[Chevy454]

Interesting info, GMH. So, it looks like there WERE some 291 heads installed in place of the 840s in '69, and they weren't just "service replacements" for the 840s. I am also assuming that the 840s I have came with the 1.88s so they could be used in conjunction with the 291s? GMH: what size valves were in the heads you are talking about.

The machine shop called again today, and said that the heads have absolutely NOT been touched, and that they came with 2.19/1.88s in them. He said he could put in 1.72s, put they wouldn't flow worth a darn due to the downsizing of the seat. He also mentioned that in his reference books, he ONLY shows the 2.19s being accompanied by 1.88 exhuast valves...the 2.19/1.88s are hi-perf while the 1.72s are low-perf and came with 2.06(?) intakes. My local parts guy (MoParts on here) also checked his books, and they DON'T show a 2.19/1.72 combo.

Any ideas?