Your hard starting problem is probably political in nature, rather than mechanical:

http://www.thecarburetorshop.com/Troubleshooting.htm#Hardstartcold

If the mechanical pump is producing too much pressure, (opinion) the better avenue would be to (if the pump is original) rebuild the pump with the CORRECT internal parts (a plug here for "Then & Now Automotive" in the Boston area). If the pump is incorrect, then acquiring the correct pump.

If you should use a regulator, DO NOT go the your FLAPS and buy one of the $34.95 inline regulators, regardless of what brand is on the box. Find a good speed shop (or a FLAPS that sells Holley regulators) and get one of the expensive Holley regulators.

Disclaimer: I do not own stock in either Holley or Then & Now.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop