1988 F-150 4x4. 5.8L(351) automatic.

Which would you recommend and why?

SIDO 5x8x18 Magnaflow or SIDO Flowmaster 40 series?

If I'm replacing the whole system should I use 3" or 2.5" in front of the muffler?

Should I use 2.5" or 2.25" tailpipes.

I'm thinking 2.5" all the way back.

Let me know!

 

Magnaflow because it's got higher flow, straight-through design, and it comes in stainless steel.

3" in front of the muffler, dual 2.25" tailpipes. Why?...because that's what standard pipe tables recommend for your application.