4: The powerlifts are ASSISTANCE lifts now
You know...like this
Once again, this is simply about a paradigm shift, and most ex-powerlifters don't like to make this one. You can still do the powerlifts as a strongman, but you have to realize that these are now ASSISTANCE lifts, not main lifts. Your bench is helping your press, your deadlift is getting you stronger on a variety of different deadlifts, and your squat is developing some general lower body strength.
What tends to bug ex-powerlifters here is coming to terms with HOW assistance work works in an overall program. Reference my previous writings on the topic, but to summarize; all that matters is that your competition lifts go up. Sometimes, this means that your assistance work takes a dip so that your competition lifts can go up, or sometimes you drop the assistance work to allow better recovery from the competition lifts, but either way, the assistance work has to take lower priorities. For guys that used to live and die by the big 3, this can be a tough pill to swallow. Just know that your powerlifting total dropping is immaterial to your success in strongman and, should you one day decide to return to powerlifting, the time spent training other angles and muscles from strongman will make it so that your powerlifting total quickly matches and surpasses your previous self.
5: Leg Drive
In fairness, anger was about the only emotion I felt trying to figure out leg drive
This is a quick and dirty one, but basically, leg drive on an overhead press isn't the same thing as leg drive on a bench press. Most ex-powerlifters that did any sort of overhead work tended to stick with strict pressing. It was a logical choice for assistance work for bench, as both are strict movements and typically overcoming the bottom of the lift is the most difficult part. This typically means you come into strongman with a strong strict press but a garage overhead press in total because you're losing out on leg drive.
You most likely have some strong legs, so you just need to learn how to utilize them and get the most out of your leg drive. I'll say what worked for me was changing how I thought of it. It's not "leg drive" as much as it's "body drive". You're using your legs to throw your body into the bar to pop it off your shoulders. Try to drive it as far as you can before taking over with your shoulders.
6: Technique techique technique
Yeah, Supes might be strong, but can he rope-a-dope?
This is going to be the most difficult thing for anyone coming into strongman with a foundation of static strength but lacking in technique and athleticism. You're going to be able to muscle your way through most of the events on a local show, and maybe even win, but one you start reaching national level weights and beyond, your strength won't be enough. Don't wait until THEN to start learning technique on the implements. The sooner you start, the faster you'll get better.
I know how hypocritical this sounds coming from me, but even I am trying to get better at this sport. As an extension of the above point on leg drive, learn how to get better at moving the implements. This is sadly going to mean you need to go LIGHTER with the implements in training so that you can actually learn how to use the technique. I wrote my piece on drilling the continental ("Continental Crash Course"), and this was the exact protocol necessary. Start light, learn the technique, gradually get heavier, and you will eventually be able to surpass the weights you were using back when you were just going full on Ogre mode.
7: Don't lose all that static strength
Yeah, this is sorta like how my first year went
So after all this time I've spent harping on now just relying on that static strength you built from powerlifting, allow me totally reverse course and talk about how awesome that static strength is. Strength takes a LONG time to build. It's why there are so few strong people out there. It's no fun grinding your way through training sessions for years on end, but if you manage to do it, you have a serious advantage over those who haven't gone through this process. With this strength, you CAN just ogre your way through an event if push comes to shove, and when fatigue sets in you can get by with crappy technique, whereas other folks have nothing left.
This is why you can NOT lose this strength. It's very tempting when you transition from powerlifting to strongman to go full in, become a technique master, learn the jerk, master your footspeed, develop the conditioning of a workhorse, etc etc...but if you forget to keep your static strength, all you did was trade off weaknesses. Powerlifting wasn't "bad" at all; it's just not adquate right now, but that doesn't mean you need to completely throw out the baby with the bathwater. Those things you did to build up all that strength still work, you'll just need to strike the balance between doing enough to keep and still build a little static strength while being able to actually become a better strongman.
You're coming into the sport with an advantage over someone starting from scratch. Don't give it up.
As always, ask any questions you have, and thanks for reading!