Jerry is probably right, but it is possible that a simple valve adjustment too the cam makers spec(!!)will fix that problem, especially if they are solid lifters. While it has been way too many years since I've even considered a solid camshaft, these were the standard for virtually everything until the '50s/'60s (think Ford 'Y' blocks, 'I' block 6cyl GMs, MoPar 6cyl flatheads and more). Yeah, they can tick, but rattle like a diesel? Heck, not even Ford's 'vaunted' and radical 7000 K cam and kit in my 406 made any more noises then make barely hear-able sounds