BOTH Mechanical and Electric fuel pumps
 

In my 1970 Monte Carlo I had a mechanical fuel pump. It would run fine once warmed up, and never gave problems then. Then only problem it did give was the fact that it would take about 20+ minutes of starting, trying to hold the gas down so it wouldnt die, and sometimes it just wouldnt start at all.. I decided to switch to an electric fuel pump, so I took the mechanical one out and replaced it. The car would start up after a few trys, but then if I were to put it in gear it would die... If I let the car sit for about 7 minutes and then put it in gear, it was warmed up adn ready to go. Now both of these problems were irritating me, so I put both in at once. WOW, best of both worlds! It starts up with 1 turn key, and I can put it in gear in 2 seconds and it will drive. Of course I dont need to leave that quick though.. lol.. Anyways, I was reading that it may cause problems having both run at once. Is that true? If so, can I put a regulator on the fuel line so only a certain psi goes through? Or a LAST possible choice, a switch to turn the electric on/off for when starting the car till it warms up? Thanks!