Backfire issues

[VileZambonie]

Check the firing order and make sure you didn't cross #5 and #7

[greenkeeper]

I changed the plugs and wires when I installed the new carb.  The plugs were so bad that I think two of them weren't even firing anymore since the electrodes were worn down to nothing and another one was fouled pretty  bad.  The truck also had a small exhaust leak at the manifold in one of the emmission air tubes.  I plugged that up and thats when the problems started Go figure.  I'll recheck to make sure #5 abd #7 are not crossed.  After that im not sure what to check.

[DnStClr]

Could it be that by plugging the leak it allows the fuel-rich exhaust gases to enter into the hot exhaust pipe , where combustion takes place (backfire).

[greenkeeper]

Ok, so I called a local supplier for a new muffler for the truck and the list on it was $365.   I asked him if it was made out of  gold or platinum. He tried to match up a universal but no luck.
Where can I find a cheap muffler for my 88 R-30 350 dump truck? 

[choptop]

Any muffler shop worth going to can put in a replacement muffler. To find an exact replacement, maybe not, but one that will fit, if they cant do it, leave. They are incompetent.