yes they are the 64 castings, so they are d ports. i'm pretty confident about what the heads are. it's got anedelbrock torquer intake. that seems right for a 455, builds power up to 5500 rpm.
i was thinking it was a 455 after checking the compression we got a high of 188 and a low of 168. that seems pretty high. stock it should have had 10.25:1 if i remember right. with the valve covers off it turns out a previous owner out roller rockers on it. it sounds like it has a mild cam. just a little lope at idle.
the guy that yanks my engines for me sys the heads look too clean to have 5000 miles on them. he thinks somebody missed something when they built it that hasn't completely broken. the plugs were all clean as well, but the piston top look dirty. i told him to go ahead and yank it.
i'll feel better knowing what's going on from top to bottom anyway. hopefully the crank is good and know cylinder wall are fried (compression makes me think not) new rod and main bearings and lifters might do it wonders. the high compression has me a little worried that they may have faced off the heads. if that's the case i'll have to figure out how much stock was removed. would you definitely have hardened exhaust seat and guides put in?
anyway, i'm hoping it is the 455 it was sold as. thanks that answered a few of the questions i had.