difference in heads both from RD 350

[Still biking]

can any one explain the difference?

[Czakky]

Left looks like my R5 heads

[SUPERTUNE]

Not much...they're both blown up!
Take a pic of the inside side.
Are they sharkfin or wavy heads?
Chuck

[Jspooner]

I have never seen an RD350 head that looks like the one on the right.

[Still biking]

The one on the right came from a stock, 1975 RD350 engine, that, by looking at the OEM, std size pistons, it would be reasonable to assume the head was never off the engine.  But it does not at all resemble either the R5 or the RD350 head I have seen before.  Seems to have less porting for heat dissipation.  Why??????

[Still biking]

And the fins are almost identical to other stock RD heads.

[m in sc]

weird. no '350' casting either.

is it a radjoot head possibly? (indian rd)

[Still biking]

No this bike was a california registered bike that I restored.  And a 1975.  Engine was not touched.  Not a Radjoot. 

[m in sc]

IVE NEVER, EVER SEEN THAT. I'll look in my stash of heads see if i have anything similar.

[teazer]

Since it is a very late production head, it may have been a design change that preceded the wider fins on 76 on 400s and 250s.

[Still biking]

What is the difference between the R5 head and the RD350?  Are they interchangeable?

[m in sc]

only as pairs, there are differences, chuck knows them off the top of his head, and i think year matters as well for cc and shape

[Still biking]

I was concerned that an R5 head on a RD350 would change compression ratio.  The two bikes have different spec compression ratios.

[m in sc]

like said, has a different chamber volume. i think its within 2-3 cc's, chuck will chime in im sure. either way, stock heads should be recut these days anyways, and r5 heads aren't too strong, the later single wave heads are better for use. 

[Jspooner]

can any one explain the difference?

I think the one on the right might be a TR3 head.