Information on a 340 for my 69 dart

Wouldn't want to go much over 15k.....but that's not even problem
A donner car is the way to go
Plans are to drive the car as is and collect body parts but if something comes up I'd jump on it
Has to be a basically stock 340 couldn't sleep at night with anything else
4spd thinking 373
It's a convert so just stock is enough
Want it look like it rolled out the factory that way
Seems like a early engine is better
But if something pops up anything will do