I dont think he's dyno'ed it lately so I dunno right off...Id guess around 700 but I could be way off. The 4.3 V6s are low rpm grunt/tractor motors so they dont scare ppl with hp numbers.....torque on the other hand (which most ppl ignore ) is another story . With the addition of the NHRA legal cage Id say the truck is a little heavy (~3700lbs with driver?) so plugging the weight/et/mph into one of the on line perf calcs would prolly get you in the ball park on what kind of power he's making I would think.

Keep in mind those arent street tires he's boiling in the pics either. Those are M/T slicks on all four corners .