[Barry_R]

This is the 429/460 section. But since we're talking factory style FE 427 data I can add to the thread.

I have had a couple recent very OE style 427 2x4 engines on the dyno. The first one was mish-mash of decent parts. Already .040 over 1963 block (paper thin), and had +/- 9.8:1 compression, a pair of 428 CJ heads with a decent valve job but no porting. A factory medium riser 2x4 intake with two 600 Holleys. Cam was a Comp 282S solid with .571 lift. Engine made 426 horsepower (going by memory - I might be off by 2 or 3).

Engine number two was a 4.250 bore marine block (that had been disguised as a side oiler and sold as such to the current owner). Stock stroke. Had a pair of nice 427 medium riser heads with a very good valve job and a bit of hard to see/stealth pocket work. Compression was 12.5:1 with a custom light ring pack. Cam was a .525 lift solid roller running stock valvetrain - again stealthy, but they are breakage prone and will be replaced this year. A pair of Carl's repop cabs on a factory MR 2x4 intake. Engine made just over 500 horsepower with cast Fairlane manifolds.

Based on this experience I'd say it would be very hard to hit 500 with a stock 427 factory combo...