Quote:
Originally Posted by steve25
It does not matter that Tripowers can end up with more CARB cfm then the average Q-jet 4bbl that might be used because there air cleaners as I have proven on my flow bench are a larger restriction, like to the tune of 20% even on the smaller end carbs!
If you compare a 8” diameter x 2.5” air cleaner to a 5” x 4” air cleaner they both have the same area yet the 8 x 2.5 will flow more air once placed on a carb.
It’s impossible for even a 389 no less 421 Tripower motor to hit even just 100% VE with its stock air cleaners.
In fact the 66 set with its 3 large carbs does not make as much power as it should over the 65 set up because of the air cleaner limitations.
The basic rule of thumb for air cleaners is that its diameter should be 4 or 5 times it height when possible.
One advantage that the Tripower set up does have is that once then end carbs open up the tuned length of the intake becomes shorter which raises the rpm of peak hp even though the Tripower set up makes less hp then a 4 bbl factory set up.
So basically the peak hp level of a Tripower noses over slower then the 4 bbl.
And here’s more proof that the added two end carbs on a trip set up don’t do what they should in terms of added more hp.
In one of the 2003 issues of HPP mag they covered a build up of a 421 taken up to 439 cid.
The stock heads were ported up to 218 cfm.
It used a 64 trip set up that was converted to use all 3 big carbs.
This required 3 carb spacers to be made because the spacer used for the center carb was also a adapter to get the needed
bolt pattern to take the big center carb.
The manifold was well port matched.
The cam was a good size solid with .515” lift and the compression was 10.3.
A test on just the center carb made a surprising 350 hp.
Then a test with all 3 carbs in play only produced an added 123 hp and shined a bright light on how inefficient a Tripower intake is!
I get such a chuckle when I see folks who have emptied there wallet to place high flowing aftermarket heads under there eye candy Tripower set up.
It’s such a flat out waste!
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With porting the 66 will flow 340cfm