Okay, here is some unscientific data using my bathroom scale.

On the front, I went from Cragar Soft 8, 15x7, with 235/60/15 Futura GLS to the Summit 531 alloy, in 15x7 with the same 235/60/15 tire.

Cragar Soft 8, 15x7, with 235/60/15 Futura GLS weighed about 51 lbs.

Summit alloy, 15x7, with 235/60/15 Futura GLS weighs about 43 lbs.

Some other measurements with the bathroom scale:

Chrysler 15x7 police with 235/60/15 Futura GLS weighs about 50 lbs.
Chrysler 15x7 police with 215/65/15 Cornell 1000 weighs about 45 lbs.
Chrysler factory 15x7 steel with 235/60/15 Goodyear Eagle ST weighs about 45 lbs.

Don't take any of that as gospel, because those measurements were made on an analog bathroom scale.

Butt dyno test will probably be overnight sometime. If it works out, I will switch the 15x8 steelies in the back with alloy wheels.