My 400 is totally whipped. I picked up a rebuilt 351m shortblock. I have a 1yr old balancer on the 400. According to Oreilly's website my 400 balancer is listed for a 351m if it is stick shift. With an automatic it lists another balancer. Would I be able to really use this balancer without causing problems because I have an automatic?

 

I used the same balancer when I swapped from an auto to manual and then back with no problems.

 

You know that's an interesting question. I've seen the same part number for all 351m and 400 engines but that can't be right. The cranks are different and of course a flywheel vs a flex plate it would seem would make a difference.

Anyone have original part numbers for the various applications?

 

According to Ford's 1980 - 1989 Master Parts Catalog the transmission didn't matter. One damper for the M and one for the 400. (Look at the green and blue highlighting and disregard the yellow and red.)

 

Both cranks have the exact same 28 oz. imbalance regardless of stroke.
The flywheel and flexplate are both neutral balance so the same damper should work fine on either set up.

 

Thanks for the input. It seemed weird when I looked at that on their website. I'm gonna use it. Now I'm going to move on and decide if I want to change the cam before I put it together. It has a new original grind cam in it, plus the stock timing chain. I have the stand up chain that was in the wasted motor, it only has around a 1,000 miles on it. So I may get a summit 5200 cam and use the stand up chain. I'm just wondering if I should update the valve springs so I don't have a bind issue. Is that exhaust side to much lift for the stock springs?

 

Take the stock springs to a machine shop and have them tested, chances are they have lost most of their pressure and need to be replaced.

 

The roller tip should be just shy of the valve tip center to start and then move over center and back with lift/release. Push rod length will determine that.

Interesting on the balancer parts numbers. thanks for the info.
There must be some difference however or there wouldn't be two part numbers.