251 in the American M37

[Matt Wilson]

I would call it more of an hub than a balancer that the pulley bolts to, I used the factory piece. Engine has been great with no issues what soever. I usually drive highway around the 60 mph as I live out of town around 30 miles from the city. I would say that if you are building one that BALANCING the rotating assembly is a must for the longevity of the 265 as it has a 4 3/4" stroke which is a long throw in any engine.

Thanks, Superdave. So your hub doesn't have any type of rubber or heavy metal/disc portion that would tend to balance out vibes? Just a plain hub? That's good to hear from my perspective. For my 265, I think I will have the option to use the pulley from my 230 or the one from the 251 donor engine that I'll be receiving soon. The 230 pulley is just a one-piece unit. The pulley is sheet metal and is welded to the hub, no damping capability at all. I don't know yet what the 251 pulley looks like, but the person who currently has the engine says the pulley is not a damper type. Knowing that the 265's came with dampers of various sizes, and not knowing if they ever came without a damper, I wasn't sure if I was inviting trouble by running mine without it (just running a plain pulley), but your experience seems to indicate that it's fine, so that's reassuring.

And yes, I will definitely get a good balance job done on the crank, rods, flywheel, etc. Most of my driving will be around town, but I will also spend some time on the highway at 60mph or so. I have 4.89's in both diffs.

Thanks,

Matt