Can't be said better. Sounds like a suspension rebuild along with a brake up grade are things that should be first on the list.
When I found my 63,after a good tune up of the bone stock 170 Slant six,next was brakes and suspension rebuild.I went with the 73 up A body large bolt pattern front discs and a 1974 A body big bolt rear axle with the 10''x2 1/2'' brakes.
I may have missed it but is this a budget build ? It would help us all if we knew if it is or not.
When talking about QA1 and other items that is not what I would call budget, we can lead you into the right direction and better help you.
By the way I'm a big fan of the Slant Six but that is your call.
Please tell us more,long term or short term plans. This sounds like fun.
