Has anyone tried these heads?

pauly said
Isn't a 587 head basically the same thing as a J head?

Yep, pretty much. It was used on the early to mid 1970's on the 340 and 360 engines. Many years ago, what, 8-10 years? We were experimenting with the head and they would flow like the ported J head.

.100.........78
.200........139
.300........187
.400........232
.500........270
.600........292
.700........298

The porting is so expensive to get a factory iron head to flow like that so why bother? We haven't done any testing on those heads since back then.