I am in the process of changing the power brake booster on my 87 D150 to the smaller 3/4 booster. I have the aluminum m/c, but the booster for the cast iron m/c is cheaper and more readily available. Can I use that booster with my aluminum m/c? What is the difference? Thanks in advance. Matt

Doesnt the cast MC use 4 mounting bolts/studs where the alom MC uses 2 bolts/studs??

They both use two bolt mounting

Shouldn't be an issue that I can think of

They are two different part numbers, so I was wondering if there is a difference in the plungers.

I doubt they made 3 different rod lengths. I've only heard on power and manual rods

You may find that the bolt spacing is different for the cast iron booster.

IIRC the cast is going to be spread farther apart than the aluminum.

A little FYI on the booster. I had to drill out the mounting holes on the aluminum m/c to 3/8s. The rod between the m/c and the booster is also approximately 1/4 longer than the original. I made a spacer out of 1/4 inch aluminum and everything works great. Noe I have valve cover clearance. Matt

Did you install a 440 into the truck?

If you have could you maybe post a picture of the PCV valve area.

I'm trying to figure out why mine won't fit with the small booster and factory valve covers.

It fits. Jamie arent yours