I installed my headers this weekend, and are they ever loud! When driving the T/A, when I come off the gas, I have a lot of backfire. I realise I'm hearing a lot more engine noise from the headers, since my exhaust and muffler have so many holes in them (next paycheque), but should I be backfiring this much? I just set the timing and replaced the plus 2 months ago, but should they be redone because of the headers? Any ideas would be appreciated.

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1988 Pontiac Firebird
1986 Pontiac Trans Am

 

A lack of backpressure is what causes the gurbling sound. Fix the exhaust and this will help.

If you are hearing loud explosions (like Uncle Buck) then you are leaking gas into the exhaust.

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1986 Trans Am
carbed 350 - .30 over with 9.75:1 comp.
+- 315hp/390ft lbs.
700-R4 with 2500 stall
3.27 (ick!) gear
SLP 1 3/4" headers w/MAC catback and cat.
96 5 stars
SFC's, braces, arms, and a bunch more expensive stuff
no timeslips yet

 

No loud explosions, just pops and snaps and the usual. No big "uncle buck" explosions.

Anybody able to recommend a good 3" cat-back system? My catalytic converter disappeared mysteriously while installing my headers, and the exhaust has many, many holes in it.

 

I know this may sound stupid but are you sure you got the firing order right? This will cause the same problem so just check to be on the safe side.
Other than that your headers will have caused a lean condition in the engine. If the car is fuel injected the O2 sensor should have picked it up it is just carborated you will need to up the jetting. (Check your spark plugs to be sure on the lean/rich condition.)

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84 Z28 383
Stripped w/Cage back halved w/ladder bars and coil overs and 9 inch
700R-4 3.73

 

The firing order is correct.

It's carb'ed so I'll have to play with the carb and adjust the jets I guess.