[kwmech]

Never have I seen a 400 with a 1.76 intake valve, But what I would do is just get a good pair of 350 heads and have them gone through with the 1.94s and have the exhaust valve opened up to the 1.60. The 350s will have to be drilled for the steam pocket holes, but the machine shop can do that without blinking. I'd get the corvette rams with the 2.5 opening and work the exhaust to a single 3'' pipe with a dynaflo