The carbs suck. Badly. The Holley knock off of the Weber 32/36 design they used all warped and eventually had driveability issues. At least they didn't have the fully computer controlled version the non-HO cars received, which were worse.
Replacing it with a proper Weber 32/36 helps quite a bit, plus its a little larger so it tends to improve power a little bit more.
A friend of min campaigns a TBI minivan and has had great luck with it with very few failures. They prepare their drivetrains similarly to above (because preparation makes your money go further as it sucks to have to spend money on entry fees, etc. to just work on your car all weekend), but the lack of a heat and pressure generator allows things to survive much longer.