minor chassis swap "left over" issues - help

[68GMCCustom]

I swapped my '68 GMC's body onto a '72 C10 chassis I had. This was so that I can do a complete build on the '68's chassis while still using the truck, and enjoying the upgrades the new chassis offered over the old one. The swap went well except for a few minor problems....which I could use the help (and expertise) from the folks around here to resolve.

One is the throttle linkage. I upgraded from the '68's rod type to the '72(or maybe 86?) cable linkage I had, using Putter's thread as a guide. Unfortunately I lost the pedal side end of the cable and had to fabricate a temp. solution. Where do I get one of those plastic cable ends that retains the cable end at the pedal? Also, due to where I cut the hole in the firewall and the fact that the towers (6 cyl?) have the SBC mounted in the farthest back possible position (barely room for the dist.)...the cable's too long. Is the 4x4 throttle cable shorter then the 4x2 cable? And if so, what is the overall length of the cable (or difference)?
My fan shroud is also too short. If my towers are in the rear mounting holes on the frame, is that the production 4x4 SBC mounting location? So I would need a 4x4 fan shroud?

Also, I have a leaking master cylinder (rusty/cover) that doesn't seem to work as well now, as when the '72 was parked for the swap. I kept the system closed during the swap but without a cab, the poorly supported m/c slightly bent the lines and the m/c was at about a 30* tilt, but after remounting the line's look OK. I've checked out the entire brake system (and bled the fronts) but don't seem to be getting much braking from the discs. I'd rather not upgrade to power brakes (for cosmetic reason's) unless I have to...and wondered if I were to replace my master cylinder ('72 C10 non-power disc/drum) with reasonable performance in mind...what would it be? A 60's Corvette style m/c? Or aftermarket? I'm trying to keep the cost down on everything that relates to the '72 chassis (which is what my trucks body is on) so I can put my money in the '68 LSX/chassis build...but don't want to sacrifice saftey with what I'm going to be driving until its finished either.

Thanks!