R5 crankcase

[NSP]

So I need a set of crankcases for my '74 RD350. Found a set on the Bay and paid today.
About an hour ago the seller sent me a message stating "Dear customer, I apologize, after searching high and low for these cases we are unable to find them in our warehouse." He goes on to say that he has an R5 mostly complete engine (also selling on eBay) and he would be willing to break it down and sell me the cases.

Question, is there any advantage to using R5 cases for an RD?

The engine was put back together with all long engine studs so
6 of them are about an inch too long.
I think I already know the answer but I could be missing something.

[m in sc]

r5 cases don't have the 3 bolt bearing retainer for the clutch bearing. does it matter...? not sure. but thats the main difference aside from the lack of crank seal lips. 99.9% sure all the rd stuff will bolt right in though.

[NSP]

That's very helpful since I already bought new seals for the RD cases.
As for the bearing retainer, Yamaha must have thought it was needed for some reason.
Thanks,

[rded]

The 3 bolt retainer added for much better clutch. That 74 RD engine already has the better clutch setup. R5 and early 73 RD350's have the lessor setup. But as mentioned you can use the R5 cases.

I just went through this on an R5.

[RDFL]

https://greenville.craigslist.org/mpo/d/chesnee-yamaha-rd250-rd350-engine-cases/7643773658.html

[m in sc]

those are 75 cases. not a terrible price either.