Gerry - while you may love that '66 and the 429, a local guy did a '65 with your 429's big brother, a 460 - big time. Redid the shock towers and who knows what else to make it fit. Ran like stink - in a straight line. The downfall - it wouldn't stop even with disc's in the front and a 9" w/drums in the back. It also wouldn't turn. The car - scrap iron and probably now part of a new Toyota or Honda.

Unless you just use the body with a full tube frame, a decent engine set back and someone else's steering and suspension, you will be disappointed. As Tech said, a nicely warmed 302/5.0, even one out to 331 or 347 if you really need to go fast will probably be all that car chassis can take without significant reinforcements. You can then use a C4, keep the 8" rear end or upgrade to the 9" or an 8.8 with the integral e-brake and disc's.

Whatever way you decide to go, make a plan (on paper), do your research and decide how much you want to spend. Dollar wise, 'playing' with cars is no longer a poor man's past time. And as far as help, for sure someone here will give you some, regardless of what you need