touchy gas pedal

[kingchris401]

Hey everyone, I've been on this forum for a few years but never really got involved until now. I just bought a 67 the day before Halloween. It's super rusty, loud, very unapologetic, and in your face. It's got a truck load of problems but seems to run fine mechanically. it has a cammed 350, 4 speed, 750 carb, and kegs for fuel tanks...

One thing I need to fix while I wait for the tags would be the gas pedal. I drove it a half mile up the road to the notary and couldn't stop bucking from the pedal being too sensitive. It seems like it's set up to be mashed to the floor at all times. Plus the springs are cut so it's like riding in a bouncy castle. I was just wondering if anyone else has come across this issue before. I thought about changing the length of the bracket on the carb or maybe changing the springs on the carb to softer ones. I found tons of stuff online about this but nothing for an old rusty truck. Mostly just new stuff.

So anyway, any help at all is much appreciated!
Chris

[ratty69]

Have you looked at your throttle linkage? 67-70s had a solid rod linkage to the carb, and it might have been butchered when the carb was swapped.

My 69 acted like that when I got it. When the PO installed the Edelbrock carb, he tossed the linkage from pedal to the carb. He installed a throttle cable bracket, and cut off a throttle cable and just looped it through the pedal and crimped it together. Combined with 2 return springs and it was touchy. I replaced the whole mess with a proper pedal and cable.

I used this thread for inspiration, but different parts:

http://67-72chevytrucks.com/vboard/s...00#post1383300

[LongBox]

On my 69, the carb has more than one hole for the throttle rod. You can move the rod to different holes to get a different response. See the picture:

[kaycee]

WOW REALLY , You need a spring on it from linkage to front of engine

[michael bustamante]

if you could post pics that would help immensly. if any parts are needed im sure the guys here or myself have what you need.
also if you wanna get rid of those kegs id be interested

[hounddogs!]

Something else to check would be how freely the accelerator piston moves in the bore. My Buick's AFB acted this way - moving from a 3/4" pump to 11/16" helped immensely. I really think that the apron was just too tight and wouldn't start to move gradually. It was either on or off.

[kingchris401]

Originally Posted by ratty69

Have you looked at your throttle linkage? 67-70s had a solid rod linkage to the carb, and it might have been butchered when the carb was swapped.

I do have the solid rod. I took it apart at the carb and it did move freely.

Originally Posted by LongBox

On my 69, the carb has more than one hole for the throttle rod. You can move the rod to different holes to get a different response. See the picture:

I have different holes also but mine is at the farthest hole. It seems like I need to make it farther from the pivot point. So I thought about making a braket to make it longer but then it wont fit under the air cleaner.

Originally Posted by kaycee

WOW REALLY , You need a spring on it from linkage to front of engine

It does have a spring from the carb to a hose clamp on the radiator hose... It has a lot of tension on it too. The PO was a super redneck from deep back in the woods lol. I'm finding that a lot of this stuff is Jerry rigged like that. I tried taking it off thinking it would help but now that I think about it, that's just gonna make it worse. So you are right about that.

Originally Posted by michael bustamante

if you could post pics that would help immensly. if any parts are needed im sure the guys here or myself have what you need.
also if you wanna get rid of those kegs id be interested

I will try to get pics in the daylight tomorrow. As soon as I get another tank set up I will let you know. Might be a while until I find something. I'm trying to save for a down payment on a house, so I'm want to spend as little as possible until I move out and can start throwing money at this thing.

Originally Posted by hounddogs!

Something else to check would be how freely the accelerator piston moves in the bore. My Buick's AFB acted this way - moving from a 3/4" pump to 11/16" helped immensely. I really think that the apron was just too tight and wouldn't start to move gradually. It was either on or off.

That's something to keep in mind.

Thanks so much for the feedback! Forums like this are so awesome!

[Toms67]

Mine was bouncy to. The shocks were totally shot. I could push them in and out with no effort.

[GASoline71]

Sounds like its just an old truck...

Welcome to the world of 40+ year old rigs.

Gary

[LongBox]

Originally Posted by GASoline71

Sounds like its just an old truck...

Welcome to the world of 40+ year old rigs.

Gary

Great response. You buy a truck this old, you shouldn't expect it to start, run, steer, and brake like a new vehicle. And if it did, you would not have that cool vintage driving experience.

Goes with the huge steering wheel right in your chest, wind up windows, and lousy gas mileage. Great eh!

[Coley]

...it sounds like a blast.
I've got to add a few performance mods and some internal upgrades to get a touchy pedal...lol.
enjoy it.
Coley

[jjzepplin]

That's what I was thinking. Mine is touchy too. Could be the gobs of torque and that low first gear with 4.10's. Tires chirp, people gawk, engine grunts and off I go.

[68C15]

good thing you don't have a Caddy 500 in there.

Are you used to driving old stuff without electric throttle? Serious question. I hate drive-by-wire due to soggy throttle. May just be a learning curve

[kingchris401]

Originally Posted by LongBox

Great response. You buy a truck this old, you shouldn't expect it to start, run, steer, and brake like a new vehicle. And if it did, you would not have that cool vintage driving experience.

Goes with the huge steering wheel right in your chest, wind up windows, and lousy gas mileage. Great eh!

No, I don't expect it to do those things right away. That's why I'm trying to fix it. I bought an old truck because I like the mystery and roughness it comes with. I have an 03 silverado that doesn't need anything and runs great, but that's the thing, it runs great... I still need to be able to drive the 67 though.

Originally Posted by 68C15

good thing you don't have a Caddy 500 in there.

Are you used to driving old stuff without electric throttle? Serious question. I hate drive-by-wire due to soggy throttle. May just be a learning curve

I've driven plenty of carbed things with cables. Can't say the same for rod linkage though. And I guess I don't know what I've driven with drive by wire. I like to stay away from new stuff as much as I can. I'm sure this truck will take some getting used to, but I'd like to be able to take off from a start nice and slow or even drive slowly/cruise around and not launch it one car length at a time in traffic.

[GASoline71]

If the 4 speed is a "granny low" 4 speed. Don't take off in 1st gear (granny). Take off in 2nd and only use 1st if your pulling or hauling. That will alleviate the bucking and short shifting.

The shift knob might even be labeled L-1-2-3-R. At least the knobs in my 1967 and the 1979 I had were labeled that way.

These transmissions should be called 3-speeds with a pulling gear.

Gary

[kingchris401]

Originally Posted by GASoline71

If the 4 speed is a "granny low" 4 speed. Don't take off in 1st gear (granny). Take off in 2nd and only use 1st if your pulling or hauling. That will alleviate the bucking and short shifting.

The shift knob might even be labeled L-1-2-3-R. At least the knobs in my 1967 and the 1979 I had were labeled that way.

These transmissions should be called 3-speeds with a pulling gear.

Gary

That's how mine is. The granny gear is straight up and second is down. I don't start in 1st. That makes it worse... And the PO had a beer tap for a shifter knob. So he just explained where the gears were. The whole shift lever is at shoulder height so it's hard to find the right gear for me since I'm used to normal shifters. But I do know the order they should be in.

[GASoline71]

having an extra long shift lever doesn't help.

Gary

[Coley]

Originally Posted by GASoline71

having an extra long shift lever doesn't help.

Gary

....but it's all the rage right now....lol, 5' long shifter handles scrapping the roof inside the cab.

All Good
Coley

[kingchris401]

Originally Posted by Coley

....but it's all the rage right now....lol, 5' long shifter handles scrapping the roof inside the cab.

All Good
Coley

Ha. Yeah I took the beer tap handle off and put on a grenade I had laying around. Some folks at work said it could have been real at one point too... At least I'll be able to grenade the trans whenever I want!

[kingchris401]

Here's some of the pictures I promised a few days ago.

[jjzepplin]

I cannot see the pics. Just says click for more photo's.

[kingchris401]

Ok, hows that. Don't know what happened before. Also, Is there a way to delete the other post?

[jjzepplin]

I think you have about an hour or so to edit posts.
There is a small kit you can buy to use the larger top hole. Your linkage is too close to the center pivot.
By the way-GM switched to the cable style throttle linkage due to the danger of the engine mounts breaking and the engine moving to the side and then the accelerator would throttle up the engine to full throttle whether you like it or not.
This does not happen with the cable. They made a kit with cables to tether the engine to the frame for a quick fix. It only works with stock exhaust manifolds unless you modify it.
More pics of truck and engine please!

[kingchris401]

Originally Posted by jjzepplin

I think you have about an hour or so to edit posts.
There is a small kit you can buy to use the larger top hole. Your linkage is too close to the center pivot.

More pics of truck and engine please!

Where could I find a kit like that? How would I even go about searching for one?

I'm finding out more and more that this thing is rusted out like crazy...

[jjzepplin]

Probably find one on Summit's website or Holley. A lot of these trucks are real rusted. I see what some of us go thru bringing them back from the dead and I realize I am a lucky man. You may be too. Thing is do you want to fix it or drive it? If you fix it it will most likely be years if ever before it's done. Some of us do it faster but time and money and a place to do it sometimes makes us sell them instead. Sad to see them go on more than one occasion.