s.
i think the mopar vapor separator is a fairly ingenious part. it filtered and eliminated the vapors, but it's at it's best when matched to the proper fuel pump. the 3-5lb big block pumps were miserable pieces. i remember fighting the vapor lock problem with a 383. it seemed the problem really raised it's ugly head at the track when folks were idling in the staging lanes. i did all kinds of silly things to cure the problem. eventually (sometime in 1968) i switched to a street hemi pump and never noticed any more vapor lock problems (i didn't do a return/vapor separator). but, the high pressure street hemi pump by itself set me up for other problems. all this works the best when parts are matched together..
I fully agree. Most folks don't realize the early MOPAR AFB floats where larger, which means they had a greater buoyance force to keep the needle closed also. That is why they can handle a higher fuel pressure. The AVS used 3 different size floats and had different float setting to account for it. The later Federal/Edelbrock use a smaller float with less bouncy force hence the 5-6 psi limit on Edlebrock.
For a mechanical pump that is a constant displacement, you get faster fuel flow with a higher-pressure pump spring, which also helps keep the fuel in a liquid state in the lines. As long as the float system can handle it, and level set correctly your better off with it.
