Problems with Crank Pulley & Balancer

[71Demon340]

I bought a Summit C4277 SFI harmonic balancer and I was trying to line up the bolt holes with the crank pulley and can't get it to work. This is on a 71 340. I have the original steel pulley and what I think is a Moroso aluminum pulley. The bolt holes in the two pulleys line up so they are the same. Seems like the 6 holes in the balancer are equally spaced, but the holes in the pulleys are not. Any suggestions? I was looking at a March Perf pulley and it appears to have one slotted hole out of the six. Would this solve my problem? Thanks for any advice.

 

[63dartman]

You may have the wrong balancer. I looked up that balancer at summit and the application has 21 pages all for 273/318/360......I may be wrong but it's worth double checking.

oops....went back and double checked. There is a selection for the 340 does that balancer have the removable weight on the backside?

 

[66dartgt]

The pulleys on the older motors - prior to 72 (if memory serves me correctly) had a pattern to the bolt holes on them, All you need to do is line up 5 of them and the 6th needs to be filed out with a rat tail to match the pattern.

 

[71Demon340]

Thanks guys. I'm going to call March Perf to see if their billet pulley has the one slotted hole. I really don't want to use the factory steel pulley and the alum Moroso pulley I have is designed so that the holes can't be modified.

As far as the counterweight on the balancer, it does not have one, but there is a spot to add one if needed.

Where can I get the fasteners to attach the pulley? My dad disassembled this motor 27 years ago so I am missing a few of the little things.

 

[66dartgt]

Stock fasteners are 5/16 coarse thread bolts about 1/2 - 5/8" long, they have integral spring lock washers on them as well.