Mark,
I know the 428 and 427 blocks are totally different animals but her is my experience from two years ago.
I had a 428 bored .060 that I bought as a completed running engine. I paid $4400.00 for it and I assumed it was built the way it was described to me. First mistake. But the engine always ran hot even in 70 degree weather. If I sat at a stop light more than a minute my temp gauge was pushing 220 and sometime 230 degrees.
In defense of the engine, the builder had used various parts, two different types of pistons (part were skirted some not) and rods, tolerance were not accurate, and the engine had not been balanced. The bottom line was I had been screwed, blued and tattooed.
My advise on the sleves call or send George Anderson an email and he will give you honest and sound advise. He knows his
stuff very well.
http://www.gessford.com/
Good luck,
Clois