1931 8-98: cylinder head bolts or studs?

I don't know about later models, but on my '30 8-95 I recently changed the head gasket and they are studs. The 1930's parts list confirms this for models 125, 8-95, and 6-85. For the 8 and 6 it's a combination of long and short. For the 125 it's just long.

Andreas, I was wrong about the length of the headbolts.

I decoded the SZ730 as being 7/16 and 30 1/8's which would be 3 3/4.

In reality the head bolts are 3 inches long measuring from the bottom of the head. The thread lenght is 1 1/4 .

Curt:
The 31-33 bolts are a little bit shorter, two different length: 3-1/8" and 3-3/16"
Possibly the 34-36 bolts could fit. If the thread is long enough, they could be shortened. Do you know the length of the thread?

Thanks
Andreas

I believe the SZ730 (3 3/4) head bolts for 31-33 are the same as 34-36. they would have a W on the head. New ones are available.

Hex head bolts, I got mine from Fastenal in the US. As I remember had to buy a box of 50. Sold the rest to someone a few years ago.

As far as I know the earlier engines were equipped with head bolts, the later ones with studs und nuts.
What is the original design of these screws: cap screws /cap nuts or standard hex nuts/ hex bolts?

Any good source for these bolts or studs/nuts?

Thanks
Andreas