427 center oiler question

[rritchey]

There is a 427 block on e-bay it says it is a 69 block. The auction number is 4533369214. Here is my question.... there is a picture in the auction that shows the back of the block - I can see the side oiler bosses in the lower left that are not drilled... so I know it is not a side oiler. However, in the same picture, you can see the rear of the block up at the cam plug.... and there is not a hole there for a center oiler pressure relief plunger. Anyway, I've never seen a 427 block that did not have a pressure relief plunger in one of those 2 places, and this block clearly does not have one. Any ideas? I thought it might be a 390 or 406 block that someone added cross bolted caps to (some early 390 blocks had the bosses in the block but did not come with cross bolts installed, same with some 406 blocks) but the date code is definately 69 which rules that out.

link to auction

[Excaliber]

Don't know about the pressure relief butt...

I thought ONLY the 427's had the screw in freeze plugs. It could be one of the "side oiler" service blocks that were never drilled to be side oilers. I've heard some people drill the oil passages out and then it "becomes" a "side oiler" after that.

Are you saying that some 390 or 406 blocks DID have screw in feeze plugs?

[rritchey]

Excaliber,

I know it is not that big a deal to tap the freeze plug holes and put in threaded plugs. It is also relatively easy to tap and thread a 390 or 406 block to accept the cross bolted caps (so long as the block has the bosses). I've done both of those procedures to blocks for customers who requested it (so their blocks would look like a 427). I just don't know of any 427 blocks that did not have a pressure relief valve in the rear of the block either at the rear cam plug (center oiler) or in the lower left hand corner (side oiler).

[Excaliber]

Wow, thats something I hadn't thought of, machining in screw in caps! A friend was recently concerned that the Cobra he bought might have a 390 (seller said 427 side oiler, "rumor" has it might be a 390). I didn't have a lot of time but checked for the screw in freeze plugs and they were there! Based on that I said it's most likely a 427, will have to check further to see if it's side oiler.

Now I'm worried it really COULD be a 390 "converted"! The motor also had the cross bolts, but now I guess I can't rely on that either!

[FFR428]

Excal..early 427's had the press in freeze plugs.
RR..the 406 and 390HP both had the oil pressure releif valve also. It's possible it's a marine block your looking at. It should have brass screw in freeze plugs. They are cast as sideoilers but machined for centeroiling. Have a link for the auction???

[Seaman]

I have seen a 427 block without the pressure relief, a guy I work with had it about a year ago. I sold him a set of DOVE cross bolt caps for it. Definitely an ex marine block. Good luck.

Dave

[rritchey]

FFR428,

The link to the auction is in my first post. After a little more research, I have found out that some later marine blocks did not have the pressure relief. It must be a marine block - but it is not a "cast as S.O. but drilled as C.O." block because there is no center oiler plunger hole at all. I'm not so sure it is worth having anyway, because it has a crack that must be repaired - definately a roll of the dice.

[SCOBRAC]

Looks like an industrial (reject) engine or a marine engine (slightly better than reject).