help! my current exhaust is a joke, 305 manifolds 18" of flex pipe and 2' of 2.25 tubing no muffs. so i just have a few questions before i start to remedy it. i have d port heads and i want to use a set of shorty headers but i cant find any with d ports for a third gen. will it hurt performance to use a larger round or square header? or does someone make a set i couldnt find? the idea of ports not matching up just bothers me. i dont need a y pipe going to dump before axle anyways, might as well run dual. i also need help selecting a pair of mufflers and pipe diameter for my setup(see sig for motor), i want to be able to hear that my cars got ***** when i got my foot down but no drone on the highway, i drove car 500 miles straight with current exhaust, car sounds good... but so loud i barely kept my sanity

 

Can't answer all of your questions, but my 85 had l98 D port heads and I was running O port heddman's. True duals.
As far as mufflers, don't get glass packs. I have stacks on mine, and a pack on each pipe. It sounds like a Harley on steroids

 

https://www.thirdgen.org/forums/exha...-question.html

 

i have Dons headers on my LT1 swap, also D-ports, and they are fantastic. The parts showed up looking great and fit up with no issues. Don custom makes all of his stuff when you order, so if you can wait, they are probably the best bet for you.

 

I have hedmann long-tubes and they are made for D-port heads. I've never seen shorty's but that doesn't meant they don't exist.

I totally understand your want to have D-port headers on your D-port heads.

 

Just cover the port it will be fine