Ive got a chevy 250, not exactly sure on the year, because now its in my 82 CJ5. The problem is that I just got through a long and drawn out tranny replacement that took a year to complete due to funds and lack of time. The engine ran good a year ago, but once I got the trans in and tried to fire it up, its been an uphill struggle. So far, Ive replaced : CARB, COIL, PLUGS, WIRES, FULL OF GAS, AND CHECKED TIMING (which I believe is right). We did manage to get it to idle yesterday after the carb replacement, and it would crank on its own. ANY advice will be GREATLY appreciated.

-NIC

You didn't mention if your distributer is HEI or point type or ???..

Dude,
I've done the same swap in my 85 CJ7 and had trouble firing it up also. What I found was the Jeep used a resistor wire going to the coil. I used a HEI ignition on the 250 and this was cutting the voltage down to the HEI.
I just removed the resistor wire and replaced it with normal wire and it started.

Other things I had troube with were I had 2 plug wires swapped around, the fuel pump was bad, and the timing was way off. I think I finally got it running with 4 deg advance but with the HEI I now run about 10 and have the plug gaps at 60.

This was good swap for me. I've ran my CJ every day for about 2 years with this motor.

Hope this helps
Gregg