Im sure this has been asked before. But i cant seem to find a thread tgat adequately answers my questiin. I have a 84 z28 with a lg4 im doing a full gasket job and just installed a new cam. Im wondering if i would see a bigger gain w. Shorty headers 15/8 to 3the inch collector and air tubes. Or a catback exhaust. Im on a tight bugdet so the headers would have to be fit to the modified stock y pipe. They come with all the hardware. Thats $250. . A dynomax catback is 220a and a 75$fresh mail in rebate. Will i see any gain from either of these mods with my lg4 and new cam. Whats the most bang for my buck. Sorry my typing is crap im on a touch screen cell ohone. Lol

 

Btw im a little worried about the dynomax catback only being 2.5 inch diameter. Most people upgrade to 3the inch. Stock my car is 2.25. But ive read a certain amount of backpressure is good for power and/or torque. Perhaps most camaro aftermarket exhaust are 2.5 because of the torque loss that may result from bolting a full 3 inch exbaust onto a little 305 or perhaps the backpressure has more to do with tube diameter and collectors then anytbing. Does anyone ever consider this when upgrading exhaust.

 

The factory manifolds and y pipe on these cars suck very bad lol. Best bet would be to put headers on with a good y pipe or just do a good 3in cat back for now then do headers later on.

 

idealy both is the right answer . but that me your on a tight buget . i put the headers on first . then ordered the obx 3" cat back exhaust a month or two later . i feel like the headers first will give you the best gain . because they get the exhast out of the heads quicker . what cam did you put in ? an just fyi headers an 3" catback an a tune on an otherwise stock l03 i'm up 50-60 hp ...i still have a lt1 cam an aluminum intake to add but i need more fuel first . i'm out at 3725 rpm .

 

Its edelbrocks 305 smog cam 194s to 214 @.50 duration and 420 440 lift or something like thatm

 

This is a tuff call. I do know a good set of headers will run you some $. I would go with a nice catback for now. Headers are nice but they are hard to fit to a stock Y pipe.

 

If you live in CA. (some county are exempt from smog testing) than you have to be careful changing anything that the visual inspection wont pass. If you do need to test go to the station of your chose (before hand) and flat out ask them exactly what will pass. The visual smog test I get here requires me to put back on the stock air filter assembly and set my timing back to stock “0”. By the way its from the manifolds back to the cat that they don't like you touching. I managed to get my cat grandfathered in.
I decided to skip the headers for that very reason. I run a high flow Magnaflow cat with a 3in. Flowmaster American Thunder exhaust. Car runs great and sounds great.

 

I live in california =pThere is a set of carb approved flowtech headers that will fit my car from summit. Flowtechs should be on sale right now. The original price is 250a it has all the hardware to modify your stock ypipe for placement. I will eventually need the matching ypipe which costs 150 and a cali cat which may run 60 to 100. Pricy. I think ill get all this done first and eventually learn to weld so i can make my own catback with glasspacks. What do u guys think?