Stroker cranks take narrow h series full groove to clear the radius at fillets, h beam rod bearings require narrow h series as well.
You can narrow them yourself, but if you're not setup for it... it's a lot of time.
If you use regular main bearings with a radius journal... it wont have any thrust clearance, n will have worn edges only on the bearings.lol I remember my first go at the 4" arm, learned many things.
