ProComp/Speedmaster aluminum heads

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i have a set of the cnc speedmaster heads on a 360 . I bought the heads bare and had the local machine shop i use do a performance valve job along with new valves and pac springs. They also put them on their flow bench and they did not set the world on fire.... The engine had another problem that did not allow us to get some good time slips in before the summer shut down in Vegas. Track reopens in September....

The engine has been repaired and camshaft changed out...I got a long list of things to do to the car but not sure if everything is going to get done as I want to run it at the TnT that Friday night. Trying to get roll bar in car with hope it runs fast enough to need it...LOL>...then the lightening of the car is needed for that 75 Duster....going to get rid of the heavy bumpers ...brackets...and shocks...putting a earlier front end on the car along with fiberglass hood and bumper....

  • and then i have another set of Speedmaster heads in Indio CA being ported...along with a set of Eddy heads....will be interested to see what the results are ....same porter and flow bench...apples to apples..
 
PRH said:
Do your heads have 11/32” stem valves?
The Speedmasters do.
I didn’t measure the length of the ones I had here, but a lot of that stuff uses SBC +.100” length(nominal 5.010”).

So, if that’s what you have, they might work.
The spring installed height is taller than stock heads, so those may not work.
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After all said and done I'd probably just leave my good running heads that I have on now alone and get new parts for the heads..
 
The SM SB Mopar unported heads flow about 250 ootb.

i have a set of the cnc speedmaster heads on a 360 . I bought the heads bare and had the local machine shop i use do a performance valve job along with new valves and pac springs. They also put them on their flow bench and they did not set the world on fire....
Click to expand...

From your other post on the other SM thread:

C0CEDB78-A3AF-4123-8B5E-40640DD317D8.png
 
70aarcuda said:
i have a set of the cnc speedmaster heads on a 360 . I bought the heads bare and had the local machine shop i use do a performance valve job along with new valves and pac springs. They also put them on their flow bench and they did not set the world on fire.... The engine had another problem that did not allow us to get some good time slips in before the summer shut down in Vegas. Track reopens in September....

The engine has been repaired and camshaft changed out...I got a long list of things to do to the car but not sure if everything is going to get done as I want to run it at the TnT that Friday night. Trying to get roll bar in car with hope it runs fast enough to need it...LOL>...then the lightening of the car is needed for that 75 Duster....going to get rid of the heavy bumpers ...brackets...and shocks...putting a earlier front end on the car along with fiberglass hood and bumper....

  • and then i have another set of Speedmaster heads in Indio CA being ported...along with a set of Eddy heads....will be interested to see what the results are ....same porter and flow bench...apples to apples..
Click to expand...
Do you have to channel your rear (73&up)fiberglass bumper so it doesn't stick out on the sides to much?
 
Why do you ask so many questions, on different threads, that have absolutely nothing to do with the thread title?

Speedmaster aluminum head thread...... and questions about a rear bumper?
:wtf:
 
PRH said:
Why do you ask so many questions, on different threads, that have absolutely nothing to do with the thread title?

Speedmaster aluminum head thread...... and questions about a rear bumper?
:wtf:
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Good question. LOL
There was only one question looking for one answer. With that said your question took up the space for that answer....
And now you've introduced the third subject which is off subject and is your fault, know how many fingers are pointing back at you? LOL
Let's not "panic"... LOL
I do want to keep this on the Speedmaster heads as just even like 70AARCuda has given us some great experience with them but yet not complete yet. I would love to hear somebody as you put it one of those 50% that just put them on and had some kind of catastrophe? You know kind of like the eagle crank breaking thing? There's no blowing up engines stigma around these that I'm finding?
Also when everybody pon page two started going off on how much they can be ported or not I tried to just keep the subject on the reliability and quality out of the box.
 
j par said:
Good question. LOL
There was only one question looking for one answer. With that said your question took up the space for that answer....
And now you've introduced the third subject which is off subject and is your fault, know how many fingers are pointing back at you? LOL
Let's not "panic"... LOL
I do want to keep this on the Speedmaster heads as just even like 70AARCuda has given us some great experience with them but yet not complete yet. I would love to hear somebody as you put it one of those 50% that just put them on and had some kind of catastrophe? You know kind of like the eagle crank breaking thing? There's no blowing up engines stigma around these that I'm finding?
Also when everybody pon page two started going off on how much they can be ported or not I tried to just keep the subject on the reliability and quality out of the box.
Click to expand...

two things,
1. try not to be a smart *** to someone that posts so much good info on the board
2. why don't you just send a PM about the bumper instead of junking up a good thread about heads...
 
cookietruck said:
two things,
1. try not to be a smart *** to someone that posts so much good info on the board
2. why don't you just send a PM about the bumper instead of junking up a good thread about heads...
Click to expand...
1. I always treat everybody the same. I say what's on my mind and people come to depend on that whether it's good or bad.
2. Unless you got something good to add about Speedmaster heads? You as well your just mucking up the thread with your bitching...
And just so it doesn't go unsaid, I damn sure appreciate everybody's experience and opinion with these heads...
 
j par said:
Good question. LOL
There was only one question looking for one answer. With that said your question took up the space for that answer....
And now you've introduced the third subject which is off subject and is your fault, know how many fingers are pointing back at you? LOL
Let's not "panic"... LOL
I do want to keep this on the Speedmaster heads as just even like 70AARCuda has given us some great experience with them but yet not complete yet. I would love to hear somebody as you put it one of those 50% that just put them on and had some kind of catastrophe? You know kind of like the eagle crank breaking thing? There's no blowing up engines stigma around these that I'm finding?
Also when everybody pon page two started going off on how much they can be ported or not I tried to just keep the subject on the reliability and quality out of the box.
Click to expand...


I broke an Eagle cast 4 inch stroker crank few years back
Know of a couple other guys that did too.
I started to lean on mine(10.30’s at the time off the foot) and it broke short while later
 
B3422w5 said:
I broke an Eagle cast 4 inch stroker crank few years back
Know of a couple other guys that did too.
I started to lean on mine(10.30’s at the time off the foot) and it broke short while later
Click to expand...
And with that said I've heard my local machine shops complain of their workmanship yet I haven't heard anybody come out and say these Speedmaster heads really messed up my engine? You would think after probably thousands sold, and if half of those are just put on right out of the box you would think there would be five or ten people out here saying that they had trouble?
 
I can get a good deal on bare ones that are CNC ported. So buy most everyone’s postings seems like I should get them. Is the S/M Procomp valves any good. What about springs etc. Kim
 
oldkimmer said:
I can get a good deal on bare ones that are CNC ported. So buy most everyone’s postings seems like I should get them. Is the S/M Procomp valves any good. What about springs etc. Kim
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I think the springs would be ok for a hyd cam.. wouldn't trust them for anything too wild.
As far as valves, They seem ok, look and measure identical to the edelbrock valve I bought as a replacement.
 
I appreciate that info too. I have a pair of CNC ported Speedmasters on the shelf at home that I want to just check out myself and use on a fIrly mild 360. That's what I was concerned about was the springs and valves.

Cley
 
I think if you portion carb cleaner in the ports and they don't leak and you take a few Springs off and the valves don't stick or rattle in the guides I think they would be pretty much good to go...
For mild use...
 
j par said:
I think if you portion carb cleaner in the ports and they don't leak and you take a few Springs off and the valves don't stick or rattle in the guides I think they would be pretty much good to go...
For mild use...
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I took apart boths sets of heads I had, nothing sticky, liquid held. I figured they were good to go. Not a fan of the helicoils pulling out in the cnc heads, but that may have been the combination of stuff I had, either way I wouldn't go too crazy with them.
 
The one thing I do not like about the speedmaster cnc was they did not remove the guides before they cut them. The intake guides end up cut away in the port and are only about 1.5 inches long.The guides did seem to be better quality than some of the ones I have messed with for sbc, sbf. They are also a standard [easy to find] size, .545 OD. I replaced guides in a set of sbf ones that were a .507 OD rather than the standard .502
 
j par said:
I think if you portion carb cleaner in the ports and they don't leak and you take a few Springs off and the valves don't stick or rattle in the guides I think they would be pretty much good to go...
For mild use...
Click to expand...
'finger wiggle mic' the valve at an estimated .350-.450 lift ..lol if you see it...its too much.
hand vac pump, like for brakes, make a rubber faced plate that can clamp or bolt on w/vac nipple and you can pull vacuum on the port 'port window side' valve closed to check if it seals enough to not burn in a few thousand miles.
 
Mopar Sam said:
The one thing I do not like about the speedmaster cnc was they did not remove the guides before they cut them. The intake guides end up cut away in the port and are only about 1.5 inches long.The guides did seem to be better quality than some of the ones I have messed with for sbc, sbf. They are also a standard [easy to find] size, .545 OD. I replaced guides in a set of sbf ones that were a .507 OD rather than the standard .502
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.
The ones I have don't look like they touched the guides.
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I wouldn’t count on the Speedmaster stuff to be super consistent from batch to batch........ but in this case at least....... it doesn’t appear the CNC heads get any more attention paid to the way the seats are done than the untouched ones.
Both get the one big wide angle......(and no, that’s not the hot ticket for flow or power).

D0D00483-4840-427A-80AF-912539B7EE90.jpeg


A5B73D47-0ACB-4878-B62B-9BFA8B32ED9C.png
 
PRH said:
I wouldn’t count on the Speedmaster stuff to be super consistent from batch to batch........ but in this case at least....... it doesn’t appear the CNC heads get any more attention paid to the way the seats are done than the untouched ones.
Both get the one big wide angle......(and no, that’s not the hot ticket for flow or power).

View attachment 1715375868

View attachment 1715375869
Click to expand...


Hard to tell from the pictures, but it looks like they took the top cut out when the opened up the chamber. I suppose that can happen with the seat cutter. The top cut is way too flat for my tastes. And I agree, the seats are way to wide. And who knows where they are on the valve.

That's why I'm not a fan of running anything out of the box. I wouldn't let a valve job like that out of the door.
 
PRH said:
I wouldn’t count on the Speedmaster stuff to be super consistent from batch to batch........ but in this case at least....... it doesn’t appear the CNC heads get any more attention paid to the way the seats are done than the untouched ones.
Both get the one big wide angle......(and no, that’s not the hot ticket for flow or power).

View attachment 1715375868

View attachment 1715375869
Click to expand...
Thank you! These are the kind of helpful comments that give us more information and knowledge about heads in general..
If I were to purchase these heads these would be the problems I would hope for. Something I could continue to upgrade as I have money maybe on a refresh get a better valve grind and so on.
I don't know if it's just me wanting to hear what I want to hear or I'm not reading you correctly, but what I hear you saying is if somebody has extremely reasonable expectations of these heads they won't be disappointed from the ones that you've seen and had experience with?
Fully understanding you as a professional who has this kind stuff in your shop all the time will probably opt for something else or at least having some "work" done to them?
 
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