Re: So i am thinking about building one.
I like my coaster brakes on the bike that has steel rims because the side pull brakes just dont seem to grip the painted steel wheels that good even with the high dollar heavy duty pads I have.
Now if the bike has Alum. rims and it has V brakes that is a very good set up but since the bike you mentioned is from the 70's this wont apply.
A good coatser hub with the best front side pull will do ya pretty good for the braking in my experience and my bike will do between 38 & 41MPH depending on weather and road conditions.
Build it right, all things aligned properly, upgrade fasteners, good solid mounting to the frame with NO rubber or anything else between mounts and frame, good inline fuel filter, better NGK B6HS spark plug and better plug boot & wire and as you go ask plenty of questions here if need be and search the topics in question on the great search tool we have here, there will be some other things like getting the carb tuned properly after you get the bike running and all the mounting and alignment correct, many of us here can walk you through getting the carb. tuned or again all you will ever need to know about this can be found by searching the forum.
best wishes on the build I say do it and have lots of fun and remember patience.....is a huge benefit when doing this project, it atkes a little time & energy to get it all right but it is well worth it in the end IMHO....
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!