[yossarian19]

1) I didn't / don't know for sure, but the '98 Chevy Astro uses the same part number power steering pump as the 2005 Chevy Silverado with 5.3 - reservoirs may be different, flow valves may be different - but the pump is the same. I was willing to take a gamble and see how it turned out and I won. If you want to be more scientific about it, what you want to do is compare the front / rear caliper piston areas on your setup to various OEM designs and match your MC diameter to one that has a comparable brake package. In my case it worked out pretty close to an Astro van which was convenient, but you want a master cylinder sized to your brake package. Next, you can steal the flow control valve (fitting that screws into the pump, which the high pressure line screws into) from the vehicle you get your booster from & put it in your pump.
Really, though, I tend to just trust the General (General Motors, that is) to keep it simple in their parts inventory and trust that things will work together "well enough" that I can make any changes I feel necessary later on.


I used a firewall brake pedal setup. I used to have a frame mounted setup but found it a royal PITA to work on anything in the vicinity of it under the truck & almost impossible to bleed the brakes. I wound up chopping the end off the hydroboost & threading it 3/8 fine all the way down so I could get the pedal height where I wanted it with the frame mounted kit. I would bolt it all together, see where your pedal height comes out, and adjust things as needed. That applies to vacuum setups, too: you can't expect aftermarket parts to be exactly what you want right from the box. Or at least I haven't been able to so far.

The extent of my playing with the hydraulic system has been to switch to a 13" steering wheel to reduce the leverage & slightly increase steering effort because even with the hydroboost, it felt really light. If you wanted to you could get a set of 3,000 psi gauges & flow meters and go nuts but for the expense and time involved... it's a bit much. Rockauto.com can give you part numbers & lots of information about parts; from there, just rip off as much OEM design work as you can and it'll work just fine.