The 750 is 1 3/8
The 800 and 850 are both 1 1/2.
The 850 are all Competition Series Cars with a
different Primary boosters than the production 800 carbs
as i recall.
The 1000 are 1 1/2 but with a different booster set up.
This is from memory as I am Out of State Consulting this week.
I will look thru my 100 plus Thermoquads for your # when I get Home next week.