Im swapping a cam in a 340 and decided to put on a tensioner while I was in there. Well, the new edelbrock chain is so tight that I can barely get it on without the tensioner. With the tensioner installed there is no way it will fit. Is this a common problem or is the tensioner designed for engines with chain wear?

Is it a double roller type chain? I know quite a few of them do not require a tensioner, just the oil slinger. On the mags with a cloyes chain I have never run a tensioner and it works great. The chain is so tight new it can be difficult to install.

It will go but like you sa it is tight. I have a set of vice grip type pliers with plastic cups to protect what it is working on and have had to pull out the pin in the ensioner asnd give it a more squeeze while installing the chain. You may not want any women to kids around you whiel you are doing it.

Mike - I had same frustration on the 318. As I recall I wrapped some mechanics wire around the tensioner - looped over to a bolt installed in the passenger's side head ( someplace that would keep the wire in line) and used a screwdriver to twist the wire and suck the plate way the He''ck out of the way . OK way the heck is a lttle exteme - it was still a PITA to get the chain on, but only way I could get clearance. Not real sure if I could have cleared a needle nose vice grip jaw. It sure doesn't go on as designed out of the package!
The Suggestion is that 2 sets of hands are better than one - just make sure your helper didn't have a Garlic Pizza.

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

Same problem on my 340. I installed a Cloyes double True Roller chain and fought to get it on with the tensioner.
I had to have my brother hold the cam in place so it wouldn't bang against that rear plug. Then, I used my fingers to push against the chain and tensioner at the same time.
Once I got the first row on the tensioner I was able to slowly work the chain and gears into position.
It was tough.

I have 3 engines with tensioners. All were line honed as part of the rebuild so it was easier to get the parts to work together.

it will go on just takes a little time and patience.

Hook a wire in so you can pull against the tensioner. There is even a hole for it.

This timing set has 0 slack in it, prying is not an option.
Actually, I have never seen a chain that was this tight. Usually new chains have a little play in them.
I will just hold on to the tensioner and save it for another engine or install it after this one has a few miles on it.

It is really tough. I took a nail and inserted it into the hole on the tensioner arm. Then I used a set of channel locks with a rag around the teeth to pull the arm back away from the chain. When the hole in the arm lines up with the outside edge of the tensioner plate, shove the nail through until it touches the block. The edge of the plate will hold the arm back. Then you have to work the cam sprocket onto the cam. I used a screwdriver to hold the cam forward and tapped the sprocket on with a dead blow hammer. Make sure the crank sprocket isn't seated all the way back as you work the cam sprocket on. Then just work the two sprockets back together until they are both seated.

I've put mine on twice pretty quickly like this. When I tried to install with the original pin in, it would never work. The arm just needs to be pulled back further.

Good luck!

I have noticed some pretty bad wear on the tensioner plate where the cam rubs it...wondering if mopar is using some cheap metal for the plate ....wouldn't doubt it...it will not go on again. I would rather have a little ignition walk than a f%^$&^ up motor!