Adding ported vacuum

[Zac Agee]

OK recently got cliffs book and want to add ported vacuum to my baseplate the main body is done drilled from flat spot on drivers side to the intersecting passage that meets with the opening in baseplate for the ported location. Is slotting the baseplate like factory did better then just drilling a hole? If drilling a hole works fine how big should it be? And if drilling hole instead of slotting it should the bottom of the hole be were the stock horizontal slot should be? I have another baseplate and carb with ported source to get measurements from but the carb and baseplates isn't worth fixing/ swapping parts so id like to add it to the carb i have kit from cliff for and already in process of building. I have the ability to slot it but i don't see why a hole would be any different
Any help with this would be excellent!

zac

[Cliff Ruggles]

A hole is fine, provided the lower edge of the hole is in the correct location.  I would drill it to apprx .050-.055"......Cliff

[Zac Agee]

Thanks Cliff. So should i put the lower edge of the hole at the location of the stock horizontal cut? That way it comes in just above idle like the factory? Factory ones seem to be almost at the top of the transfer slot so bottom of the hole i drill will be there. let me know if that sounds right...   

thanks

[Cliff Ruggles]

Yes, the bottom edge of the hole must be precisely located to provide ported vacuum right off idle, but zero vacuum at idle speed, just like the factory did......Cliff