The "big cap" HEI that GM used on the 230/250/292 sixes can be modified pretty easily to fit the 216/235/261 engines by changing the depth it plugs into the earlier block, and installing a bronze drive gear on the ones used for the 216 and pre-1954 235 engines with the forged steel camshaft. Personally, I think that setup is ugly enough to make a freight train take a dirt road, and it must be used with a conversion to a 12 volt electrical system on the 1954 and earlier trucks. The 'Pertronix" electronic ignition conversion comes in two versions- - - -the ones that have already failed, and the ones that will quit soon.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!