Author Topic: BBM head flow  (Read 11300 times)


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Re: BBM head flow
« Reply #3 on: June 23, 2014, 06:52:38 AM »
I obviously have a bias.

Given all the internet noise regarding the BBM head I decided to accumulate the various flow numbers being tossed about into a single spreadsheet.  At first glance it looks to be a reasonable part, but certainly not as earth shattering as some have been claiming. 

Hard to make a true comparison to my casting without port volume and cross section data - but from what I can see I ain't getting too scared yet.  Looks like the Americans are still pretty competitive...  His original "factory rep" postings on the Network54 forum have been deleted.  Those were the ones where he said that good quality castings could not be made in the US, and he scoured the world before deciding on the best possible casting source - which just happened to be his employer.

Flow benches vary by a fair amount, everybody's flow bench is "tight" and everybody else's is inflated -just like dynos.  I think we are in pretty good shape here considering that I know who designed mine and I know where they are made and machined....

Some older flow data comparing my heads to off the shelf Edelbrocks, our own Stage X iteration of the Edelbrocks with larger valves, our own CNC ported Edelbrocks, and my "kinda new" castings.

Drew Pojedinec

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Re: BBM head flow
« Reply #2 on: June 21, 2014, 05:48:25 PM »
Thanks Joe!  Great information.


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BBM head flow
« Reply #1 on: June 20, 2014, 07:52:05 PM »
With permission:  I acquired a set of the BBM aluminum heads for the FE, and did a cursory valve job on a Serdi with multi-angle seats, back cut intake valve of 2.080", and custom radius exhaust seat with 45* valve face for a 1.600" exhaust valve.  I went with these sizes to start off the flow expectation from smallest to larger on later tests.  The guides were so hard that they had to be honed to size, since a reamer would not work well with the hardness.  It took nearly 2 hours just to hone the guides to size for the 11/32 valve stems.  Here are the flow values for the initial testing of completely stock ports.

.100      63.98
.200     136.09
.300     207.18
.400     234.61
.450     243.85
.500     252.79
.550     261.14
.600     267.10
.650     274.25
.700     280.22
.750     284.99

.100      52.00
.200      98.30
.300     129.99
.400     149.99
.450     161.98
.500     166.84
.550     173.32
.600     178.18
.650     181.42
.700     183.69
.750     184.66/2" pipe 200.86

Super Flo 600 #6729 @ 28" 70* 38% Humidity in airconditioned room, calibration check completed.  The valve seats were proud in several ports, and the flow was noisy at low lifts.  I am sure the exhaust will come up with larger size valves, as will the intake.  This was just a preliminary test as cast with CJ size intake valve and a slightly larger exhaust valve than a standard 390.  I will be testing with 2.100/1.660 next as time permits, and ultimately 2.190/1.710, and then fully hand ported.  Since many have followed different heads' flow sheets over the last several years, it will be interesting to compare on the same machine with same operator, and same porter.  As always, I just post what I get on my machine as truthfully as possible and under as similiar circumstances as possible.   Joe-JDC