Another Mopar Off My Bucket List - Barracuda Fastback
The pushrods are available in all kinds of lengths. Figure out what you need and then find the closest one they already have in stock. 99% of the time they are an off the shelf item.
By the way, every hyd. lifter I have ever had instructions for says to not fill them with oil. Doing that makes them nearly impossible to accurately adjust static/cold.