School me, please: Z-bars

55Brodie

Well Known Member
#1
62 Impals w/348 and 4 speed Muncie

I suspect I have a small block Z-bar as my clutch pedal adjustment rod is adjusted to its extreme. From what I can gather there is only one clutch rod used, bur why would the 348/409 Z-bar be different from a small block?
 

pvs409

Well Known Member
Supporting Member 7
#2
Some comments after making 7-8 conversions PG to stick and restorations of 61 to 63 Chevy’s over the years
  • Mixing years of clutch parts typically does not work
  • The wrong clutch fork and/or lower clutch rod can cause adjustment issues ( to get proper clutch release and clutch free play)
  • Original 1961 Chevy’s are a one year set of clutch & brake pedals and upper & lower clutch linkage.
  • Original 1962 Chevy clutch & brake pedals are one year only set
  • Original 1963 & 1964 Chevy clutch and brake pedals are the same
  • Original 1962 to 1963 upper and lower clutch linkage are the same ( original 1962 upper clutch rods have a slightly different shape/ bends as compared 1963/1964 upper clutch rods but will work the same)
  • Original 1961 Chevy upper & lower clutch linkage has all the clutch adjustment in the lower clutch rod.
  • Original 1962 to 1964 clutch linkage has all the clutch adjustment in the upper clutch rod
  • There are two types of clutch forks and two types of lower rods that will work on 61 to 64 clutch linkage
  • 1959 to 1960 original upper and lower clutch linkage is similar to 1961 upper and lower clutch linkage
  • Using later years 1965 to 1969 Chevy clutch linkage, bell housings and clutch forks on 1961 to 1964 Chevy’s "can cause" adjustment issues and fit problem.

  1. Yes 1962 to 1964 Chevy 409’s had a different Z- bar than small block Chevy’s ( one arm was shorter) -
  2. I think & know that small block Z-bars will work on 409’s if the right lower rod/ pin and clutch fork is used.
  3. I do not like the stock original lower clutch rod/pin and clutch fork ( the design can be improved).
  4. I have started using a different type of lower rod/ pin and clutch fork on my 409’s

I suggest that you post or send me pictures from your e-mail of your upper and lower clutch linkage.
I just solved a similar adjustment problem on a 62 Impala 327 - 4 speed ( the upper rod was adjusted to the end of the threads). I found out that the lower linkage rod and clutch fork were wrong.
 

55Brodie

Well Known Member
#3
Thanks for your reply, Paul.
I am too old, fat and crippled to be rooting around under the car, especially since it functions just fine for now. If something goes haywire I will address it then.
My car was originally a V8, 3 speed manual. I would think whoever did the conversion used the original bellhousing along with original z bar and linkage. Since the dimensional relationship of the clutch components is the same for small and big blocks, why did GM feel the need for different z bars and lower clutch components?
I'm just curious more than anything.
 

Phil Reed

Well Seasoned Member
Supporting Member 10
#4
The difference in bellcranks...small blocks levers are different lengths. The 409 are the same length. The longer length allows more travel for the clutch fork.
Sorry I don't have pictures to show the difference.
 

de31168

Well Known Member
#12
I can't answer your question as to why, but this is a great website i've used over the years for various questions i've had about z bars and what does and doesn't work.

https://www.4speedconversions.com/zbars.html

If you click the different z bars they give you more detailed descriptions. If you think you have a small block z bar, measure the holes and compare to theirs listed for that one vs a 409 one.

https://www.4speedconversions.com/3846881.html

or

https://www.4speedconversions.com/3846883.html

The only thing I can think of is the exhaust or something might be routed differently between engines requiring a different throw. Also useful for if you have headers and need to change your geometry but still want to retain factory location.
 
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