Changing Hydro-boost brake master cylinder with vacuum boost type?

[mr27t]

Hello everyone,
My wife and I are new to the RV world. We are thinking to go rv living for a while. We just acquired a 1978 M600 32' Executive class A motorhome. It runs good, the interior is in good condition. The problem is the brakes. It has a Hydro-boost power brake booster and master cylinder. I have filled and bled the brakes. The hydro-booster and master cylinder is bad and needs to be replaced. I have searched the internet for the replacement parts and have located a few suppliers.
I would like to change the Hydro-booster master cylinder unit for a vacuum booster master cylinder unit. The Hydro-booster part is #ai527370 and the master cylinder #54-73353.
  O'reilly auto parts has a vacuum booster/master cylinder assembly #50-3122.
My question is this, would the O'reilly #50-3122 vacuum booster/master cylinder be a suitable retrofit for our rv's brake system. I understand that I would need to re-drill the bracket/support for the new brake unit and install a vacuum line from the intake manifold as well as block off or remove the hydraulic lines from the power steering pump.
Any information or input would be greatly appreaciated, Thank you all so much!!!

[khantroll]

May I ask why you'd like to go to a vacuum system? Hydroboost is the modern standard, and I am actively trying to convert my own rig to hydroboost.

That being said, the weight ratings/applications seem similar. The vacuum booster you're asking about is used on the dodge w350.

Do you happen to know your axle rating? The vacuum unit is rated for a maximum axle rating of 4500 pounds, and while that won't be the whole story, it might help dial it in.

[circleD]

Another thing to consider when you change or modify systems. Is the fact of parts availability on the road, a regular mechanic knowing what you did, and most important is to make them stronger than need be if you can.