Originally Posted by pracy
I am thinking, prime the carb by injecting fuel, take coil lead off and crank motor til bowls are full?
...let me preface by saying that I don't have any BG carb experience.
You shouldn't need to crank the engine to fill the bowls. Just dribble a bit of fuel into each vent tube and then splash a dab down the primaries and fire it up. Sometimes it takes a couple of splashes before the engine has turned enough to completely fill the fuel bowls, but it will turn much more rapidly than cranking on the starter!
What I usually do on a fresh engine with no electric fuel pump (fairly rare these days) is to fill the bowls through the float sight plugs using a fuel-resistive squirt bottle. I manually move the accelerator until jets of fuel come out of the squirters (accelerator pump circuits). Then I give a short squirt from the bottle and crank it up. A couple of quick pumps of the pedal are usually enough to get things going so that you don't have to get out and do it again. When you think about a mechanical fuel pump that can deliver only 2 GPM, in 10 seconds it is going to move ~43 ounces of fuel in those 10 seconds. It won't take very long to fill your float bowls.
One of the things that I do on my Holley carbs before installing them is to preset my float levels. I'm guessing that the same can be done for a BG carb, too. Also, be sure to use a good quality fuel pressure regulator set to a starting point maximum of about 4.5-5 psi. Adjust upwards if required.