35% off SpeedMaster

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gzig5 said:
I love how little or inaccurate the information on some of these import heads is. Says that they are flowed on a Superflow SF600 but there is no flow data provided? Apparently these are pushrod oiled, not that they make a substantial effort to point that out.
Click to expand...
they aren't pushrod oiled... the info in pretty messed up.
 
Many tnx, sk. Sounds like the same valves as the Edelbrocks....

Next question: Do the heads use the same 1.800" installed spring height as the Edlebrocks?
 
I have a set of Speedmaster SBM heads in the shop for a lookover.
All they wanted done was to make sure they were serviceable...... they’re not here for any performance enhancements.

These are assembled heads, part number PCE281.2146, set up for flat tappet cams.
They came with dual springs w/o damper, 10* retainers & locks, and steel jacketed seals.
I pulled them apart, checked the spring installed height, guide clearance, and valve seat run out.
Seats were not machined in a way that benefits air flow, but the concentricity was good, and the guides were all about .0022” clearance.
The only “issues” that could have caused some headaches had they been bolted on “ootb”, was two of the springs were down about 15lbs seat pressure, and most of the seals fit poorly(quite loose) on the guides.
Even though the springs are duals, the rate is fairly low.
125 on the seat, about [email protected] lift.
They have quite a bit of travel though, so I just shimmed the two that were low up to 125lbs.
I also replaced the seals, which fit nice and tight...... so the poor fit was in the seals, not that the tops of the guides were sized incorrectly.

Plopped one on the bench, “just to see”.
4.00” bore, 28” test pressure, no tube on exhaust:
Lift——in/ex
.100— 60.4/48.8
.200—120.4/97.6
.300—176.8/134.2
.400—221.4/153.7
.450—230.7/159.8
.500—240.1/164.7
.550—250.5/166.4
.600—250.5/168.3
.650—251.3/168.3
.700—253.1/168.3

51151228-97F2-4D73-8295-E11F7DEB6DB9.jpeg


223A58DE-3FE7-44BC-92E5-D694D54BC461.jpeg


3875CEE9-5545-4F66-AA62-65C9BD7D3FA0.jpeg
 
PRH said:
I have a set of Speedmaster SBM heads in the shop for a lookover.
All they wanted done was to make sure they were serviceable...... they’re not here for any performance enhancements.

These are assembled heads, part number PCE281.2146, set up for flat tappet cams.
They came with dual springs w/o damper, 10* retainers & locks, and steel jacketed seals.
I pulled them apart, checked the spring installed height, guide clearance, and valve seat run out.
Seats were not machine in a way that benefits air flow, but the concentricity was good, and the guides were all about .0022” clearance.
The only “issues” that could have caused some headaches had they been bolted on “ootb”, was two of the springs were down about 15lbs seat pressure, and most of the seals fit poorly(loose) on the guides.
Even though the springs are duals, the rate is fairly low.
125 on the seat, about [email protected] lift.
They have quite a bit of travel though, I just shimmed the two that were low up to 125lbs.
I also replaced the seals, which fit nice and tight...... so the poor fit was in the seals, not that the tops of the guides weren’t sized correctly.

Plopped one on the bench, “just to see”.
4.00” bore, 28” test pressure, no tube on exhaust:
Lift——in/ex
.100— 60.4/48.8
.200—120.4/97.6
.300—176.8/134.2
.400—221.4/153.7
.450—230.7/159.8
.500—240.1/164.7
.550—250.5/166.4
.600—250.5/168.3
.650—251.3/168.3
.700—253.1/168.3
Click to expand...


Good info. Thanks
 
Basically your average aluminum head flow.
Factory iron numbers through .300 then 25-30cfm more @.400 and above. 308s atm flow the same.
Those Manley seals are drag stuff, they don't do a great job keeping the oil off the back of the valve head on a street motor.Too bad the customer doesn't want a little short turn work.
 
Last edited:
MOPAROFFICIAL said:
Basically your average aluminum head flow.
Factory iron numbers through .300 then 25-30cfm more @.400 and above. 308s atm flow the same.
Those Manley seals are drag stuff, they don't do a great job keeping the oil off the back of the valve head on a street motor.Too bad the customer doesn't want a little short turn work.
Click to expand...
Where, and approx how much, would that improve things?
 
nm9stheham said:
Where, and approx how much, would that improve things?
Click to expand...


Widen the pinch some, (don't go crazy) Straighten out the common wall, widen the short-side and shape, valve job, check throat to valve size ratio, back cut valves if not already done, clean-up chamber. Remove all rough casting in port left from casting. Done right you will easily be between 285-295 cfm. After that you better know what you are doing.
 
So checking out Speedmaster website, on the assembled heads, there are 3 versions it seems. Ranging from apx. $1200 to $1800 in price. Will the $1200 version be ok for a 400hp '73 340 with 2316 pistons?
 
PRH said:
I have a set of Speedmaster SBM heads in the shop for a lookover.
All they wanted done was to make sure they were serviceable...... they’re not here for any performance enhancements.

These are assembled heads, part number PCE281.2146, set up for flat tappet cams.
They came with dual springs w/o damper, 10* retainers & locks, and steel jacketed seals.
I pulled them apart, checked the spring installed height, guide clearance, and valve seat run out.
Seats were not machined in a way that benefits air flow, but the concentricity was good, and the guides were all about .0022” clearance.
The only “issues” that could have caused some headaches had they been bolted on “ootb”, was two of the springs were down about 15lbs seat pressure, and most of the seals fit poorly(quite loose) on the guides.
Even though the springs are duals, the rate is fairly low.
125 on the seat, about [email protected] lift.
They have quite a bit of travel though, so I just shimmed the two that were low up to 125lbs.
I also replaced the seals, which fit nice and tight...... so the poor fit was in the seals, not that the tops of the guides were sized incorrectly.

Plopped one on the bench, “just to see”.
4.00” bore, 28” test pressure, no tube on exhaust:
Lift——in/ex
.100— 60.4/48.8
.200—120.4/97.6
.300—176.8/134.2
.400—221.4/153.7
.450—230.7/159.8
.500—240.1/164.7
.550—250.5/166.4
.600—250.5/168.3
.650—251.3/168.3
.700—253.1/168.3

View attachment 1715297158

View attachment 1715297159

View attachment 1715297160
Click to expand...

Did you happen to measure the installed stem height? Was it anywhere near 1.917 or middle range spec?
 
The installed height on the ones I had here was about 1.840, with about .060 worth of shims under the springs.
 
chrispy1971gtx said:
So checking out Speedmaster website, on the assembled heads, there are 3 versions it seems. Ranging from apx. $1200 to $1800 in price. Will the $1200 version be ok for a 400hp '73 340 with 2316 pistons?
Click to expand...

If your pistons have positive deck height, you’ll have to take that into consideration for which heads and gaskets you use.
 
Didn’t measure the stem height, or the valve length, but that type of head typically uses a SBC +.100 valve(nominal 5.010”).

If you look at the pic of the springs/retainers installed you can see the tips are pretty proud of the retainers...... I’d say the tip height is well higher than 1.920.
 
PRH said:
Didn’t measure the stem height, or the valve length, but that type of head typically uses a SBC +.100 valve(nominal 5.010”).

If you look at the pic of the springs/retainers installed you can see the tips are pretty proud of the retainers...... I’d say the tip height is well higher than 1.920.
Click to expand...
The high end 1.937 or so, that will make the rocker tips rollout worse than already is.
If they were spending on them...I'd get a kit from b3racing , but if not and they were mine...I'd cut them all some or to the mid spec, as tedious as that is.
 
pittsburghracer said:
Widen the pinch some, (don't go crazy) Straighten out the common wall, widen the short-side and shape, valve job, check throat to valve size ratio, back cut valves if not already done, clean-up chamber. Remove all rough casting in port left from casting. Done right you will easily be between 285-295 cfm. After that you better know what you are doing.
Click to expand...
Does any one on here have experience massaging these? And How much would a set with the above work and some 2.05 valves run?
 
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