question on oil pressure relief valve plug

[ryan hollingshead]

i am building a 36hp engine, the case is a 1955. the case was totally stripped of parts when i found it , so i am using some donor parts off of a 1958 case. problem i ran into is the oil pressure relief valve plug on the donor motor is way smaller than the hole on the 55 case . so were there different size plugs or ?? and where might i find 1 if so , i cant find any info. any help would be great thanks

[fcampbell356]

This might help.
111 15 431 Plug M 16 x 1.5
up to Eng. 1 509 952 25-30 bhp

111 115 431A Plug M 14 x 1.5
From Eng 1 509 953 30 bhp
This is a search and find type of item.
Good luck