I had the same experience when I installed my Edelbrock #7803 chain with the MP tensioner on my 340. I may have installed it a little differently than Don but I too had some issues with the tight clearances. I put the chain/sprockets on first, then with a big flat screwdriver, I pried the chain over and then got the tensioner "started" onto the locator pin. Then I took a soft blow hammer and then knocked the tensioner until it went on. I will admit that I thought that the locator pin was going to break off but it did not. Then I had to do it again after I degreed in my cam . It went on the second time too the same way and the locator pin still did not break