The 400 in my 73 Torino Squire wagon has had a cam shaft and timing set changed. I have found receipts for a 73009 timing chain set, including both sprockets and the chain from Autozone, and an edelbrock 2172 camshaft. I have been reading that Ford retarded the cam timing in 73 to compensate for unleaded fuel. Does anyone know if the cam and timing set that were installed are the correct combination to restore the timing to that of the earlier 400 engines? Does anyone know what the timing would be for a stock 71 400 versus the stock 73 400? I was going to swap the 400 for a 429, but considering the work that has already been done to the 400, I might just leave well enough alone.