Well, I have gone over this engine with a fine tooth comb. I cannot find any flaw. All parts look like new. No indication that any part is hitting somewhere. I measured with a caliper and have good clearance from piston to top of cylinder sleeve to cylinder head. The new cylinder head measures the same as the old. Not much else I can do. So I'm going ahead and order the connecting rod. This engine will run or it will self destruct. blw, thanks for the heads up on price. I had written the wrong price and thought it was more expensive. The part is not in stock but I will get an email from Tower when the part is available. I'll update this thread when I get to tinker with this engine again. Thanks all.