V-12, new build, tough start, fuel volume, timing?

[atomman]

OK, got the v-12 new build firing, however, I am using a stock fuel pump. By going to two 600 Holleys, is it even possible for the mechanical fuel pump to provided adequate fuel volume? Also, as I read the book, the timing is straight forward, however, getting some back fire with the initial start then quits. Any insight is greatly appreciated :deadhorse:
Atomman.

[bigblockv6]

Are you running 2 Holley 600 4bbl carbs on the V12? I would think the stock fuel pump that supplies two little WW2 carbs that produce around 280cfm would be no match for two 600 Holley's:ahhhh:

[TJ's GMC]

I think a carter electric pump is needed. One I have is a 100 GPH that supplies 4.5 to 8 psi and has 1/2 brass ports. Yes, 1/2 inch! lol Sucker puts out some Volume!

[Jim A]

I have calculated my fuel usage several times over the 45 years I have owned my 1960 3/4 ton 305 A with the stock 1bbl Holley. It has worked out to 10 MPG at 50 MPH on the highway or 10 MPH in the woods.
I don't know much about V12's but I sure hope they do better than 5 MPG.
But even at that milage, 50 MPH would be 10 gallons per hour, surely within the performance of a stock mechanical fuel pump.
That 100 GPH would empty the fuel tank in about 10 minutes.

[bobdylan]

I am running a electric fuel pump on my v12, The first fire up is tricky, I had fire all the way to the garage ceiling. You made sure your rotors were pointed at l and r, timing the number one side by turning distributor, and timing number 2 side by turning points plate?