Nobody has answered if it is an HEI? Reason I don't know is cause I don't have anything from GM that new ...
If HEI it could be one of two variants. Plain old HEI with vacuum advance and HEI that is ECU controlled. In either case, what usually happens is that the coil gets hot and the epoxy melts, the windings touch and bingo, there goes the module. Put in a new module and it will fire, just to take it out again next time it gets hot ...
I typically use 990 modules and Pro-Form coils. Yeah, they are Chinese, but they work well and most ignition parts are now Chinese - even GM labeled stuff.
http://www.ebay.com/itm/Proform-66943C-High-Performance-GM-HEI-Ignition-Coil-/201644536814?hash=item2ef2f373ee:g:XkQAAOSwV0RXrbeq&vxp=mtr
So there are two ways to go. One is to buy two modules. Get some heat sink paste (not grease) and install one in the existing dizzy. Keep the other in the glove box. If the coil is prone to shorting, it'll pop that first module. Install #2 and drive home. Replace coil ASAP. Or, just do both up front
Also, you can replace the high resistance "button" under the coil with a low resistance one. Prolly won't bother your radio much, and it will keep the coil cooler. The factory button gets quite hot ...
Of course all this is after you made sure you have no spark. The way to test that is to jump 12v direct from the battery to the HEI power feed bypassing all the switching in the cars systems. If you have spark then, it is in the dash, a safety circuit, a blown fuse, somewhere else ...
And, whether we like it or not, the reason the Chevy dizzy is at the back is because of the cross-member and the oil pan/pump location. The dizzy could be anywhere. But the sump and oil pump can't be economically relocated ...