Small port heads, big port intake. How bad?

If you put a mechanical secondary 4-bbl on it with primary's that are smaller than a comparable 2-bbl you are looking at, you should be able to get better gas mileage as long as you keep your foot out of the carb.

Then you have the 4'bbl whey you want to 'get it' and can be miser when trying to doso.

Just my .02.

But how much does the reversion at the head to intake transition hurt me?

It has a Carter Composition Series carb, no idea what size.