attended one of Darrin Morgans head porting classes and his beliefs were aimed more towards exhaust port air-speed. He said to aim for 325-350 FPS and the air WILL get out. Some of these ports are so choked up that they sound like a garbage disposal being turned on and off. This port did not have that sound but was VERY choked at 175 FPS. That being said its still a good head for 80-85% of the guys using them and would easily make 450 plus HP if not more. And questions do not bother me. I'm retired and if I'm not in the shop I dabble in the stock market so I'm on the computer watching the market every day.
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Ok. I just wondered what you thought about that. Unfortunately not a lot of guys I've dealt with measure the air speed, which I feel is an important part of testing a head. I hear ya on it'll get out. Got a lot of pressure helping it. Definitely sound like nice heads.

My wife works in a stock broker office so we could all find something to talk about, lol
 
Where did you get those flow numbers..my Edelbrocks flowed 249 on the intake@.500..not 233 as you have??..and with slight port worked flowed quite more,can't find my flow sheet,but 1/4 mile times don't lie as far as performance..and my Edelbrocks are cast/built in America..not China(cast) like the promaxx..
 
Wow, no tight valve guides. Thats good news. I just recently saw an out of the box pair of edelbrocks. They must have hired Stevie Wonder for quality control.



 
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stroked340 said:
Where did you get those flow numbers..my Edelbrocks flowed 249 on the intake@.500..not 233 as you have??..and with slight port worked flowed quite more,can't find my flow sheet,but 1/4 mile times don't lie as far as performance..and my Edelbrocks are cast/built in America..not China(cast) like the promaxx..
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I'm glad to hear you are happy with your edelbrock heads, I'm not. All I will say about flow numbers is that I have tested well over 15 sets of small block Edelbrock heads on my bench and never have seen numbers like you listed . Let me take a guess is it a super flow bench and have you ever checked calibration. This is the third flowbench I've owned and is calibration checked before every set of heads. No weather factors involved like on a liquid manometer bench

image.jpg
 
fratzog lover said:
Wow, no tight valve guides. Thats good news. I just recently saw an out of the box pair of edelbrocks. They must have hired Stevie Wonder for quality control.



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Thanks for posting the links. I finally took time today to watch them and there's LOTS of good info in the videos.
 
Resurrecting an old thread are you still happy with the heads? Are they just run on the drag strip? Just wondering about longevity. Did you ever research the valves to see what kind of quality. Thank you.
 
cawcislo said:
Resurrecting an old thread are you still happy with the heads? Are they just run on the drag strip? Just wondering about longevity. Did you ever research the valves to see what kind of quality. Thank you.
Click to expand...


Sorry I missed this. I didn’t go back and read this whole post but these heads belonged to a friend of mine. He finally put them on a street dart he has but no track times. He said it feels good though.
 
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