1949 Chevy 3600 into a daily driver

[Coach529]

Originally Posted by 99 to Life

congrats on all the work. The vacuum shouldn't haven much to do with the spongy feeling pedal, all that does is make it easy to press down. I'd bleeeeed the brakes over and over. Also the prop valve needs to be for correct setup and sometimes the bore in those MC make a big difference. I'd also think once you get a harder pedal, your engine should pull more than 10-12 vacuum. I'd play with timing and idle and honestly if you have an edelbrock, put the vac advance on the drivers side FULL ported vacuum. The Pass side is partial port and was more of a smog era deal, so you prolly aren't getting enough timing to pull good vacuum. Sounds strange but the more it revs at low RPM the vacuum will move up until a certain point, say 20hg and then it drops back to zero. Just try the vac advance and I bet you will notice a difference.

I have great pedal feel with the truck not running. Once the truck is started the pedal seems to go soft, spongy. I order a vacuum canister and a reverse bleeding tool. They will be here tomorrow and I will try and address the issue.

Vac advance is set up on the FULL ported vacuum on the carb.