Here is what the inside of your SPF factory mufflers look like:
SB cars have very restrictive headers...they do not match up well to the exhaust ports on most cylinder heads. Some day I will find $1,000 lying around and spend it on a custom set. I recently saw a used set go through here for $500 (for the AFR heads). If I had AFR heads I would have jumped on them.
For BB cars, the factory 2" ID is a joke (urrgh...I mean,
choke).
-Dean