I used Portland Engine Rebuilders - I see a lot of Larrowe's stuff in their as I believe they do most of his machine work as well.
They built a 270 GMC motor for me and did a great job. I have put over 10,000 miles on it in the last 2 years and it has been a sweet running motor.
Balanced and J&E 9.5:1 compression pistons, recentered rods and excellent head work with moderate porting, small block valves and very nice work all the way around.
They assembled the crank/rods/pistons/rings and valves/springs and I picked it up in two plastic bags.
The only thing I didn't anticipate was that the small block valves were a little short and I ended up cutting the bottom of the rocker arm stands about 0.030 inches to get the rocker geometry right.
Overall I am very happy with them and wouldn't hesitate to use them again.
1001 SE Hawthorne Blvd
Portland, OR 97214-3610
(503) 230-1276
http://www.portlandenginerebuilders.com/index2.html