I've got mr gasket comapany headers on my car with a 262/270 cam and crush bent 2inch dual exhaust. I want to upgrade my exhaust but I am unsure of what to do. I think my options are 1. Get a Borla and have a custom y pipe bent. 2 custom y pipe and a single 2.5 pipe to single in dual out 3. same but with 3 inch pipe. 4 Custom y pipe 2.5 pipe halfway then enlarge to 3 with single in dual out muffler. I have no cats so the Borla will also need a custom y pipe. The best option I think is the single 2.5 pipe. I am worried about overscavenging the cylinders with a cam with that exhaust duration and a big pipe (2.5or3in). Could that even be a problem! Thanks

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82 z28 350cid, vortec heads, comp 262h cam, Holley 600cfm carb, 2in twice pipes, MSD ignition, turbo 350 trans, 3.73 posi

 

Get a Y-pipe with 2.5" inlets and a 3" outlet (Jegs and Summit sell them). Get a 3" pipe to the muffler. Don't restrict the exhaust too much like what you've been explaining. I'd say get a slightly larger carb also.