In the mean time don't destroy your engine with LOM venturi vacuum advancing the HEI vacuum unit.
Disconnect the vacuum line and plug it if there is a spark valve on your Autolite 1100.
Vintage Inlines has an carb adapter to install a later larger 1 barrel carb.
1V Carb Adapter (Large 1V to Small Log) SKU: FSP-200-1VA-LS $75.00
The original air cleaner where it mounts to the carb inlet can be enlarged if need be.
This billet adaptor is use to install a Carter 1V carb, with a 1.75" carb bore, on a early model cylinder head with a 1.5" carb bore. The adaptor comes with a 3/16" phenolic spacer and two gaskets (stock manifold gasket not included). Carb studs are extra. No machining required.
www.vintageinlines.com