Your budget ...to spend maybe 1k$ for pistons? ....How much compression do you want ? .... the OEM "industrial" 413 has a pathetic feeble compression ratio. Some who have actually run the figures say it is closer to 6.5 than it is to 7 to 1.

My initial plans are to set this motor up to pull as much as 19,000 lbs ...and run premium fuel - if I have to. YES ..I am talking about using those-heads with that huge water-pump. Those heads are KILLER for a tow-rig.

Cam ? ... I am still collating on that. I am considering a hyd roller - high-lift, fast-rate cam .. but my concerns are valve-spring life.