Thanks for the info on the rings. I will give them a call and post what I find out. Thanks again for the help and all the good advice.

OLD MAGNET, you ask "what procedure did the welder use? I got my block back Friday. He used gas with brass rod and then peened it when he was through welding. He also drilled and taped a 1/8 pipe plug for a "drain plug" on the "aft" side about a inch from the bottom and told me to use a copper plug so it would not "rust up". I have to get a set of telescoping gauges so I can mic the inside diameter of my cylinders so I can call "Hastings Manufacturing" and order my rings for the pistons. I'll let you know how that works out. Thanks again for the help.

I got my inside mic set Friday. Mic' d my pony motor: #1 cyl outboard side horz was 2.752, vert was 2.753, center horz was 2.751 center vert was 2.751 inboard end horz was 2.751 vert was 2.749 ( no more than .004 dif) #2 cyl at outboard end horz 2.749, vert was 2.753, center horz was 2.756 vert was 2.758, inboard end horz was 2.752 vert was 2.752 (.009 diff) I called "Hasting Manufacturing" at 269-945-2491 and spoke to a lady named Dawn at ext:1359 ( very knowledgeable lady)(didn't laugh when I told her I was working on a 1937 RD4 caterpillar pony motor). She ask me to measure the piston grooves and see if they where 1/8, 1/8, 3/16 and 3/16. Which they where. She said I needed a "7700" ring set, she had them in stock and would cost me $33.05 plus $7.50 shipping.

#1 cyl looks pretty good only .004 diff. #2 looks border line with .009 diff. Does anyone know if this is okay or do I need to have the #2 bored?

Service manual states:
Cylinder bore wear limit (out of round) at 0.004
Cylinder bore wear limit (taper) at 0.006
Piston clearance (skirt) 0.004 - 0.006

The one cylinder is pretty good but the usual procedure is to bore them both even if only one is out of spec.

New rings will not seat in a cylinder that is out of round.

Thanks Old Magnet for the help.