Could anyone recommend me Electronic Distributor Conversion Kits for 1963 225 valiant?

Op did say 63 slant.
Pertronix is a sure fit and easy install.
In post# 12, the OP is considering a 1970's distributor, hence my comment that Pertronix won't fit. For such an e-distributor, a GM 8-pin module & coil is probably best (85-95 V-8), many posts and TrailBeast here kits the parts for those afraid of junkyards.

Re post #18, no hate, but I think there is no HEI big cap for a slant six engine (sorry I can't access the link).