I already have Ported Heads, and just recently picked up 1 7/8 headers, I notice when I put my gaskets up to my head, the 1 7/8 primary is quite a bit bigger than the port. Would it be possible, or worth my time to port match my head to my header, this is a 348 ci nitrous motor, so exhaust flow is very important to me. also the heads are off the car right now so porting them more wouldnt be a big deal.

 

Don't do it. The larger headers actually give you some anti-reversion properties. If you have a choice when you mount them, put as much mismatch at the bottom as you can.