AUTO TO 4 SPD

The early As came with a 9 1/2" clutch/flywheel and a correspondingly smaller bellhousing. To use a 10 1/2" clutch with the larger bellhousing you'll run into many of the same issues as trying to fit a 727 into the tunnel; i.e. pounding the firewall/floorpan flange flat, and lots of judicious clearancing with a BFH. Then go on a mission to locate the elusive early A 4 spd. hump. Check Brewer's for linkage, I believe they carry modified/custom pieces for the 10 1/2 into early A swap. If you're going to use a scattershield, expect all the above issues to be magnified. Plus there will be issues with the exhaust; early A headers and clutch linkages LOVE trying to occupy the same real estate. Even with a hydro. There's just not a lot of room in there.
Good Luck!