i was wandering if anyone has used this balancer
http://www.summitracing.com/parts/SUM-C4270/
any input would be nice on weather it is worth the month or should i just go with there no sfi one

Harmonic Balancer Construction (Elastomer) Its SFI approved so thats good but still uses the rubber ring^^^^^^^^^^, I like the ones that are liquid filled. I say get it,better then OEM

It has a snap ring that keeps the rubber from slinging out. There worth the money if you are making good power or turning high rpms.

what about lining it up with the pullys so the belt tracks straight are the spacers that come with it cheap ones or are they made of good steel

I know professional product uses a spacer thats the one i got on my car now, I also have a fluid dine H/B thats liquid filled and uses know spacer, the summit one i have no clue. To be SFI approved "i think" it would not have a spacer.

Get a stock replacement sfi approved balancer the ones that use spacers are crap! No belt issues using the oe style! Sfi is just a race spec.
Here's a starting pn. PIO872030

is there one like that but where i can change out the weight for if i swap in a 351 i can just change the weight also should i just get a no sfi or the sfi balancer

The only thing you use a 50 for is a 302-310 cuin a stroker or 351 will be a 28oz. I have seen those but haven't used one so idk can't answer that!

I've been using that part for 3-4 years.
Not a bad deal for the money.
If you need spacers just go to Ford Racing and get them.
I don't need any as I only run an alternatoer off the belt and I use a 'V' belt.........