educate yourself by reading this several times...
http://www.amrca.com/tech/tuners.pdf
buy several cylinders and twice as many pistons (and rings), then get on ebay and order some of these...
https://www.ebay.com.au/itm/USA-Sal...=item3ab8321a5a:g:em8AAOSwa~BYP4JE:rk:27:pf:0
dont waste your time with a dremel. they are useless.
you port the CYLINDER, not the head.
when it comes to changing port heights, trim the piston FIRST, test it out, then port the cylinder to the new timing, with an untrimmed piston.
be careful with the intake port skirt trimming. youre better off making it wider in the port to keep the same timing, but giving more area to get more air in there.
transfer matching, angles of transfers, flow of gases...
porting an engine is down to imagination in visualising the gas flow, being sensible, only making one change at a time, plenty of testing, and experience.
run straight intake and exhaust manifolds to analyse any changes in performance.
then tune the manifold to suit the intake timing, and, if youre that keen, design and fabricate a tuned exhaust to take advantage of the transfer/exhaust timing.
throw all the bling at it you want. none of it fixes the issues with port timing though. that you have to do yourself, and has much better results than silly anodised alloy bits.
yes, expect to destroy five or more cylinders in the learning process.
its an idea to get a cast iron sleeved cylinder so theres no problems with chrome plating no longer running into the ports and protecting their edges... and its hard to destroy a cast iron sleeve when something lets go.