Street Demon Insulator

Demon designed that carb to mount on any square-bore flange (not Dominator of course) which is why the secondaries are actually one big valve; they couldn't make the opening in the throttle plate any wider so they removed material between the two sides.

So yes any 4150 or Edelbrock square-bore insulator, spacer, gasket etc. will fit fine. I know on my 750 Street Demon the manual says to make sure to use the included metal plate under the carb at the very least (with a gasket on both sides) so that the atomization for idle and transfer slots works correctly. For mine I have the carb, then paper gasket, thin plate, another gasket, 1/2" wood fiber spacer from Edelbrock iirc, then one more paper gasket on top of an Edelbrock RPM intake.