The OP didn't mention his car installation, only that he had room to fit only one or the other. So...

If installing a cat, it needs to be close to the engien to have enough heat to work. If installing it at the rear, or too far away, wouldn't it eventually clog?


Parts I seek: driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set 16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better. 69-73 C-body caliper brackets and/or splashields Send a PM.