i have a near stock lo3 atm.

i am curious, will headers with 1 5/8" and 3" exit enough to support this engine once i have done my mods to it (intake manifold /camshaft / heads) or should i go 1 3/4" ?


my plan is real simple.

i want headers with 3" exit into a 3" y pipe which goes to my electric cutout valve. and i can have that open when i race.

this way, i dont have to worry about spending the money on a catback system.

and with the mods listed above, would it even be possible to follow the dual cat system and run true duels with 2 cutouts on each pipe before the cat?

if uneed to know exactly which parts i am using for my mods i can tell you.

 

It has to be a mighty healthy 305 to need more than 1-5/8" primaries and 3" exhaust. Chevy High Performance magazine dyno'd a 355 for their "My Generation Camaro" at 380 HP with such headers. I doubt you're going to need more.

Otherwise, you're talking about custom exhaust with the cutout or cutouts. A single 3" should be more than adequate, but you could do the duals. Since it's custom, we can't tell you exactly what parts to get, although a search on "cutout" "cut out", or "cut-out" should yield the info to get you going.