3g kit for 1980 4.9

does anyone sell a kit with everything needed to do the 3g alternator upgrade, closest ive seen is this but the pulley is wrong

/Mustang-SVE-Alternator-130-Amp-QYAiABEgJBxPD_BwE

You don't need a regulator. The 3G is internally regulated.
3G's never came with a V-belt pulley (they started in the '90's) but you can swap your existing pulley right on to the 17mm shaft.
In some cases you need a thin washer. 5/8" usually fits.

I do believe the 4.9 alternator bracket best fits an 8.25" C-C mounted 3G.
I don't own a 300 but there are a number of others here on the forum who do, and have 'upgraded' to a 3G.

That would not be this (7") one for the Windsor motors.

thanks ill check it out