Can someone help me identify the heads on my 440. The cast numbers appears to be 2406516. The 6's and 8's are hard to tell the difference but I'm asuming it either a 516 or 518 scince I see no heads with a 2408pre-fix. My problem is these heads have a 1.74 exaust valve and measure 83cc chamber. From what I can find the 516 would have been a 73cc chamber and the 518 would have had 1.88 exaust valves. The chambers do not appear to have been altered. I could under stand enlarging a 516 valve to a 1.74 but the chamber still should be 73cc. I'm sure there not max wedge 518 because the exaust valve would have been 1.88 and the intake runners appear to be of a normal head. Anyone ever here of this comb? help Mike