no sound really sounded like it was coming from the rear. The shifter vibrated but not to bad, might be because of the poly mount.

UPDATE: SO the driveshaft was the cause of 99% of the vibration problem. We installed the 4.11s back in this evening and man what a diffrence. We got the car up to 125mph and it a a very slight steady vibration. Its livable with but were going to play alittle more with the pinion angle to see if we can get rid of it completely.

Its so much fun to drive and cruise in now, o and really fub when you smoke the tires down in third going 70....alittle scary too

 

I bet the DS is the cause of 100% of the vibration... they balanced the DS at 2500 rpm...you are currently spinning the DS at 7,000 RPM....This is rather close to the critical speed of your stock DS (the speed at which the DS grenades a take a lot with it) You may want to consider buying a DS rated for that type of speed.

http://www.streetortrack.com/Custom-...-pr-16159.html

These guys sell some that will run true past 8000 rpm....I think thats what im fixing to get.

Of course a better pinion angle can't hurt if it does just take the shims out...totally worth trying.

-Gun

 

i'm eyeballing the denny's driveshaft for mine. you get the slipyoke there with it and that has the advantage that the whole thing will be balanced, not only the tube. further I believe that S&T will just order them off some DS crowd, where with Denny you get it straight from manufacturer, with accurate measurements needed.
I'm positive my driveshaft is off as well. I bought it 2nd hand of ebay and the old one (which had no problem) didn't fit because of the 1210 u-joint holes in the back. So I couldn't crosscheck.

Best of luck!

 

I might get it from Denny as well....I haven't decided yet..

-Gun

 

check out : http://www.dennysdriveshaft.com/c124...iveshafts.html
their street rod shafts are for everything under 500HP ... usually they take 2 weeks to manufacture as they always have a huge backlog. but so far everyone seems to agree that it's well worth it

 

Ohhh that 3" Al one for 350 looks nice....The price is very competitive as well.. I think you have effective swayed my decision

-Gun

 

ya. they have one of them with my name on it as well. comes with yoke and u-joints. can't beat that :-) best thing is you give them exact measures via their measuring charts and whatever they send you will match perfectly

 

Well the vibration is back more than ever. We ended up installing a new Currie 9" with 4.11s, as well as a steel Mark williams DS thats balanced to 7,000 rpms. Got it all put in and the vibration was terrible!!!!! We noticed there was only o balance tab on the front of the DS.

Measure it with a dial indicator and it showed to be .023 off at the yok and .026 off at the center. So we packed it back up and sent it back were he charge us freight for thier mistake. Got it back and and its still the exact same off at the yoke and center of the DS. The vibration is calm anywee under 50 but at crusing speeds it like a pulsing vibrator!!! This is a big headach....

 

so with the stock DS and 8" open rear end it was smooth to 120...right?

You got a new DS and a new rear end and now its really bad?

Where did the axles come from? Could one be bent? If it was great to 120 before and now its crap at 50 it cant be the pinion angle...Assuming it didn't change any.

Check for a bent axle.

-Gun