New Motor bearing?

If its a stroker the block will have been notched for the rods to clear. The bearings should be fine as long as nothing is rusted.
If its a aftermarket crank it will be 20 oz imbalance. Only stock 5.0 is 50 oz Almost all aftermarket parts are 20 oz.

If it were me....
(and I'm probably different than most)

I would tear the whole motor apart to check everything...
If the seller didn't know the balance, then what else does he not know?

Have the counter balance verified by having your flywheel and balancer balanced with the rest of the rotating assy... maybe $200

Verify the bearing clearances, and that the bearings were lubed before assy.

Basically, assume nothing about the previous owners engine building skills....


just me though,
jason

Good advice by Jason, as always. ^

You could probably get away with popping off a couple of main and rod caps, to check clearances, without taking the whole engine apart. As for knowing the balance, well... that would require a complete teardown. Does the previous owner know who built the engine? Often times, you can contact the builder with the buyer's name, and they can tell you what you have, and possibly give you a build sheet that lists all of the parts used and their clearances. If the caps are dry, now would be a good time to add some assembly lube, or at the very least a good coat of oil. Whatever you choose to use is going to be washed away at the initial priming and startup anyhow.

5.0Droptop said:

If its a stroker the block will have been notched for the rods to clear. The bearings should be fine as long as nothing is rusted.
If its a aftermarket crank it will be 20 oz imbalance. Only stock 5.0 is 50 oz Almost all aftermarket parts are 20 oz.

Click to expand...

28oz, not 20oz. All aftermarket stroker cranks that I have seen are 28.

No sequence to the main caps. You should inspect the mains and rods though. I have a motor sitting on a stand with less than 500 miles on it, built by a reputable shop here in Phoenix. The bearings were trash, the crank had to be cut and the balance was way out of whack. 200 for a balance is about right but there is a charge for removing and remounting the pistons so keep that in mind. I would go through the whole thing from bearing cleareances and ring gaps to pushrod length, cam timing and valve springs.

Keep in mind when you take off the rear cap you need to use a LIGHT coat of RTV on the block from the outside edge of the cap to just past where the seal sits. If not you'll seep oil.

As far as the balance goes you can do a stroker in 50 or 28 but I've never seen one done to 50 oz. If you can get a part number off the balancer you may be able to look it up and see what it is.