I am fitting the headers to a 51 3100 with a 235.
The instructions say grinding is necessary as it has always been. That seems like an poor excuse but I did it. What really bothers me is the wall thickness varies from just over 1/16" to just over 1/4". (wall thickness, not the flange thickness). $300 should buy a better quality casting than that. Is there a better manufacturer out there or is this the norm?
