My 70 GMC pickup (350/350) has drum brakes and a manual brakes & I want to change to power brakes.

The question is this, is there a different master cylinder for power brakes than there is for manual brakes for the 70 drum/drum combo.

In looking in the LMC catalog, there is only one master cylinder for 67-70.

In 71 it changes to a different one depending if you have manual or power brakes. Is that only because in 71 they had a disc/drum brake combo?


Next is the issue of running the vacuum line to the power brake booster.

I do not have a port at the back of the carb to hook the vacuum line to. I do have a fitting in the manifold that runs to the modulator for the turbo 350.

Would it be ok to put a double line fitting in the manifold and run the trans modulator and the brake booster at the same time? Is this even possible as the vacuum lines are different sizes?

Would it just be best to put in a carb spacer with the brake booster line in it?

Thanks in advance,