I have a set of 915 B/RB heads that I was going to use on a budget build. One of them has 1/8" pipe plugs in both corners on the exhaust side (see pic, sorry about focus). Does anyone know why this was done or what they are for? I have a stack of B/RB heads and have never seen this before. Thanks. -Mike

Other pic.

Somebody's idea for air bleeds maybe for complete coolant fill????

joe

Are they into water jacket?

I think they do go into the water. I'm kinda afraid to take them out because they look like they've been in there for 40 yrs; probably have.

it may be done to remove all of the casting sand from the inside passages in the head.

could be for removing air when filling coolant so it does not get steam pockets waiting for t-stat to open and burp the air out.

could be for an indust engine with a temp sender or water take off for heating up carb choke/intake.

could be for oil cooler return or supply maybe.

but,knowing what passage it taps into such as water/oil/exhaust would help.

my 77 452 heads with peanut plugs from a motorhome,has a pug on one end of the front driver side head,but smaller than those in your pics.

the spare 452 set I bought has the machined area but no plug on either of them, I cant seem to find the reason it is there either.

what yr are the 915 heads?

..if they go into the water jacket, it looks like a good place for a pair of these at the back of an engine.

I believe all of the 915 B/RB heads are 1967.

I would be afraid to take them out. Grind them flat and paint if they bug you. I have not seen them either but my B/RB knowledge is slim.

I have one 346 head that has those pipe plugs, and have seen it on a 452 head at a swap meet before too.

I've never been able to figure out why, but it almost appears to be either a factory test or repair of
some kind

Never had an issue with the 346 head, used it for many years

Interesting. Nothing like that on my 915s.

You may want to just ignore them, because some pipe plugs are not solid.
They look lke 1/8" pipe plugs, if you really want thm out, heat them up pretty hot and as they are cooling, apply paraffin to the outside. As the casting cools, it draws the paraffin in and makes it easier to get the plug out. Of course, then you have to have something else to fill in the hole!
R.