Whilst in Canada over christmas i procured a 450 Holley economaster 4bbl carb with mechanical secondaries, got a rebuild kit, got that put in the carb and am now back here ready to get it put on my 308 to replace the rochester quadrajet. Anyone out there know if it will fit directly on without modification? I'm hoping it will as it appears to have the same bolt pattern as the quaddie and was manufactured to replace the quadrajet on chev's, buick's and pontiac's. Oh by the way, the Canadians were most interested in my commodore workshop manual i took over with me. There are considerable differences between GMH and GM products of similar vintage like firing orders etc. Any advice from anybody having experience with this particular Holley carb would be most appreciated.