block identity

[maximum123]

how can i tell between a roller and non- roller 302 block?

[Neighbors]

Externally it might be hard, unless you read the casting date near the oil pan rail. A roller block 'should' be an E5 or E6 casting...

If the lower intake is off, you should see a couple locations that read 'XXX' or 'YYY' in a small arc, about the middle of the block, near where the lifter bores are. Also, you see two small drilled and tapped bosses cast into the block (that hold the spider), on the centerline, above the cam (but again, inside the lifter valley)...