58 Pontiac M/C - Power Booster Upgrade Question

[Vagrant]

...I was in the garage today taking some measurements for the upcoming M/C - Booster switch and considering the limited space I have in that corner I think I need to ask you all for some opinions / advise at this point...

The original booster (w/ single m/c) was only 5" in diameter, so I was figuring I'd go with a 7",since I have some clearance issues...Well most of the brake companies around (MP BRAKES , CPP etc) seem to think the 7" booster will not be enough...They're recommending 9" , 8" at the very minimum to stop my 4,000 pound Pontiac. The thing is, I
don't see how I'm going to get 9" in this confined area and
they aren't giving me many ideas to work on....(they suggested I mount the unit under the floorboard but I'm really not looking to do that. )
I MIGHT be able to squeeze in an 8" booster....maybe.

Any suggestions?

[Duck]

I think the engine compartment in the Pontiacs are very similar to the Chevys. That being said, I have a MPB 9" Corvette Booster/Master in my '58 Chevy. When it first arrived, I said the same thing, "This is never going to fit". The booster would have hit the valve cover.

So we had to space it up a few inches with some homemade brackets and spacers. The geometry is still OK after moving it up, and the brakes work fine.

I can get some pics if you're interested.

-Duck

[Pist-n-Broke]

Ask yourself this, If the stock 5" worked for all these years how much better is the 7" going to be? Also, is the new 7" a dual or single diaphram style? Are you also going to disc brakes at this time? Any improvement will be better than it was and it's been working for 40 plus years as is.
The Wizzard

[Vagrant]

Duck

Thanks for the info...yes if you get a chance, Pics would certainly help

[Vagrant]

Pist-n-Broke

The new M/C would be a dual diaphram. I'm planning on staying with the drum brakes for now.

[Duck]

OK, got the pics right before it started raining.

This one is looking from the passengers side. The bottom mount for the booster is now on the top set of the old master mounting studs. It moves the whole assembly up almost 2". I think we used 1/16" steel to make a big plate that mounts to the lower studs, and that the top mounts for the booster mount to. Of course there is a large hole in the center for the rod to go through. We also used two pieces of ~1" wide steel bar on either side (again, I think 1/16") to reinforce the mounting points to avoid flexing when hitting the pedal.

This is just one pic, the others I sent over email. Let me know if you have any more questions.

-Duck