You have 28 oz vs 50 oz. Be careful of the years of each engine too. The bellhousing will also possibly be different and thus a different number of teeth. Ford does us all a disservice with the multiple flexplates they use. Try finding a 50 oz flexplate with 157 teeth to mate to a 1968 Mustang C4 trans..... Grrr.
The only thing that is the same 4.9L/5.0L/5.8L is the 164T M/T flywheel ring gear (C5AZ-6384-D).
Now that I think about it, the flywheels are different. I did a 4.9 to 5.0 swap once, years ago. However I believe I used the 4.9 pressure plate and clutch. And I do believe I got another flywheel for the 5.0.
OK this is good help, My 5.8L flywheel is marked E8TR-BA don't think this is the part number of it is it? No, it's an ID engineering number, not a Ford part number. Marked w/ID number: E8TR-6375-BA = Ford part number E8TZ-6375-C
I called Ford today and they said the flywheel is discontinued?? Considering that the last MSRP was a horrid $457.77 (dealer net cost was bad enough @ $274.66), I doubt you woulda bought one if it was still available.
Should i just get one from napa? And What should i get? A 1994 F150 5.0L manual flywheel? or should i get a 1994 F250 5.0L manual flywheel? Did you see what I typed in post #6? It's the same tamale. 1988/96 F150/250 & Bronco 5.0L: E8TZ-6375-D
351W flywheel is not the same as a 5.0L The 5.0L flywheel is not the same as a 4.9L
Alvin in AZ (retired RR 'signal ape' and a well known raconteur on Ford truck websites) gave you a ref for rockauto.