Direct Connection ( Mullen LA ) heads

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No air gaps allowed in group so the next best thing is a massaged Rpm intake !
Took intake to Killians Porting srvc in Warner Robbins GA ( Fine Fellow )
He welded all 4 inboard bolt holes up and re-drilled for W2 pattern then ported runners and per rules divider can be cut out but zero floor modifications allowed these are the finished results and a 1" spacer is allowed so it will be utilized as well .

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MOPAROFFICIAL said:
Those are his flow numbers for the mullen heads? Disappointing.
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It looks like the flow numbers are a little low on the CNC speed master heads posted for comparison, too. The effort on the Mullen heads does appear to be concentrated on the low lift flow. But it’s still preliminary as the valve seats need reworked to get them back to optimal. More to come, and many thanks to Chris for sharing! FWIW I’ll post up Mullen’s flow numbers from the Direct Connection “White Book” after I dig them out. To complicate matters there, the flow numbers are taken at a very low depression with the bench technology from 1975, so corrective formulas have to be applied for comparison. Even then, with such a large factor of correction at play, the margin of error will be on the high side for a true “apples to apples” comparison, but it does give some idea of what the heads flowed as delivered.
 
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Garrett Ellison said:
I forgot t

It looks like the flow numbers are a little low on the CNC speed master heads posted for comparison, too. The effort on the Mullen heads does appear to be concentrated on the low lift flow. But it’s still preliminary as the valve seats need reworked to get them back to optimal. More to come, and many thanks to Chris for sharing! FWIW I’ll post up Mullen’s flow numbers from the Direct Connection “White Book” after I dig them out. To complicate matters there, the flow numbers are taken at a very low depression with the bench technology from 1975, so corrective formulas have to be applied for comparison. Even then, with such a large factor of correction at play, the margin of error will be on the high side for a true “apples to apples” comparison, but it does give some idea of what the heads flowed as delivered.
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Thanks
 
1Badcolt said:
Thank you - yes correct Oem 360 castings
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Look at the pics.
They have offset pushrod holes, they are not OEM.
Dealer/factory performance part, yes.
I think the casting number is different than a regular 974 head, either way they've offset pushrod holes like a TA.
Thats why i say the numbers are disappointing. I and others can get 240's on average by .400 and 260s-270 @.500
They are very average heads. Historically significant, a collectors item. But for being an offset push rod head... they are barely worked.
Id use another head.
 
Looking at my white book and it’s an edition made before the development of the moved pushrod 360 castings. It lists flows for ported and “brazed and raised” T/A castings. I’ll post results over on the head flow chart, but all results are at 3 inches of H2O.
 
MOPAROFFICIAL said:
Look at the pics.
They have offset pushrod holes, they are not OEM.
Dealer/factory performance part, yes.
I think the casting number is different than a regular 974 head, either way they've offset pushrod holes like a TA.
Thats why i say the numbers are disappointing. I and others can get 240's on average by .400 and 260s-270 @.500
They are very average heads. Historically significant, a collectors item. But for being an offset push rod head... they are barely worked.
Id use another head.
Click to expand...
I would start out with those and optimize the rest of the package. I would worry about upgrading the heads until after that “ONLY IF THE NEED ARISES”. The rules cap the class with ballast addition at around the 6.90 mark. It would think they would still be adequate for that with 12.5-13:1 and 3070 pounds race weight.
 
I suspect the intake short turn rework isn’t very aggressive.
The port certainly “looks” like it would flow more than mid-250’s.
But...... you’re also into the “racing flow benches” thing to some degree.

I’m sure, like myself, most flow bench owners don’t consider numbers from other benches to be “apples to apples” with theirs.
Aside from possible variations in the bench itself, there is also the fact that different radius plates/devices are being used by the different shops, which can definitely impact the flow numbers.

The intake ports on the Mullen heads look to have more rework done to them than the TA heads I went through this spring........ yet if we try and compare the numbers as apples to apples........ they would appear to flow less.
“If” that’s how it would actually go down if tested back to back(and I’m not saying it would)....... I can only imagine the short turn on the Mullen head needed a little more attention.

6DDB9AF5-4A2C-46D0-8A3C-5FF48DE94B97.png


For comparison:
Lift—— in/ex
.100— 63/47
.200—130/99
.300—192/131
.400—237/148
.450—255/155
.500—259/159
.550—251/162
.600—253/165
.650—254/168

877CEF23-2EC4-42A2-83F2-E932A3790E7D.png


I guess what I’m saying is....... I’m giving Mullen the benefit of the doubt and that if I flowed that head on my bench....... I’d expect the numbers to be at least as good as the T/A head above.
 
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Garrett Ellison said:
I would start out with those and optimize the rest of the package. I would worry about upgrading the heads until after that “ONLY IF THE NEED ARISES”. The rules cap the class with ballast addition at around the 6.90 mark. It would think they would still be adequate for that with 12.5-13:1 and 3070 pounds race weight.
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They'll work fine im sure, 400's hp

Here is a thread of mine from long ago, with 1.88 and then 1.94 intake valves and numbers from them.
1wild&crazyguy said:
The numbers
.100-63.8
.200-128.2
.300-190.5
.400-229
.500-241.5
.550-241
.600-240.1

So it saturated some , but is not really backing up, and it picked up a good amount from .100-.500
Sorry I lagged on the update, I'm really busy
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1wild&crazyguy said:
The ex numbers after just mild bowl ,ssr , roof n guide blending...I also laid the floors casting bump back.
.200-103-80%
.300-146-76.6%
.400-169-73%
.500-180-74%
.600-192-79.6%
Click to expand...

They were just for a hotrod, 35 plym and have about half the work done to them than the TA heads and the mullen heads in this thread.
I'm not implying I'm better than Bob Mullen or anyone else ..just pointing out its knowing where to work
..and i think the sm #s are off.
 
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As for using them or not.......
the work that was done........was done for them to be used.
Not to lanquish on a shelf somewhere on static display.

I’d def use them.
 
I'm just going to say I really was hoping to see like... 300 CFM out of these things or something legendary.. from a legendary name , that's all.

I had high hopes that were crushed. Lol
I think i shed a tear when i saw the numbers, needed a hug.. lmao
 
PRH said:
As for using them or not.......
the work that was done........was done for them to be used.
Not to lanquish on a shelf somewhere on static display.
I’d def use them.
Click to expand...

Just don't hit'm with a piston or smash a valve impression into them. They'll be as worthless as all the 318 heads being melted into Hyundai's
 
PRH said:
I suspect the intake short turn rework isn’t very aggressive.
The port certainly “looks” like it would flow more than mid-250’s.
But...... you’re also into the “racing flow benches” thing to some degree.

I’m sure, like myself, most flow bench owners don’t consider numbers from other benches to be “apples to apples” with theirs.
Aside from possible variations in the bench itself, there is also the fact that different radius plates/devices are being used by the different shops, which can definitely impact the flow numbers.

The intake ports on the Mullen heads look to have more rework done to them than the TA heads I went through this spring........ yet if we try and compare the numbers as apples to apples........ they would appear to flow less.
“If” that’s how it would actually go down if tested back to back(and I’m not saying it would)....... I can only imagine the short turn on the Mullen head needed a little more attention.

View attachment 1715637388

For comparison:
Lift—— in/ex
.100— 63/47
.200—130/99
.300—192/131
.400—237/148
.450—255/155
.500—259/159
.550—251/162
.600—253/165
.650—254/168

View attachment 1715637392

I guess what I’m saying is....... I’m giving Mullen the benefit of the doubt and that if I flowed that head on my bench....... I’d expect the numbers to be at least as good as the T/A head above.
Click to expand...
U nailed it , figures shown are on Conservative side - guy doing work doesn't have Roush type flow equipment but is a Very competent individual
better info as soon as its available !
 
My Mullen heads weren’t from the catalog, no offset pushrods. They were sent to his shop to be done. Not sure when, I was told early ‘70’s??
They are 63cc. 2.02 valves.
Photos:
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20-ish years ago someone sent me some ported stage VI heads to look over/go through.

The ones MP was selling that were done by Arrow racing engines.
They were still new in box.

Granted, stage 6’s were as bad as I’ve ever seen for poor manufacturing QC...... but those ported MP heads were absolutely nothing special..... at.....all.
And they had some of the typical stage 6-ism’s....... that hadn’t been addressed one bit.

The bottom line is........ heads that are being sold out of a catalog(especially from back before CNC porting existed), are built/reworked based on a fixed price point(yet advertised for a pretty high MSRP).

While I’m still giving these Mullen heads the benefit of the doubt that they would exceed 253cfm on my bench....... I also wouldn’t be shocked if they didn’t.
 
Any good sbm exh port has it going flat and down just before the exit on the low side.
I remember that being one of the first things I noticed as a youngster checking out other people's work and learning.
 
MOPAROFFICIAL said:
I'm just going to say I really was hoping to see like... 300 CFM out of these things or something legendary.. from a legendary name , that's all.

I had high hopes that were crushed. Lol
I think i shed a tear when i saw the numbers, needed a hug.. lmao
Click to expand...

Its ok - Get the wife to feed you grapes and rub lotion on your feet tonight and u will be ok !
One good thing pertaining to head flow is reduced CI so maybe overall they will be adequate !
 
If Mullen was flowing at 3 inches of water column (I thought it was 10 but I think wrong a lot) the conversion to 28 inches is pretty useless like GE a mentioned above.

The air column at 3 inches behaves completely different than what it does at 28 inches. O any mathematical formula will be at best a close approximation.

If a port looks god at 3 inches it may suck at 10, look better at 24, go straight to hell at 28 inches and raising the test pressure higher is a crap shoot.

I tested everything at multiple pressures, to the point of testing the same lift at 4 or 5 different pressures.

You start to see trends that develop, and usually the trends will tell you to do things that are contrary to conventional wisdom.
 
1Badcolt said:
Its ok - Get the wife to feed you grapes and rub lotion on your feet tonight and u will be ok !
One good thing pertaining to head flow is reduced CI so maybe overall they will be formable .
Click to expand...
Ill make it. Lol
Of course make a head "big" by shrinking the CID.
 
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