hi guys im running an 89 iroc-z with a 427 big block running aprox 10.5:1 compression ported heads roller rockers edelbrock performer intake and a 750 holley double pumper backed with a world class borg warner t-5 and 3.23 rear end gears as i am planning on going with an edelbrock rpm air gap intake and larger cam something like a lunati voodoo cam and wondering what would i benifit the best from for exhaust and at the moment i have partiot h8012s headers wich are 1and 3/4 inch primary and a shorty (as there are not alot of ground clearance with the hooker swap headers due to the roads where i live) then the exhaust goes in to a 2 and 1/2 inch pipe till you get behind the trans it goes into a 3 inch singal pipe and to a flowmaster 80 series muffler and i like the was the car sounds but i and running in to issues as i cant keep collector gaskets as they keep blowing out does this mean my exhaust does not flow enough ? should i be running dual exhaust and what pipe size ? or should i just build side exit exhaust with th etips exiting in front of the rear tires ? just need good ideas as im really conffused with what should i do and other issue is the car is a daily driver and exhaust cant be way too loud as the police here dont like it lol let me know what you guys would recomend

 

I would run true duals with that setup. Dual 2.5 inch pipes should be fine. If you dont want it overly loud. Run into magnaflows over the rearend and out the back. It will still be loud though. Only option besides that is to double up on mufflers. meaning running multiple mufflers. Its a big block 427 it's going to be loud...that is what it's meant for man!

 

thanks for the great info i agree the car is going to be loud no matter what i do as it is a big block lol but i dont want it to be extremely loud that i cant have a convorsation with the passenger and i am really unsure what mufflers to run as i can get a bullet style muffler with 1 or 2 baffles as you can not see straight through them or borlas thaught of magnaflow and flowmaster but really not sure lol

 

well as long as you go out the back of the car i dont think it'll be too loud to talk. turn down are louder. and flowmasters leavea drone that can get annoying. id go with magnaflow, dynomax ultraflo's, dont have much experienece with borla

 

defimatetly agree about the flow masters as i have an 80 series on the car now lol but is there any point in going 3 inch as i do plan later on maybe building a 496 or possibly bigger and dont wanna have to change exhaust every time i do a change lol

 

dual 3 inch? I dont think its a terrible thing to do that now.

 

ok thanks for the help making my dessision lol now i just have to find the right mufflers lol i will go 3 inch full dual if i can fit it over the rear end lol
i know umi make a panhard bar relocation kit but only issue i have with that is the panhard bar is lowered and i wonder how that would affect the rear end allingment and even more so if i decide to lower the car wich i migh not end up doing due to ground clearence issues

 

and would there be any point in header wraping the pipes where they get close to the fuel tank and the slave cylinder ?