How much HP from SBM ProComps? Well... 670HP!

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MRL Performance

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Ok, so I have been using these ProComp SBM heads for about 1 1/2 years now. I think I got a pretty good handle on them. As with any head or part, they could use a bit of massaging to make them work real good. So here is our latest attempt. Im going out on a limb here and going to claim the MOST POWER MADE TO DATE WITH THESE HEADS, N/A NO FORCED INDUCTION, NO NOS!

This is a re-do from an engine we built last year. Customer wanted more power so we pushed it up a bit. here is the run down.

360 magnum R block
4.060 bore
3.825 stroke
6.250 rod
From the top down.........
1050 Dominator
Super Victor, ported in house
T&D roller rockers
Procomp heads, flowing 312/230
Custom Ractec flat top pistons 12.2 to 1
Custom Lunati roller cam, sorry no specs. I can tell you high 270's and mid .600's
MRL Pro PLUS soild roller lifters
3/8 pushrods
PEP I beam rods
HP bearings
Billet timing set w/tensioner
Mallory 32 series dist 34* total
Custom made wires Champion plugs
Kevko oil pan
Melling HV oil pump
Bla bla bla

Now for the fun stuff.

Torque, its whats for dinner. It peaked at 564TQ at 5400rpm. But it had 530 from 4600-6650. Hell at 7200 it still had 475TQ!!!!!

HP, its what kills the Chevys. Peak was 670HP 6550rpm. It made 600+ from 5600rpm on up. Still making 650HP at 7200rpm.

BSFC was .395-.459 the entire run and still had a A/F ratio of 11.3-11.9. I wanted to tune more but ran out of dyno time. Valve lash was best at .025I .026E. Ran a 2" tapered spacer fro the Dominator.

So there you have it 670HP with a 396ci SBM and those damn ProComp heads. BTW they are out of stock and will not have any until November.
 
Is all the massaging available with a CNC program? What's the total $$$ to set them up for the max HP?
 
It's all hand work. Won't know on price for a set until they get them back in stock. I have been told there will be a price increase, but they are still less expensive than RPM. Fully done up RPM heads ready to go with roller springs are $3000 or more. Procomps from us will be a lot less than that.
 
Stout little small block. Nice job.
 
I hope you send that update to the magazines!
 
!! DAMN !! I'd line to be able to afford one of those.

Naw, I' juz' git maself in trouble.

foghorn_leghorn.jpg
 
Nice one!!! 1.7 x cubes with PC heads, and at a midland rpm.......Yep, i'd say you did good! :D
 
Impressive for an LA small block , close to 700 hp is unreal .
 
Those are some pretty sharp numbers.
Out of stock probably means more have to be cast.
Lets hope they don't try to cut corners, save money, or suffer brain fade and wind up with a run of heads which aren't fit for purpose like the batch of crosswinds doing the rounds.........
 
valvebounce said:
those are some pretty sharp numbers.
Out of stock probably means more have to be cast.
Lets hope they don't try to cut corners, save money, or suffer brain fade and wind up with a run of heads which aren't fit for purpose like the batch of crosswinds doing the rounds.........
Click to expand...

lol!
 
This engine going in to a drag car? Will we get to hear 1/4 mile times to back up the hp claims? Seems like it should be a stout combo in the right chassis setup.
 
Awesome build Mike-I'd also like to see this thing screaming down the 1320 in a properly set up chassis.
 
MRL Performance said:
Ok, so I have been using these ProComp SBM heads for about 1 1/2 years now. I think I got a pretty good handle on them. As with any head or part, they could use a bit of massaging to make them work real good. So here is our latest attempt. Im going out on a limb here and going to claim the MOST POWER MADE TO DATE WITH THESE HEADS, N/A NO FORCED INDUCTION, NO NOS!

This is a re-do from an engine we built last year. Customer wanted more power so we pushed it up a bit. here is the run down.

360 magnum R block
4.060 bore
3.825 stroke
6.250 rod
From the top down.........
1050 Dominator
Super Victor, ported in house
T&D roller rockers
Procomp heads, flowing 312/230
Custom Ractec flat top pistons 12.2 to 1
Custom Lunati roller cam, sorry no specs. I can tell you high 270's and mid .600's
MRL Pro PLUS soild roller lifters
3/8 pushrods
PEP I beam rods
HP bearings
Billet timing set w/tensioner
Mallory 32 series dist 34* total
Custom made wires Champion plugs
Kevko oil pan
Melling HV oil pump
Bla bla bla

Now for the fun stuff.

Torque, its whats for dinner. It peaked at 564TQ at 5400rpm. But it had 530 from 4600-6650. Hell at 7200 it still had 475TQ!!!!!

HP, its what kills the Chevys. Peak was 670HP 6550rpm. It made 600+ from 5600rpm on up. Still making 650HP at 7200rpm.

BSFC was .395-.459 the entire run and still had a A/F ratio of 11.3-11.9. I wanted to tune more but ran out of dyno time. Valve lash was best at .025I .026E. Ran a 2" tapered spacer fro the Dominator.

So there you have it 670HP with a 396ci SBM and those damn ProComp heads. BTW they are out of stock and will not have any until November.
Click to expand...
How much for a complete set of a similar cylinder heads?
 
The 396 is my engine. Finally got all the piddly stuff I needed to complete finished, and I got my car to the track over the weekend.

1975 Duster ~3500# with me in it. hemi 4 speed Liberty proshifted gears, Dana w/ 4.30 gears, 28 x 9 slicks 12.25#, drag shocks, comp eng slide a links

Sat 15-30 MPH crosswind, not ideal day for testing, no complete passes outta 4, had to lift
Sun calm perfect day, 1st pass quicker than Sat best, made 3 more and got better from there.

Last pass of season finally launched her at a higher RPM after creeping up on it all weekend, appx 5500rpm. (wired two step to line loc, doesn't do me favors for burnout, so I didn't use it gonna add another switch)

Shift light 6800, I believe traps was about 6400.

60' 1.584 330' 4.618 1/8 7.144 mph 97.86 1000' 9.319 1/4 11.158 mph 122.86

She has more in her with a higher RPM launch and a good track plus monkeying with air pressure etc. First time I ever launched a 4 speed at the track where it basically didn't bog, had the deer in the headlights thing going when the shift light came on so quick for 1-2 shift. Perfect shifts/shift points along with 7100-7200 shift light and better 60' time should get me in the 10's. Maybe need 4.56 or 4.88 gears just too early to know, it may be ok with 4.30's? Just ran outta time this weekend with the track being so jammed, and the season is now over.

I've run 15 passes in a 10 second car before, but with an Automatic, old school stick is a real handful but a fun handful at that !! Fun weekend !:burnout:
 
with 9 x 28 tires...I would not go more then 4.56 gears...

you 60 fts are not very good....but the mph shows you should run in the 10.70s....

and with 670 HP....you would expect more mph in the traps....

but ....you went down the track...and nothing broke which is always the good thing...

it takes time to sort out a new combo...
 
I agree 1000% that I got down the track and didn't break anything that right there was a huge win for me. There were a half dozen racers who were not as lucky some parts breakage or not lifting and kissing the wall.

Wished I had taken time out to weigh the car since I'm just somewhat guessing, but it was a zoo at the track, and it would have been a pain. key piece of the puzzle, guess I'll check it in spring, I will be interested to find out.

all advice and input will be noted/and or appreciated, i'm still fairly early in the testing stage 8 passes with 4 of them having to lift due to wind isn't much data. Will still be sorting out things for many passes to come, not too mention making sure I drive(shift) near perfect.

(not sure if I should switch and start a thread elsewhere, perhaps 11 second combo area ????)
 
Well since all the discussion was lost, I'll post the pics of car launching and also at rest.

Please give me your thoughts.
 

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