G'Day Mick,
Come along to next weeks meeting and ask a few of the guys who have done this conversion. The "little additional cost" you mention is not all that little though.
Even by using second hand parts you would be looking at LEAST a few thousand dollars - HR disc brake front ends are around but the last one I saw fully rebuilt cost over $1000.00 in parts, add rear brake changes, the engine and box (not allowing for any reco-ing), changes to the floor pan, replacing the rear brakes, and an engineers including any body rust repairs and I'd reckon you'll EASILY spend a few grand or more.
Now those Jack Myers headers on eBay, a nice cam and some head work, multiple carbies, and a 3.55 or 3.36 diff replacement will set you back less than half of that and won't need engineering or any body mods.
Anyone else got any thoughts?
Cheers,
Craig.