Dear God don't ever ship an engine through UPS. I bought my 650 engine off Ebay for $100, shipping was $125 (it was 4 lbs over but they slipped it through). When I got it, the clutch cover was shattered, the breather cover was cracked, and both of the #4 header bolts were sheared off at the head. What a nightmare.
And yes, they will ship over 150, but it will ship freight and not parcel post. That's why the quote is so much more expensive.
I would go with a national carrier and bite the bullet.