Does anyone have an exhaust dump in their system? Did it help at all? Does it leak? What is your setup?

My exhaust consists of 1 5/8" headers, 2 1/2" catback with no cat, and crossflow flowmaster 3-chamber muffler. Would my setup benefit if I installed a dump in the y-pipe where it is still 3", that way the system would go no smaller than 3" in diameter? I figure I'll have about 350hp after the cam install and a few other mods I have planned, if that helps answer my question at all. Thanks.

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1986 CAMARO Z28 -> 151,000 original miles, 43,000 on 89' vette 350 block, Holley 650 DP, Weiand intake, 1.6 rockers, 1 5/8" headers, no cat, 2 1/2" Flowmaster catback, Mallory coil, March pulleys, T5 with 3.35 1st gear and 0 miles, 90% Centerforce clutch, 3.73 posi, Eibach 1" drop springs, Spohn LCA's, Spohn adjustable panhard rod, Subframes connectors, polyurethane swaybar bushings/endlinks, 2 12" Sound Streams, 2 Infinity 6X9's, 2 Pioneer 6X9's, 800 watt Lanzar Vibe amp. ET 13.22@ 106.4MPH 3300lbs less driver and speakers Next mods-> Homemade ram air, B&M shifter, Extreme Energy 230/236 cam.

 

I was thinking about doing the same thing, after the motor swap. I e-mailed hedmann's tech dept. and the # 68470 headers bolt up to their y- pipe (2 1/2"), and they said it can be modified to include their cut-outs.

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1987 Trans Am
"Tired, old 305"
4 barrel, 2.73 rear
700R4 + B&M stage 2 Transpack
1980 350 Small Block sitting on the stand waitin' for heads.....

Best 1/4 mile time:
16.075 @ 85.52 MPH