Can we talk about 350 ci power

[WorkinLonghorn]

Hi. I recently got a "rebuilt" 350 for my '69 GMC 2500 and,to make a long story short,I ended up getting a much lower compression ratio than intended.( I'm guessing 7.5-8.0-1). I recovered my money (plus some) but I am not too happy with the "power" produced by this dog.
Let me say that I am a pretty cheap SOB and so I will not be installing a blown 454.I'm just looking for some tips for getting more power.
A) Will switching to HEI actually make a difference? I realize that the entire timing curve will have to be re-adjusted due to the lowered CR.I put an adjustable vac advance on but it seems that there is not enough centrifial advance.
B)Would it be advisable to have the heads and Intake mani milled to increase CR or is it better to just change the pistons?
C)What about jets? It is a bone stock quadrajet. Any suggestions on upgrades for carb?
This is a heavy truck (about 5100 lbs.with tools) and it will do alright as a work truck,but there's more to life than work. -thanks-cougar
'69 GMC Custom Camper Longhorn 435CR 4spd,350 4brl,373 Dana (open),stock wheels,stock distrib.