Dale Davies
Well-Known Member
Semis running on the chassis dyno would drop 25 to 30 HP when the fan cut in. Big fans though.
AIR GAP INTAKE WORTH THE MONEY?
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Deltatech
Well-Known Member
Ya, a heavy load on an alternator can reduce a lot more power than people realize.
dartindanno
Well-Known Member
Is it worth swapping a Victor 340 for an Edelbrock RPM air gap?
dartindanno
Well-Known Member
I don’t know any of the specs on the 340. Haven’t done a compression test and it has stamped rockers.
It’s all combination dependent. Form the years, I have noted that on average, the heavy street strip type builds or bracket racers that the dual plane/single plane split is about, give or take, [email protected] on the camshaft. While this is only one part of many, it is the biggest single factor besides cylinder head flow (for power abilities) that decide where the rpm of an engine will perform.
The average time slip is at the slowest I have seen at 11.00 & slightly slower. Several members have tried and tested a single plane vs a dual plane at this and slower speeds in which the dual plane had the advantage. While the engine/car combo did slow down on the top end, the lower end in getting off the line was a big factor. Also consider weight a lot as well. As a heavier car will favor the dual plane vs the lighter car which can afford to loose some lower end torque and still take off very fast and then dominate the top end brutally.
On your engine picture, seeing stamped steel rockers is normally what I’d say is a bad sign for performance. It could have been a lack of funds to not upgrade to a better rocker.
The big key here for you is to know what is inside the engine. The only other option is to test a RPM yourself and see what difference it makes to the seat of the pants for the driving you do most or the intentions of the car. If it is the strip that concerns you the most, then a few tests are needed to try a side by side comparison of the two intakes.
If the track is something you travel a lot, then you should have plenty of data to compare against when the RPM is tried out.
Single plane intakes were designed for ether sustained high rpm usage, like high speed or rpm driving around a track or as in drag racing, the high end charge which pretty much requires a big camshaft. But what is a big camshaft? Pretty much if you’re racing and making use of a single plane intake well, that’s a big camshaft. In my opinion, the smallest camshaft to use with a single plane is at [email protected]. And make that at a minimum a SFT!
Though a lighter car that can RPM very high and take advantage of sustained high RPM can get away with a smaller camshaft.
Also a dyno may show big gains with a single plane over a dual plane even with cams as small as [email protected], is this really what will work on the street in an average weight street car or even one slightly lightened? I’ll tell you outright the answer is NO!
I know there are other fellas lining up their fingers to the key board right now to call that size cam, [email protected] (and myself) whimpy and small. That’s OK. But that’s what I have noted over the decades.
This is your sig;
“70 Dart with a 1973 340, iron heads, 727 with reverse manual and 3500 stall 4:56 gears”
What does the Dart weigh and what are the scales telling you on where the weight is? Front and rear, left to right?
The year of the block is useless information pretty much.
What is the exact displacement? (B&S) And compression?
The stated iron heads is another useless bit of information.
What’s the casting number or letter? What size valves? Ported? How much? Flow sheets? Back cut valves? What kind of valves? What size stems?
The 727 & 4.56 gears are very cool to read. The stall converter rating however, @ 3500, is very very low for a race ride but about average for a nice street strip car. That of which does t mean a single plane is good or bad.
All of this and more is needed to actually make a good suggestion in which intake would be best or preferred for the cars intent and your driving needs.
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This post made me think a little. The last hydraulic cam I ran was in 1977 and it was a 509 purple shaft with a four speed. I never ran a dual plane intake.
Everything is a series of compromises. Depends on wants/needs/whims/etc..
To me this where cars generally fall
Race car, almost zero drivability compromises.
Street legal Race car, can it survive a 15 min trip around town.
Street Strip, racing still primary function but can handle general street driving without much concern.
Street Machine, Max acceleration still has a great importance but you could jump in the drive long distance without too much worry.
Hot Street, where streetability is max concern with decent performance.
Street, zero to very little care for performance.
Obviously you could do things like take a stock /6 car and use it only on the track and call it a race only car etc..
AND? LOL!
Well, it certainly has enough duration to operate in single plane territory. I’ve ran that cam in a 10-1 -365 cid with the LD-340 & a big TQ, Torker II 340 w/a AFB, & the AG-RPM and a AFB.
The dual planes were a big improvement over the single plane in the street. Faster overall. Once I moved away from the 2.02/1.60 J heads to a set of RPM heads, the improvement was even better.
I have that 292/.509 on the shelf today.
Well, it certainly has enough duration to operate in single plane territory. I’ve ran that cam in a 10-1 -365 cid with the LD-340 & a big TQ, Torker II 340 w/a AFB, & the AG-RPM and a AFB.
The dual planes were a big improvement over the single plane in the street. Faster overall. Once I moved away from the 2.02/1.60 J heads to a set of RPM heads, the improvement was even better.
I have that 292/.509 on the shelf today.
I don’t care who likes UT or not. But I love the saying on this mug.
Dale Davies
Well-Known Member
Those fans are not electric, they are air applied.
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