I'm new to using forums, but I am in desperate need of some help and am hoping someone here can give me some insight.

I have a 1971 K/5 Blazer with 350 matched to the TH350 auto. I inherited it from my Dad. He converted the points ignition to an electronic ignition system. It currently has a Mallory Unilite distributor and and MSD Blaster coil.

I ran this Blazer for about a year with no problems. Last fall it started leaking tranny fluid which quickly went from a small leak to a major leak. The pan bolts were slightly loose so I went ahead and did a fluid, filter, and gasket change. After completion I started the Blazer up...it was running for about 5 minutes when it kind of sputtered (much like if it ran out of gas) and died. I haven't had it running since.

Over the course of the last 6 weeks or so I started getting back into it to try to get it going again. The tranny leak wasn't fixed and the engine still wouldn't start, so I decided to start with the tranny first. I pulled it thinking it was the front seal, but found the pump bolts half way out. Needless to say, I found the cause of the leak. Since I had it off anyways, I went ahead and replaced the front shaft seal and the seal around the pump housing. I reinstalled the tranny and went to work trying to get the engine fired.

First I found the coil was getting just slightly more than 6 volts, so I ran a new hot wire to it from the fuse panel. it is slightly under 12 volts now. After doing that and messing with the timing by rotating the distributor, I have managed to get the engine to start. The problem I am having now is it starts right up and runs smooth for about 5 seconds, then dies almost like you were turning the key to "off."

The fuel pump was replaced a few months before the Blazer quit running last year...when replacing the fuel filter I ran the pump for about 3 seconds and it filled my container, so it seems to work great. Over the last few weeks I have replaced the starter, fuel filter, rebuilt the carb, and put in new plugs. I have not replaced the distributor or the control module inside. Does anyone have any ideas or suggestions? Any other information I should give? Thank you sooo much!!!

And by the way...I only have basic automotive mechanical experience and knowledge. Beyond typical tune up stuff, everything I have worked on with this Blazer has been a new, learning experience...

Mallory Unilite distributor (old)
MSD Blaster Coil (new last fall)
Carter AFB Competition Series Carberator (old; rebuilt yesterday)
Belden Premium wires (new last fall)
NAPA Fuel pump (new last fall)

 

*Moved to 'Full Size K5 Tech'*

 

You need fuel, air, & spark in the right quantities and the right timing for the engine to do it's thing. Have you confirmed that you are getting a nice blue spark at the plugs? What did you set the primary adjustment screws at when you rebuilt the carb? A baseline that I have used for over 20 years is fully seat the mixture adjustment screws and back them out 1.5 turns.