I am 90% sure it's 5/8" too. I had to replace one of my T's a while back. None of the parts places had them, but I did find them at Home Depot / Lowe's back in the plumbing stuff.
Well, it must have known that I was on here telling on it.
Got up this morning and headed to work. I turned the cruise switch on and set the cruise.... it worked perfectly all day, just like new.
No rhyme or reason...
http://www.ebay.com/itm/6-2L-6-5L-GM-Diesel-Injector-Return-Line-Kit-6-2-6-5-/280812562387?hash=item4161bba7d3&item=280812562387&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr
had really good luck with this line during my build. No clamps to fool with.
So, back before my head gasket blew a couple months ago, my cruise worked just fine. Then the head gasket blew and I replaced the engine. After the engine swap, the cruise didn't work at all. It stayed that way, not working at all, for about 45 days or so of everyday driving until yesterday...
I found this tractor on craigslist, in North Vernon, IN. A friend and I brought this home on Feb 2, 2012. It's an Oliver 70, and looks to be a 1946. It needs some minor mechanical work here and there, but does run and move :).
Looks great. I see the whole 8 piece set on ebay for 62 bucks with free shipping.
http://www.ebay.com/itm/New-8-Piece-Set-Headlight-Signal-Marker-Lights-SAE-DOT-Chevrolet-Pickup-Truck-/330680722302?hash=item4cfe1b637e&item=330680722302&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr
In almost all cases, it's better to use a 195 thermostat. A lot of people have said they lose MPG when they switch to a 180 thermostat.
Just FYI before you buy/replace it with a 180.
X2 on what has already been said.
That exhaust and coolant tank is exactly what mine did/looked like when I blew my headgasket a month ago. Mine had 252,000 on it and the heads were cracked between all the valves. Just FYI for what you will probably run into with yours.
The oil fill puffing...
Hopefully you can measure the length and size of a 6.5 rod bolt and see what they have. It's gotta be close to some common engine rod bolt, big block chevy, ford..... something.