400 Gross power?

rumblefish360 said
@RustyRatRod besides the compression ratio of the 400 dropping and the bigger bore, did the big block change much during the smog years in the major parts vs the earlier 383? Things like valve sizes and camshaft?

Not to my knowledge. Once they got the open chamber head, I think that's all they pretty much needed for emissions as far as hard engine parts.