Technical Sbc rams horn sizes

I have a set of 1970 Corvette rams horns on my 350
I was going to change them for a set of headers I picked up.
When I pulled them off to switch I found the outlet measured 2-1/4 inches not 2 nor 2.5
I could not find any info online and these don't look like they were cleaned up in any way to enlarge the hole.

Anyone ever see some that size before?
The pics I found online either showed 2 inch or 2.5
I can post a pic later

 

Pretty sure 2-1/4 are a standard size, can't say what models they came on..

 

wild guess is that the older ones for 283s were 2" and the later standard ones for 350s were 2.25, and the high perf ones were 2.5. But I'm just guessing. I did yesterday look at a pair of head pipes that were repros for a 69 vette that seem to be 2.25". They kind of fit onto the 2" manifolds I'm playing with, which are off a 283.

if I were more interested, I'd start looking up part numbers....

 

I did look the cast numbers up that's how I know they were for a 1970 Vette
I just thought there were only 2 sizes the 2 inch and the 2.5 but looking at mine they are larger then the early 2 inches...

 

There must be an early and late version of the 2 inch because the info I found online showed the early kind of 2 inch were actually about an 1-7/8 opening
I plan on re installing these I just never saw that size before
Carry on