Just had a brand new pump gas 383 With AFR 195,s and Hyd Roller setup ,, AED 750 DP and all dialed in on a dyno.
Running a 2500 stall TH/350 and 3.44 eaton tru trac.

The headers are 1 3/4 hand made and the car did have a single 3 inch system thats going to be replaced.

Are these cars running a single 4 inch system or duel 2 1/2 inch,
my frame has been setup to run a duel system if i want.

 

Not sure exactly what you're asking but there are systems available from single 3" to 4" and dual 2 1/2". If there's a dual 3" available i can't say.
Now if you're asking what's best for your 383, I'd say put all the exhaust that'll fit. The muffler is the cork. Get a big single (which is going to be loud) or two mufflers like the Hooker BlackHeart.

 

Hello Mate
thanks for the reply

I am in Australia and my car of 25 years is right hand drive and i was running a 408sbc with L31 vortecs and hand made 1 3/4 headers and a single 3 inch y pipe into a single 3 inch system,,1 x cat,, 1 x 3inch straight through glass pack muffler and a 3 inch rear straight through short muffler,
car sounded like a big block and ran flat 13.0 @ 107mph all night for 4 years.

I bought a new 383 From Klein Racing Engines in Phoenix Az and its about to go in and i dont talk HP numbers as its just talk.

I was mainly asking whats the most common setup to run mainly from performance side of things. As this new motor breathes a lot more air in and i need to upgrade the old system.

Over large pipes can lose power and there is some math needed to get it right to get the power we are looking for.

As for the sound its not my priority the get up and go is.

I really need 1 7/8 headers to match the exhaust ports but i got my old 1 3/4 headers and they were expensive enough as its right hand drive and another set would cost too much.
Left Hand Drive headers wont go on this car.
Its ALL custom unfortunately.

 

Going through my notes, I've come across some tech that suggests exhaust port CFM can be useful in determining the primary diameter based on the application. 1 3/4" looks acceptable in a street/strip application with ports moving 210 CFM at full lift. That would be in AFR 195 territory. If you can dig up the head specs maybe that'll help you dial that in.
A general rule is 2.2 CFM of exhaust system capacity per crankshaft HP is required before output starts to be limited to due lack of flow. Trying to get as much exhaust in there as you can will be your best bet. Don't get caught up in the "over large pipes" thing. If output is the main concern, and that 383 isn't some monster making 600 HP then your 1 3/4" headers (inside diameter) into a pair of mufflers (exiting under the car) will offer the least restriction and allow for the most output. At 500 HP, you're looking for a pair of mufflers that flow 550 each. A 40 series Flowmaster is capable of that. Among many others.
Now if this is an all out race engine, where your most of your time is spent at or very near peak RPM, then that 1 3/4" may be limiting.

 

Thanks again and good information i thank you again. We often see cars here with duel 3 inch systems on stock LS engines in locally built cars and while the local exhaust shop is quite happy to take your money and build a system that is overkill and really expensive for no reason.

This motor is no monster and when i spoke to the engine guy in Az the combo he used constantly run around 500hp and he said a few have run 530hp and we left it at that.
When i had the 400 in the car and the th350 i had the headers made and we had to cut the frame on the American drivers side in the area close to where the fender bolts on and brace it up so the 3 inch Y pipe could link up to the headers and i could run a duel system if needed as is.
The 1 3/4 headers have 3 inch outlets and i just hope the exhaust shop can get a duel system up under the floor.

car will be driven on the street and only see 6000rpm at the strip.

Keep in touch
thanks again .