2 Strokes Down Under

Do all the RZ 350 barrels have 31k stamped on them on the reed block? The reason I ask is I was looking at an RZ 250 top end and it had different markings not 29k.
And if so is there any difference between them. I have an 83 RZ 350 with a 250 top end that I am about to convert back.
Cheers

What are the markings?

31k barrels 83,84 model 350, 29L 250

However both cranks have 29L stamped on them.

1ua later rz barrels however not as good porting as the 31k.

Thats what I needed to know, thanks Antman

Also later models have powerjet carbs,31k carbs are very similar to Lc these are good carbs.