KZ650 split exhaust collar question

I am reinstalling the aftermarket header that has been on my KZ for years.  Long story short, I discovered that the split collars that I have are two different sizes with two sets at 30mm tall and the other two sets at 33mm tall.  Can anone tell me what the stock KZ650 collar height is?  It appears that the 30mm collars are what I need once the crush of the new copper exhaust gaskets are taken into consideration.

thanks in advance! 

Sorry I do have a B1 but do not want to go and pull one off and measure it,  Will say I have access to several parts list for some of the 650 models and the only one that mentions anything other than part # and name is for the F2,F3 and F4 list that has this info L=14.5   Not sure what that means, but would think some one has some in their parts and could measure them.

Thanks for the post and the information.  I forgot to mention in my post that my model is a B2A.  Also note the the "height" that I noted is the same as length - I called it height because I measured the collar's on my work bench with the flanged part resting on the bench.  According to Kawasaki's web site, the part number for the year and model that I have is 92027-264 and there is no length given.  I called the local Kawasaki dealership to check stock but they didn't have one although they are still showing that part number as still being valid and available to order.  I read through some forum archives and see several instances of there being mention made of "long" and "short" collar's but no dimensions given.  If all else fails I'll use a band saw and cut the four 33mm pieces down to 30mm.

Is this not determined by the thickness of the flange (you wouldn't want them sticking through)

The F2/F3/F4 exhaust collars are probably the same as the KZ650-CSR & they're shorter than the earlier collars, because the models noted have flanges welded to the header tips.  The earlier 650s have flared header tips, so the collars are longer.  The exhaust pipe collars for your 650 appear to be available at Partzilla & probably the Kaw dealer. Part #92027-264. Partzilla is showing pics which usually indicates a part is still available.

I don't offhand know the length of a stock collar on B/C/D models, but I do know that the F series exhaust has a very short collar. I have a F2 exhaust on my one bike and was surprised at how short these parts were, they work fine if you have the F flanges as they are also "Unique". 15 mm sounds about right for those.

I happen to have my '78 650 B2 exhaust off my bike. When I get home from work tonight I'll measure the collar for you.

Perfect! Thank you! Is your exhaust stock or aftermarket?

The collar is 1.18 inches long. The exhaust is stock.

Thanks OKC Kent!  1.18in. = 29.97mm so 30mm it is!  If anyone needs 33mm collars I've got four....Thanks to all that helped!