2863216 vs 2863215 cooling fan-diffferences???

Hey ya'll, so here's the deal:

I have a factory 71 22" 3-row 340 radiator with 71' shroud for my 360 stroker build in my 70 duster. My issue is this, for this car the 2863215 fan is factory (all 68-72 340's and 68-72 318's with a/c) got this fan but I have laying around a 2863216 fan (all 73+ 340's and 318's with a/c)

The only difference in the two is the pitch:
2863215=2.25" pitch
2863216=2.5" pitch

Which fan will cool better in my application? Will i have clearance issues using the 216 fan with the 71 shroud/radiator? Thanks in advance, -Dan