Question About Clutch Pedal Push Rod

[pjmoreland]

I have seen two different styles of clutch pedal push rods for SBC trucks. One is mostly straight and the other has a dog leg bend in it. I'm trying to figure out why these two different designs exist. Here's what the parts catalog says for 2WD small block V8 applications:

3889915 (straight):
67 ALL C-MODELS
68 C20, C30 W/307, 327 V-8

3907877 (dog leg):
68-69 C10 W/307, 327 V-8 (excluding C20)
70-72 C-K MODELS W/V-8

I believe all 2WD SBC applications used the same z-bar. Was there a difference in firewall hole location from year to year or a difference in the clutch pedal assembly?

Here are some images of the two push rod styles from this website:
https://4speedconversions-com.3dcart...k_linkage.html

[Jason Banks]

I have the straight one on my straight 6 and have seen the bent on small blocks, not sure about big block.

[pjmoreland]

I removed a complete clutch linkage set from a '67 C20 with a SBC, and it had a straight push rod. I'm wondering if this straight push rod is going to work on my '68 C10.

[RustyPile]

Originally Posted by pjmoreland

I removed a complete clutch linkage set from a '67 C20 with a SBC, and it had a straight push rod. I'm wondering if this straight push rod is going to work on my '68 C10.

Hook it up and see if it works..

[pjmoreland]

Originally Posted by RustyPile

Hook it up and see if it works..

Yep. I'm being lazy

[pjmoreland]

I installed the clutch pedal and the bellcrank so I could test the straight clutch pedal push rod. It does not fit. Even though my clutch linkage components came off of a 1967 C20 with a small block V8, I'm wondering if this bellcrank might not have been on that truck originally. I've found some photos of bellcranks where the upper arm angles toward the engine, whereas mine angles away. Seems like the straight push rod would work a bellcrank that angles toward the engine.

I also discovered that the '67 bellcrank frame bracket will not work on my truck. I had to install it backwards in order to barely make enough room for the bellcrank. I'm also finding photos of brackets for SBC applications that face away from the engine instead of toward the engine. I think I need to get one of those brackets, too.

[RustyPile]

Originally Posted by pjmoreland

Yep. I'm being lazy

If they only knew......

[RustyPile]

I have the pedal assembly, bell crank, frame bracket, upper rod, and lower rod from a '70 C/20.. The rod I have is the curved one with a flattened area near the lower end. My bell crank is configured like the one installed on your truck, so I would assume you need the curved rod.

Is that second picture you posted, one that you sourced from elsewhere, or a picture of what you have.. It's possible the frame bracket was just "posed" wrong...

[pjmoreland]

The second picture is just a random one I found on the website. I believe I need a bracket like that one. I tried mounting my bracket both the way it was on the donor '67 and backwards, but it doesn't work either way. It has a jogged section in the middle that limits how far away from the engine it can be. Here's my current bracket.

[RustyPile]

Something else comes to mind... Is it possible that in the past, an accident happened and the frame rail has got pushed over toward the engine a slight amount, just enough to cause these parts to not fit exactly right????

[RustyPile]

My '71 was born with an I6 and tott.. As you know, all that's gone and in it's place is a 454/TH350.. The bracket is still in place on the frame and looks like the one on your truck..

[pjmoreland]

Originally Posted by RustyPile

Something else comes to mind... Is it possible that in the past, an accident happened and the frame rail has got pushed over toward the engine a slight amount, just enough to cause these parts to not fit exactly right????

It's certainly possible, although I see no other evidence that the frame rail is tweaked.

I think I might have found an explanation for not having enough room between the engine and the frame bracket for my bellcrank. I believe '67 SBC trucks used the same shorter bellcrank as 6-cylinder trucks. Here are the 2WD bellcrank applications listed in the parts catalog:

3913127 67 all C models, 68-72 C Models W/6 Cyl, 68 C20 C30 with SBC
326548 68 C10 C20 models with SBC, 69-71 C models with SBC

Based on this catalog info, it appears that all '67 models used the narrower 6-cylinder bellcrank. That would explain why the bracket I got off of the '67 SBC C20 at the wrecking yard had the contoured frame bracket that faced inward. It doesn't explain how I ended up with the longer 68-72 SBC style bellcrank from that same truck though. It was just sitting loose in the engine bay though, so my guess is that it was actually from a different truck.

As for the brackets, here are the two styles listed in the catalog:

3889916 67-68 All C models, 69-72 C models with 6 cyl
6261878 68 C10 C20 models with SBC, 69-72 C models with SBC

The two brackets appear to cover the same applications as the two bellcranks. The contoured bracket that faces inward is for 67-all and 67-72 6-cylinder applications.
1968 appears to be a crossover year because it is listed under both parts.

https://4speedconversions-com.3dcart...m/3913127.html
https://4speedconversions-com.3dcart...om/326548.html

https://4speedconversions-com.3dcart...m/3889916.html
https://4speedconversions-com.3dcart...261878_r1.html

[pjmoreland]

Originally Posted by RustyPile

I have the pedal assembly, bell crank, frame bracket, upper rod, and lower rod from a '70 C/20.. The rod I have is the curved one with a flattened area near the lower end. My bell crank is configured like the one installed on your truck, so I would assume you need the curved rod.

Is that second picture you posted, one that you sourced from elsewhere, or a picture of what you have.. It's possible the frame bracket was just "posed" wrong...

I don't think it is posed wrong because the funny notch that accepts the bellcrank ball joint is notched the opposite direction from the contoured 67/6-cylinder bracket.

[pjmoreland]

This may be a better way to go than trying to repair a worn out original.

https://www.classicparts.com/mobile/...ctinfo/90-834/

[CAMAROBOY68SS]

The rod shape was dependent on where the motor was located originally. Usually I6's have the straight rod. My truck was a 292/4 speed truck. So the motor mount stands are in the rear position. The Z bar mount on the frame was also different and located in different spots depending on the engines mounting. My truck still has all the original I6 brackets and rods in it for my 4 speed as my small block is still in the I6 rear mounting location. If your motor is in the normal 2wd V8 location then you need the bent rod, the forward frame mount and then maybe the bolted on ball mount on the motor.

[pjmoreland]

Yep. I've got a 2WD SBC in the forward position. I'm trying to track down the correct frame bracket right now.

[pjmoreland]

A friend found this bracket, so I'm heading out to go pick it up from him.

[jumpsoffrock]

Oh wow they're riveted to the frame? I figured they'd be bolted.

[pjmoreland]

Originally Posted by jumpsoffrock

Oh wow they're riveted to the frame? I figured they'd be bolted.

At least we know for sure which way it is supposed to be mounted!

['68OrangeSunshine]

Originally Posted by pjmoreland

I have seen two different styles of clutch pedal push rods for SBC trucks. One is mostly straight and the other has a dog leg bend in it. I'm trying to figure out why these two different designs exist. Here's what the parts catalog says for 2WD small block V8 applications:

3889915 (straight):
67 ALL C-MODELS
68 C20, C30 W/307, 327 V-8

3907877 (dog leg):
68-69 C10 W/307, 327 V-8 (excluding C20)
70-72 C-K MODELS W/V-8

I believe all 2WD SBC applications used the same z-bar. Was there a difference in firewall hole location from year to year or a difference in the clutch pedal assembly?

Here are some images of the two push rod styles from this website:
https://4speedconversions-com.3dcart...k_linkage.html

Dog Leg = V8.
Straight = L6.

[pjmoreland]

Originally Posted by '68OrangeSunshine

Dog Leg = V8.
Straight = L6.

Yes, except for '67, where even the V8 was straight. Just another thing to add to the list of unique '67 features.

[1967GMCC20]

I'm removing my 67 clutch pedal and push rod now it has Automatic. Mine was V6, Might be different from Chevy.

Looking for plug that fills clutch rod passage.

['68OrangeSunshine]

Originally Posted by pjmoreland

Yes, except for '67, where even the V8 was straight. Just another thing to add to the list of unique '67 features.

OK. My '67 K/10 got converted to automatic by a PO.
BBC 454/TH350/NP205.
Probably originally a 283/SM420/T221. But I'll never know.

When I could not get my OEM straight Upper Clutch Push Rod fixed, and LMC's repop was wrong for a '68 C/10 Stepside w/292, I had my machinist thread a steel rod for heim joints.

Dog leg type on the '71 Jimmy w/350/SM465/NP205.

Wow! Post #6666

[RustyPile]

Originally Posted by 1967GMCC20

.........................Looking for plug that fills clutch rod passage.

There are very few reproduction parts not available for our trucks.. Most searches fail because the wrong terminology is being used.. Go to Classic Industries and search "clutch rod delete plug"..

[pjmoreland]

Originally Posted by RustyPile

There are very few reproduction parts not available for our trucks.. Most searches fail because the wrong terminology is being used.. Go to Classic Industries and search "clutch rod delete plug"..

The clutch hole plug GMCPauls sells for 67-70 trucks (the pop-in style) is OE and is made by the original manufacturer. That's what I've got on my truck, although I will be removing it soon.

https://gmcpauls.com/rubber&ws1.htm