I don't quite understand your comment about needing a short distributor. Do you mean that the cap should physically have less height, or are you thinking about a "small cap" distributor which resembles the old style points distributors but has approximately the same height as a conventional HEI cap.
I run an Allstar cap in my Nova. Conventional HEI also fits but I know this gives me a bit more clearance (about another 1/2")
Allstar Performance - racing and high performance car parts, accessories and specialty tools.
Here are alternative links to distributors:
CHEVROLET Distributors - V8 Engine Type - Mechanical Advance Type - No Mechanical Tach Drive - No Marine Use - SummitRacing.com
Crane Pro-Curve Billet Distributors 1000-1501 - SummitRacing.com
Chevy Pro-Billet Small Diameter V8 Distributor - 8570
Hope this helps.