What camshaft should I use?

John Martin said

It runs a 54 jet in the Holley 1920 right now, it gets 10mpg. I had a 55 and it got 7mpg I had a 56 and it got 5mpg. Something is seriously wrong when a 440 gets better fuel economy than a 225.

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Well I don't have a crystal ball... but there's a couple things that could be going on here, the distributor...make sure the advance weights aren't stuck to the plate....the other is the economizer valve in the carburetor... which is probably more common than the advance plates being stuck so check there. Does it whistle at idle.?
Lastly... Check that little exhaust manifold butterfly below the intake manifold.dl Does that open all the way or is it stuck partially open and not allowing the exhaust out...

Typical slant wors.
Other is the nylon distributor gear failing.
I have lost teeth so many on those with aftermarket cams and some 5500 rpm 1 st gear down shifting. Lol