Alright, got an LG4 305 1985 Firebird that I just found out needs a new exhaust to pass inspection. This is a good opportunity to get something with better performance so I need advice.

I need a setup that will be interchangable with a 350 from the 305 when I swap it later on. I'm looking to go headers back and yes I'm on a budget. I almost bought a 2.5" setup but I held off because I'm not sure if a 3" is a waste of money or worth it. It's going to be a single cat setup that I don't plan on dumping before the axle.

I'd like something deep, throaty, and loud without the shitty sound when I let off the throttle like I hear on some cars. As far as muffler, I've thought about the Hooker Aerochamber but I'm not sure. Note for the headers, I'll probably keep the A.I.R. tubes.

HELP please!

Oh, if you want to hear my current exhaust here's a link.... http://www.youtube.com/watch?v=hegdVDHNiRw

 

3" pipe with headers is loud and way overkill for a 305. You'll need a 350+ HP 350 to begin justifying a 3" system. Too big a pipe, not enough velocity in the system.

Can't speak to the Aerochamber mufflers other than they look like Flowmasters that I don't like.

 

Man oh man, you're killing my dream! Well, not really because after reading the sticky on backflow I decided go for a 3" exhaust. The backflow sticky includes what looks to be a qualified comment that a 3" exhaust won't kill an LG4. Besides, everyone with an LG4 eventually does somekind of power upgrade, right?

Firebird Mess85, I think you ought to go for it https://www.thirdgen.org/forums/exha...5-16823-a.html

 

This is absolutely false - LG4s pick up a boatload of power when swapping to a 3" exhaust system. Up to 40hp can be gained replacing the y-pipe, cat, and cat back.

And at 325hp (sometimes less), a 3" exhaust starts to become a restriction at the top end.

 

Sounds like a 3" is the concensous? What am I looking for when it comes to headers as far as dimentions as same for the y-pipe? Go for a 3" collector and 3" y-pipe?

 

Hooker 2055's or even Hedmans, same as we recommend for most everyone else.

You definitely want a 3" cat-back for any 305 or 350 engine.

 

a good set of shorty headers with the air tubes, along with a 3 inch catback and a cat converter would set you up pretty good. Don't waste your money with a 2.5, you will see results with a 3 inch and are setup if you ever want to do more modding on your 305 or jump to something a little better.

 

Whats it mean when a header description says "requires head pipe fabrication"?

 

Hey I noticed on jegs it says 86-90 for the 2055's. They should work on 91-92's right?

 

Is there anything to note on the heads that might be different?

 

Head-pipe modification means you'll need to weld it up where the y-pipe meets the i-pipe.

The 2055's come with a single cat y-pipe. Yes it will fit with single cat 91-92's with a little modification, as above. But Tony you want to get Dyno Don's headers and convert to dual cats for more flow.

Small block chevy heads from Gen1 engines (not LT1's and not LS1's) are the same. 99% of headers made for thirdgens will bolt up just fine.