Thread: Hushpower II flow cfm?

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I have been reading all the articles and forum posts I can find about muffler performance testing for cfm and for sound. I have found a good bit of info...very helpful. Although I have heard several positive comments about the Flowmaster Hushpower II mufflers as far as the sound goes, I have not found a bit of testing results for the muffler in bench cfm flow or real world dyno comparisons between this and other performance mufflers.
I would like to keep flow loss to a minimum with an AMC 390, ported 291c heads , 1 5/8 headers, Air gap intake, 750 vacuum holley, 268H cam with 1.7 rockers, and I'll be using 2 1/2" pipes full length. I have a stroker 401(433 or 454) in the works that will be a 5500 rpm max motor with a big torque curve. Basically 500ft lbs of stump pulling for a convertible with 3.15 gears and a super t-10 with a 2.88 first gear. Both the mellow old school tone and the space restraints I have trying to keep everything tucked up cleanly have me interested in the Hushpower IIs. Any kind of standard case muffler body will be dificult to fit, even short body 14" can turbo mufflers. I am definitely NOT interested in a 500 decible exhaust that sounds like a raging animal. I have a solid lifter 12.5:1 sbc 383 69 Firebird that takes care of the attitude end my personality just fine. I want a relatively powerful cruiser that sounds mellow and as quiet as I can get away with without choking the power potential.
If the 2.5" Hushpower IIs flow as well(or close) as the dynomax hemi turbo or ultraflows I'd be thrilled to say the least!! Has anyone tested them!

George

Don't know. But with a high torque long stroke engine, once you have good headers and big exhaust, the difference in horsepower from one quality muffler to another would be very negligibile..... Dang near down to which one trips your trigger.... Doubt there would be 3 hp difference on a chassis dyno between the two.......

I wouldn't be suprised. But few seem to be using them. Wouldn't it just be better for all of us if muffler manufacturers just published the flow numbers that we all know they have already have in their posession. I'll give Dynomax credit for doing it. Will they always be alone?

Anyone else know of any hard data on the Hushpower IIs? I'm a numbers guy!

George

Last year I asked the rep from Flowmaster what the HP rating of the Hushpower muffler was, and it was only good for 400 Ponies! Basically 200 a bank (side). I was seriously thinking about them too. Not now... Good luck.

Keith...

Thanks, that helps for sure. If the Flowmaster guys say they won't flow good enough for my needs...not much point in looking further. I quess I'll have to do some mild rearranging down there to fit some good standard case type mufflers.

George