273 Commando Engine Build

MonkeyTrev said
Thank you for the great information regarding the engine build! I know the factory intake is a single plane, but I only plan on street driving the car and a dual plane would add better low end torque. I had not even thought of the air cleaner base plate and I appreciate the info. Do you have a link to the header flange you mentioned in regards to the larger exhaust pad? I was unaware there would be any issue there.

Some info here:
273 or 318 or both help
Header flanges are available from many sources, this one is available from Speedway:
Small Block Fits Mopar 273-360 Header Flanges | eBay
They are commonly used by people building their own headers.
The intake manifolds I mentioned are not high-RPM manifolds, and give up very little on the bottom end; mostly due to their small port (273/318 sized) size, and not losing velocity due to the inherent mismatch between the small heads and manifolds designed for the larger 340/360 ports. The bad part is neither is available new, used is your only route.
One other thing you may want to consider in your build: you mentioned using thestock crank. While it's a good unit, depending on the transmission you want to use you may want to consider using a later model 318/340 crank- if you plan on using a later transmission ('68 and up) there are differences in the crank flange and the pocket for the convertor nose that would best be addressed ahead of time. If using a '67 and earlier trans., this should not be an issue though.