The one that perplexes me the most is a fuel problem. The car is a 64 Polara with a fresh 440(420 H/P-510ft/lbs)It has an electric fuel pump which is not usually hooked up and a mech pump.After priming the carb it fires up but won't stay running.Acts like it runs out of gas and no gas pumping into carb. Activated the electric pump and motor runs fine. I figured the mech pump was shot and replaced it with a new one.We primed the carb using the electric pump and fired it up. It will run for about 2 minutes then runs out of fuel and dies. I'm just gonna run the electric pump,but am curious as to why it will run 2-3 minutes on the mech pump.I didn't run it for more than a few seconds with the electric cause I wasn't sure if it was safe to do so useing the mech pump too.I read the electrc/mech fuel pump post so I am a little more informed in that area now. Anyway, any ideas on why it will run 2-3 minutes then die?

May need to check the fuel pump push rod.

Can you bypass the electric pump?
Just to see if the mechanical pump works by it self.

Deleted prior to arrival of politically biased moderators

Hookup a can of gas w a neoprene line to the (mech)pump inlet & fire it up. This will cut the problem(area) in half & tell you if the issue is w the mech pump(& pushrod if BB) or rearward(elec pump/tank pickup/hoses.

I had a similar broblem when I put my 68 together this spring. Then brand new mechanical fuel pump I bought wouldnt pump. I finally pulled the pump off to replace with another and found that my engine guy had somehow missed the push rod with the pump rod. I put a length of hose on the pump after I got it off and dropped it into a bottle of gas. If i worked the arm by hand the pump shot gas from the outlet port. Put the same pump back on and its been fine ever since.

Thanks to all for the imput. I'll start troubleshooting tomorrow and see what I find.