I have a 71 340 block and the oil passages on the right side have been filled/sealed with what looks like braze maybe? I guess it could be epoxy though. Any idea why this would be done? They meticulously filled all the passages between the lifter bore and the galley but the rest of the galley is wide open.
They only did one side.
Any idea why this would be done?

People have odd ways of blocking oil passages when they do other mods, id be shocked at nothing.

Sure its not a brass/copper tube? The common mod way back.

Got pics?

I didn’t take a pic but I can tomorrow. Do you mean a tube like inserted down the length of the oil galley? It doesn’t look like that to me.

The old DC Performance Book recommended sleeving both lifter galleys with aluminum or copper tubes. You then "dented" each lifter bore so the lifter would slide in and drilled out all the intersecting oil passages. This was done to allow roller lifters as the roller lifters of the day uncovered the oil passage at max lift and you lost oil pressure. The procedure and reasoning for it is in the book. This is what is sounds like someone started to do on yours.

Interesting! I’ll have to take a closer look at it tomorrow and see if that’s what they did. The block has been sitting and is pretty dirty so to me it looks like the holes were filled but what you’re explaining sounds plausible. I’ll have to see if it can be undone…

Doing one side seems odd. Most of the time when you see this in one area there has been a repair made. You will be able to see more from the crank side if that's the case.

It was recomended in the DC Racing books to block oil to the lifters when using a roller cam or solid lifter cam . You teamed the gallery on one side and installed a copper tube , and then used a peeling tool that you inserted in each lifter bore, and then hammered it to round the bore back out so lifters would fit . The other side of the block , you installed a plug in the gallery . I did this on all my race 340 engines . If your engine is done this way , you could probably manage to get the tube out , but make sure you get the plugs out of the galleries , and reinstall proper ones in correct locations . Or actually , on that side with the tube , you really only need to open the hole back up at each lifter bore .

I forget the old trick but you could do a few things and just tube the one side.

I cant recall but I ended up with a block with one side tubed and other things plugged, it was a X block from a dirt track car that had a reed cast core roller cam in it to show its age.

I’ll clean it up today if I get time and get a better look at it. Thanks for the help! What year DC book would that article be in?

restricted for oval track use.... ?

I'm not sure the book itself had a date. The individual 'Tune-Up Tips' that make up the book seem to be dated from the late '70's to early '80's. Here is the cover from mine. Yeah, mine is well used.

Great thanks! I think I saw that one on CD on ebay.

Thank you John!

I finally got to clean it up a little and it has definitely been piped and it looks like the #1 oil passage has been tapped just like the article that John posted. I ordered the DC book so I can verify everything is done correctly. So now the next question… undo it or stay the course and finish the job?

Are you running lifters that require the galley to be sleeved? The answer to that question is the converse to your question.

I don’t know what I’m running yet I just have a bare block that I am trying to figure out what’s what

You will need to remove/ reverse to run hydraulic lifters . Otherwise leave it .

I am leaning toward undoing it but I’m going to read the full article when I get it and see if the work appears to have been done correctly and figure it out from there.

If you are going to run solid lifters either roller or flat tappet just leave it there. It helps to keep some oil off the crankshaft and if it spits a lifter out you will still have oil pressure. Otherwise you could remove the plug for the left side galley and drill the tube in the right side lifter bores to get oil to the lifters. Removing those tubes, (there is usually two of them, one inserted from the rear and one from the front) is going to be a real bear. Not sure how you would even get them out except to maybe drill them and that would be a huge pain once they were peened in the lifter bores.