Hi All,
Well I'm stumped again. I recieved my 1950, 248 cid engine back from the rebuild shop and need to install the three large freese plugs under the head on the intake and exhaust side.
Here is the delema. I ordered a freese plug set from Cars Inc and I can't tell which size to use in this location. They sent three each of two different large sizes 1 62/64 in. and 1 15/16 in. I have searched my original owners manual to no avail. When placing either size in the hole they are to close to decide and I don't wnat to mess this up.
If there is a enyone out here that could help me solve the problem as to which size to use it would be greatly appriciated.
Sgt Mac
P.s. HAPPY EASTER

Use the largest plug that will fit.

You should measure the frost plug bore with a dial caliper. Then measure the frost plugs you have. There should be around .005-.015 press fit in the frost plug holes. If that isn't the case, you need to find ones that are. You can order them by just about any size. ALWAYS put permatex #1 (not silicone) around the frost plug and around the bore before installation.

You should measure the frost plug bore with a dial caliper. Then measure the frost plugs you have. There should be around .005-.015 press fit in the frost plug holes. If that isn't the case, you need to find ones that are. You can order them by just about any size. ALWAYS put permatex #1 (not silicone) around the frost plug and around the bore before installation.
I'm going to guess you're referring to the plugs for newer cars which have a definite wall. Older, 'thin style' (for want of a better term) plugs can't be installed with a press fit. They are a tight slip fit into the opening and are spread by hammer blows to the protruding center; I use an old ballpeen hammer head and another hammer to keep from damaging the plut with a wild swing. But I use permatex also. Be sure to scrape and brush the bore absolutely clean before installing.:wavey:

I installed rubber 1-7/8 inch expanding plugs in my 320. They work just as well and are a lot easier to install. They stand up fine to the pressure, which in cars this old is only about 5 psi. Plus you do not have to worry about damaging the block when you pound in new steel or brass plugs.

I'm going to guess you're referring to the plugs for newer cars which have a definite wall. Older, 'thin style' (for want of a better term) plugs can't be installed with a press fit. They are a tight slip fit into the opening and are spread by hammer blows to the protruding center;

There's really no "old style" or "new style" freeze plugs, as both the cup style and the disc style have been around for a long time. I have a car with the cup-style (1937 Buick) that pre-dates the car I have with the disc-style plugs (1957 Chrysler) by 20 years.

I believe the Buick Straight Eight takes a 1 61/64" freeze plugs