I took Old Red out for a test drive this morning before work. Here's what I'm having trouble with:
1. The engine heats up fast and gets much hotter than it did before the rebuild. I've got 20W50 oil in it and the right mixture of antifreeze. The whole cooling system is new including the radiator.
2. The transmission will not shift into high gear (it's a 727). The fluid level is correct, all the connections are in place and low-speed works ok but it won't shift up.
3. The engine is very sluggish. It's acting as if it's not getting enough fuel when I step on the gas. I have to wait for the engine to cool down to check it out but I'm thinking one of the two injectors isn't operating right. I'll check that out and get more info back on here.
Any ideas anyone? Is there anything I might be overlooking?

 

Air pockets in the back of the block could be a reason why it is running hot, so is too much timing and running too lean of a mixture.

 

Year, make and model of engine? Mods?

Why are you using 20-50? What is bearing clearance?
Injectors? What year and did you make any other mods (cam?) or just stock rebuild?

x2 on the air and timing. Especially if cap isnt high point on system..

 

Was the trans working before the rebuild ? Start with the basics. check timing, 10W / 40 would be a better choice for oil. How many miles on the rebuild ? Being a new engine IT may run warmer until it breaks in a little.. It should not get hot. Possible ? bad thermostat

 

It's a 1989 Dodge 318 engine, no mods other than being bored out .030 when it was remanufactured. The comapny that did the work recommended 15W-40 oil but that was a little hard to come by so I went with the 20W-50.
Right now the throttle body is my primary suspect. I'm starting to think that an injector either is clogged or just not operating, which would make the engine burn lean and that in turn would explain some of the overheating problem and the lack of power. All the electrical and vacuum lines are correctly installed but I'm not certain if I've got a wiring issue or not. Looks like I'll be spending some quality time with a multimeter this weekend. What else should I be looking for? (Fuel filter is new and good gas is in the tank.)