JBA Shorty Primary Diameter
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From: Citrus Heights, CA
JBA Shorty Primary Diameter Just got my JBA shorties today. When comparing the primaries to the stock exhaust, it looks like the JBA's have a smaller diameter. Are all the gains in the collector? I'm putting on ported heads and ? using a header with smaller diameter primaries than stock. Anybody else notice this? 
I was thinking of cleaning up the opening of the primaries slightly. Has anyone done this? I don't want to cause a leak.
I was thinking of cleaning up the opening of the primaries slightly. Has anyone done this? I don't want to cause a leak. Last edited by Redneck Z; Jul 12, 2005 at 05:04 PM.
Ya, ya should've went with the hooker shorties, or some long tubes. You'll probably loose more horsepower from those constricting JBA's than you'll gain from the heads. You should probably just give up! 
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I'm only looking for constructive comments....don't you have anything better to do? 
I spoke with JBA about this and they said they are they same way on the corvette. They said torque peaks 200 rpm sooner and they flow better up top with the better tube and collector design. I think I'll clean up the primaries a little, just to make me feel better.
I spoke with JBA about this and they said they are they same way on the corvette. They said torque peaks 200 rpm sooner and they flow better up top with the better tube and collector design. I think I'll clean up the primaries a little, just to make me feel better.
