318 Input and help...please
You need a car oil pan
You can get a pushrod measuring tool. A place like huges engines will rent you the tool and take the rental price of the purchase price of pushrods through them.
Mancini racing also sells the tool.
A good and reasonable priced balancer. An be had from MoPar themselfs. It will be an OE replacement part, but it is a excellent unit.
Carb style, IMO, with a cam that size, I myself would look at a Holley with A 4 corner idle. Not a basic Holley.