M1, Victor340, and RPM Air Gap flow testing

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pittsburghracer

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Ok so I don’t trash up the M1 post I had going and to save confusion let’s start a fresh post stacking these three intakes up against each other. This test was on a ported Edelbrock head with 2.055 valves.



——-Head—M1 intake—-Vic340
.100—64——————62—68
.200—125—————125–131
.300—187—————183–192
.350—214—————213–218
.400—238—————236–237
.450—257—————246–251
.500—284—————255–259
.550—294—————256–260
.600—296—————258–262
.650—302—————271–272
.700—308—————279–280
 
Now let’s add the RPM Air Gap to this and this because again I’ve never used this intake I’m taking it is different than the RPM Performer?





-Head—M1 intake—-Vic340–RPM
.100—64——————62—68–66
.200—125—————125–131–131
.300—187—————183–192–188
.350—214—————213–218–211
.400—238—————236–237–227
.450—257—————246–251–241
.500—284—————255–259–250
.550—294—————256–260–254
.600—296—————258–262–251
.650—302—————271–272–254
.700—308—————279–280–250


As you can see the RPM Air Gap totally trashed a good flowing head causing it to get noisy, turbulent, then backing up. A dual plane was never made to work on a head flowing 308 but it shows you the importance of not just grabbing an intake off a flea market table and throwing it on your engine combo. Both of these heads the Victor340 will be tested again after some porting but will be tested hopefully on a different head. Hopefully have this pair of heads finished this week and gone.
 
Question!

Are both flow numbers of the intakes OOTB stock?
 
I’m taking that’s the regular Victor 340 and not the Super Victor? Just curious at this point what intake it takes to keep up with that much cylinder head.
 
Now let’s add the RPM Air Gap to this and this because again I’ve never used this intake I’m taking it is different than the RPM Performer?





-Head—M1 intake—-Vic340–RPM
.100—64——————62—68–66
.200—125—————125–131–131
.300—187—————183–192–188
.350—214—————213–218–211
.400—238—————236–237–227
.450—257—————246–251–241
.500—284—————255–259–250
.550—294—————256–260–254
.600—296—————258–262–251
.650—302—————271–272–254
.700—308—————279–280–250


As you can see the RPM Air Gap totally trashed a good flowing head causing it to get noisy, turbulent, then backing up. A dual plane was never made to work on a head flowing 308 but it shows you the importance of not just grabbing an intake off a flea market table and throwing it on your engine combo. Both of these heads the Victor340 will be tested again after some porting but will be tested hopefully on a different head. Hopefully have this pair of heads finished this week and gone.
I think the rpm intake flow shows why most 400+ ci sb strokers struggle to make over 500 horsepower with the rpm. Its just too small.
 
I’m taking that’s the regular Victor 340 and not the Super Victor? Just curious at this point what intake it takes to keep up with that much cylinder head.


Yes regular Victor340. It will take a ported Victor340, ported Super Victor, or a ported and modified to fit Indy intake.
 
Im curious what the rpm air gap numbers would be with the divider milled down like they do on the small block chevys
 
I am very surprised to see how little diff there is from the stock victor v/s the air gap all the way up to 600 lift.
 
So at what point do you make the call to go from the air gap to a single plane for a mostly street driven engine?

Lets say eddy heads/or eq heads that flow about 260 @.600 are on the hypothetical engine. 340 or 360 engine.
 
But the Air Gap got turbulent before that. Very jumpy numbers on my digital flowbench then numbers that backed up. Not good. Not good at all.
Probably a much wider spread from best to worst port with the edlebrock as well I would assume.
 
I would say if it’s any kind of stroker at all, you’re already past that point… I’ve know of at least one member with a hot stock stroke 340 that have went faster going to an MP single plane from an air gap, with the time slips to back it up.
 
Probably a much wider spread from best to worst port with the edlebrock as well I would assume.

A dual plane intake reminds me of a dirt track figure 8 race I went to as a child. Everything and everyone was going in all types of crazy directions.
 
I updated that post mentioning one person in particular with a 340 that went faster with a single plane to an air gap. 11:1+ with 4.30s and a four speed in a Duster.
Yeah racing no doubt which one. I was just thinking at what point is the juice worth the squeeze to make the switch on a street car that doesn't see the track often.

Also no doubt if one pays the money to have heads ported one should go with the single plane and have PBR work it over.

Guess it largely depends on what someone calls a street daily driver cam. Lets say duration of 230@ .050 and .550 lift. Wild *** guess- run the one you have as there may not be enough difference to change.

Of course if you have to buy one, then buy the one that allows for the inevitable tweek the engine for more horsepower creep.
 
Yeah racing no doubt which one. I was just thinking at what point is the juice worth the squeeze to make the switch on a street car that doesn't see the track often.

Also no doubt if one pays the money to have heads ported one should go with the single plane and have PBR work it over.

Guess it largely depends on what someone calls a street daily driver cam. Lets say duration of 230@ .050 and .550 lift. Wild *** guess- run the one you have as there may not be enough difference to change.

Of course if you have to buy one, then buy the one that allows for the inevitable tweek the engine for more horsepower creep.


My next set of Speedmaster heads will be interesting. I haven’t done a full port job on a set of heads with a stock 2.02 valve in a long time. Being the throat is already at its max from the factory I will be limited to setting my own angles by hand instead of using my seat cutter. That would probably be a perfect fit for this ported RPM intake especially on the street.
 
wounder how a holley strip domanator would do compared to your victor and M1???


I’m not sure. Or the Port A Sonic 360 I ran back in the 1970’s. I do know I tested an old Torquer I ported for my son and they suck. But it did test better than a ported Speedmaster dual plan.
 
I would say if it’s any kind of stroker at all, you’re already past that point… I’ve know of at least one member with a hot stock stroke 340 that have went faster going to an MP single plane from an air gap, with the time slips to back it up.
when i was 20 i bought a pumpkin off a 45 yr old guy in early 80s
He had bought a brand new 69 notch cuda s 340 727 3.23s he bracket raced it for 20 years. He told me he tried every setup they had cams carbs intake gears
He settled on stock cam advanced tm5 single plane 700dp 3.55s 50 series street tires they were wider then my L-60-14s factory manifolds and exhaust spring clamps
His dial in was 13.1 it ran 13.1@104 he had quite a few Trophies
He had a stroke 7 or 8 years later at a grudge night caught up with him the car hadnt been run for awhile he said the carb was acting up it bogged of the line blowing black smoke out the tips still ran 13.3@101 mph i laughed and shook my head.
stock 340
intake carb 3.55s low 13s
10 trophies or more in his basement
 
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