Chevy Nova Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
429 Posts
Discussion Starter #1
Our 66' Nova has a zz4/700R4 combo and the rear end was just rebuilt with all new bearing and an eton posi (373's). The car also has CalTrac's installed.Our problem is that when you pull off from a stop the car begins to slightly shake up to about 40mph. The shake is slight but you can feel it. The shop that rebuilt the rear end said that the angle of the rear end was about 4 degrees (down). He said that 4 degrees was fine but he did not know what angle the trans tail shaft should be at. He thought that our trans had a slight "up" angle but did not measure it. Do any of you guys know what the proper angles for both the transmission and the rear end should be? It seem as if this angle "missmatch" is whats causing the shake. Just as a side note we did not cut the tunnel and we did use one of Bowtie overdrives 700r4 trans supports.
Thanks in advance for any advice.
 

·
Premium Member
Joined
·
4,612 Posts
i have a similar combo and also didn't notch or beat my tranny tunnel.i'm unable to measure the angles but common sense would dictate that our 700r4 tailshafts are in approximately the same height and angle. a good tech buddy of mine told me once that if your pinion angle was to extreme one way,it would cause shudder on acceleration.if it was too far the other way it would cause driveability problems on deceleration.
smarter tech dudes on this site may be able to offer a better solution or some advice.
did you consider checking your drive shaft for straightness and balance?pretty easy re&re and cheap to do.good luck ,thx,cj.
 

·
Registered
Joined
·
3 Posts
hello all im new to the site but i know a thing or too about a thing or too
:beat:
if it was me i would shim the rearend up about two degrees . spicer u-joints say you should have 2 degrees on the u-joints . tha trans angle you want as flat as you can or as close to 2 degrees. it will matter if your car is sitting stock or not .
 

·
Premium Member
Joined
·
1,536 Posts
Hey 63smalltire,
I noticed this was your first post......Welcome to the site! This is a great site full of awesome people and a huge amount of knowledge amongst the huge membership
 

·
Registered
Joined
·
3 Posts
thanks for the welcome to the site,i build drivelines for a living i have been doing so for 6 years now.i build custom bikes and hotrods with my spare time ,
i try to do everything myself from motors to bodywork. i have a 63 nova that i did a 9" with 325-50-15s drag radials . 377 or 410 motor im building both motors now . i did a full frame rear with mono leafs and airbags with the help from friends . this is the best site i have seen for novas, i have been looking at the site for about 6 years now . i figure i might be able to help people on there builds and alot of what you guys talk about helps me .
thanks erik
 

·
Registered
Joined
·
91 Posts
I haven't tried it yet so I don't know how correct it is, but it has made the most sense to me. I've seen it suggested that you set your engine so that the carb is sitting level. This will ensure that the fuel bowls are positioned properly and the floats operate properly. This in turn will set the angle of the tailshaft on your transmission. After this is set, measure it and shim your rear axel so that it is the same angle as your transmission. From there you can make minor adjustments as desired or needed.
 

·
Registered
Joined
·
1,077 Posts
An angle of 4 degrees down is somewhat common on an unmodified floor
with a big trans.
if yours is really 4 deg., the pinion should be 3, maybe 2 degrees up.

if the pinion is down , it will whip & vibrate, untill it hits the ground.
 
1 - 8 of 8 Posts
Top