Switched to carb from HSR and I have lost some vacuum for the brakes. The hose from the booster is rubber, hard line and then rubber to the carb. The brakes are sometimes hard and stopping is difficult. Any ideas on a better way to do this? I have a Holley 750 dbl pumper. Thanks.

 

How much vacuum at idle? (More or less than after swap?)

Possible vacuum leak after carb swap?

You might try running hose to a fitting on intake manifold instead of carb.

 

I dont know how much vacuum at idle. I have less than I did before. I will look at trying the intake idea. Does it matter where?

 

Your vacuum line runs from the booster to the carb with no other devices teed off of it?

 

That is correct.

 

Might want to get a vacuum gauge on it first. If you have less vacuum than before, might not be enough to operate booster.

A lot of intakes have threads in one of the rear runners or on the back side of the plenum under the carb to put a fitting in.

 

I will check. thanks...

 

If inadequate vacuum is present at the booster, try a vacuum resevoir.

 

Looked for a port opening on the intake and the only one is in the front. My cam is really big and I have little to no vacuum. I will go with the reservoir. That will work for me.

 

Out of curiosity, how big is your cam? A vacuum pump might be a better idea than a reservoir on a street driven car.

 

I would definitely measure you vacuum at idle first to see how close you are. I have 13" @ idle and have no problems. You might be able to tweak carb mixture and timing at idle to bump vacuum enough to avoid canister or pump.

If you have to, I would also look into a vacuum pump instead of canister. Some of the turd diesel cadillacs in the early 80's had both electric and belt driven ones that should be easy to adapt. Check your local boneyard.

 

I will check on my cam specs. I don't remember what they are. My buddy says that the motor was built to the point where there is almost no vacuum. I am going to try the reservoir. I think it will be adequate. Honestly, I only drive the car 4-5k miles a year. Work is only a little more than a mile from my house. The brakes work, it's just that they are hard at first and then normal and sometimes go back to being hard once in a while. Thanks for the input. I'll let you know how it goes. It should be done somoetime next week.