[fratt77CJ7]

Still having probs w/muffler. Whenever I patch or replace mine I get some backfiring. Bad enough to blow out the patch or bust the muffler. I've given a complete tune-up, reconditioned a head with a bad seat. New intake, exhaust, and head gaskets. Can't figure it out. Does not happen as long as there is a whole in the muffler (no back pressure I guess). It runs fine otherwise, starts right up, no ping/knock. Any ideas? Thanks all.
fratt
"77 304V8, TH400 auto, Qtrac

fratt

 

[CJDave]

/wwwthreads_images/icons/crazy.gif Just a crazy thought, but I suspect that what is happening is that enough air is getting into the system up front that it is allowing for combustion in the header and muffler. By chance is this a 304 with the air pump? And if so, is the diverter valve working? /wwwthreads_images/icons/tongue.gif

CJDave

 

[fratt77CJ7]

Thanks for the info. I'll check tonight. Not sure if it has an air pump. The Jeep is a '77 but not sure if this is the original 304.

fratt