Different style 350 heads?

[1976RD400C]

I'm trying to figure out what's what. I've noticed most RD350 heads look like the one on the right, but I have one marked 350 that is different. The inside fin is wavy and not cut down as much. Anyone know something about that? Thanks

[teazer]

I believe that the 350 head is the 1/2" reach plug with interrupted fins.  I am sure that the other head with wavy fins is a 400 head, but M in SC will know for sure.

[m in sc]

the 'split fin' head is r5/ early 73 rd350, they changed to the single fin for 350's 100% 74/75. UK models of the 75 (b) are slightly different and i *think* have 3/4" reach plugs.

[1976RD400C]

That makes sense, thank you. If anyone needs one of these (old or new style) $40 + shipping from NY.

[RustyRD]

Chuck Q. Team Scream had told me that the wavy head was more resistant to warpage, better choice than what he called the shark fin head (earlier version)

[m in sc]

ive heard that as well. Ive had no issue running them on stock-ish motors though. (whats on the r5 w rd cyls and fpp chambers)

[350GUY]

Them wavy heads are less prone to cracking and have greater beam strength for clamping the gasket uniformly....