Another BB swap 1970 Dart

67valiant 100 said
That 400 might be one of those super blocks. Strongest factory Mopar block made and super rare and desirable.

Read:

http://www.440source.com/blockinfo.htm

I have a 1975 400 truck block and after it was bored/honed .060 over, the cylinders all sonic check at 95-100 thousands thickness. That #2 main web was huge, almost completely machined.