I6 to V8 Conversion: Throttle Linkage? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Stepsides 4Ever · 03-16-2004, 05:50 PM

We are in the process of converting our '70 Chevy 1/2T short step from the 6 cyl./3-speed to a 350/700R4 setup and I'm pretty sure that I'm going to have to do something with the stock throttle linkage. Do I need to convert it to the later model cable-style connection? There are plenty of them at our local pick-a-part yards...

Any suggestions?

Thanks to all of you guys! This board is the BEST!

dubie · 03-16-2004, 06:01 PM

you should just need the throttle linkage out of a 67-72 factory V 8 truck for it to work properly

Stepsides 4Ever · 03-16-2004, 06:04 PM

Unfortunately, due to the popularity of these years, there's a scarcity of those in my area (So. Cal.), and the prices for NOS parts reflects that.

dubie · 03-16-2004, 06:17 PM

there are members on this board that will for sure have one for sale. Just ask on the parts board, you just might get lucky and find one close to you. Lots of California members here

bigskiohio · 03-20-2004, 10:32 PM

use later cable just use die grinder to make square openining in firewall

Stepsides 4Ever · 03-20-2004, 10:54 PM

Later cable, as in '73-'87? Or as in '71-'72?

The local pick-a-part is full of the '73-'87 stuff.

jjk3 · 03-20-2004, 11:36 PM

I managed to make mine work when I went to my 250 from 327. I don't know how, but I had 2 trucks to work with. I would take a look at the '73-'87 setups and see what it would involve to swap over. If there are alot of them, prices should be pretty cheap. Swapping shouldn't be a big deal at all. I'm going to have to do it soon when I put my 4 barrel on the 250. John

Stepsides 4Ever · 03-21-2004, 12:26 AM

A four-barrel on a 250? Now that will be interesting!!!

Quote:

Swapping shouldn't be a big deal at all.

That is exactly what I was thinking! I expected to hear someone say that they tried it and it wouldn't work because of....but no one seems to be saying that, and you did it, so it is do-able!

My belief is that anything will go into anything if you have enough time and enough money and, most importantly, the desire to do it. I want to do this, but I have so many other things that have to be done that I don't want to devote a lot of time to this one aspect, but if it is not a major task, then I'll tackle it. It is too tempting not to...

BLACK AND BLUE 67-72 · 03-21-2004, 02:18 AM

I modified a 63 I6's linkage to work on my buddy's 69 with a 350, his original wouldn't work after we changed the intake and carb to an Edelbrock. It works great with the I6 linkage.

Stepsides 4Ever · 03-21-2004, 02:31 AM

Yup, everything on the I6 that I won't be able to use on the conversion will be up for sale for a reasonable price...not to make a profit, but to help defray the cost of the conversion, and to keep as many of these vehicles on the road as possible. I admire your pluck (and wisdom, in this age of $2+ per gallon of gasoline) in sticking with the 6-cyl.

Rod · 03-21-2004, 03:18 PM

You can put a 4 bbl on a six cylinder... takes the correct type intake manifold though... here a pic someone posted at one time.

Tx Firefighter · 03-21-2004, 05:49 PM

Everyone seems to make a big deal out of the throttle rod.

There is a lever sticking out of the firewall that is hooked to the pedal inside the truck. Put a block of wood or something similar under the pedal inside the truck to hold it up off of the floor a ways. Next, take a tape measure and measure the distance between the rod and the hole in the carburetor linkage. Now, build a connecting rod that's the right length. Now, you're done.

I always use threaded rod and these...

.

Total cost is under 10 bucks for the whole deal and it takes about 15 minutes. Then, you can say you have a high tech throttle linkage. Make sure and adjust the threaded rod length so the pedal hits the floor when the carburetor hits WOT, so you don't stress out the carburetor linkage arm by trying to torque it over too far.

The picture below is my 6 cylinder truck throttle rod before I swapped it over to the longer one for the V8. All you are doing is making a longer connecting rod. You could easily use the 6 cylinder one and lengthen it a few inches with plain 1/4 inch rod available for about a buck at Home Depot. Use a hack saw and welder to splice it longer and weld it together.

jjk3 · 03-21-2004, 08:09 PM

Stepsides 4Ever-- I had the 250 laying around with only 12k on it, and my 327 was running on 5 cylinders. I really like the straight six though, it's different. Anyway I'm going to run an Offy intake just like Rod posted. One of the moderators on www.inliners.org is running 3 (yes 3) four barrels on his 250. That's his engine in my sig. Very cool stuff.

What Tx Firefighter posted is right on the money. I'm pretty sure all I did was have to adjust the length, and mess with the brackets a little. Easier than trying to go to junk yards and stuff. Good luck. John

stickshift_or_walk · 02-07-2005, 12:41 PM

Guys,

Tx's solution looks typically slick, but I'm still working out the details. The donor quadrajet has a post sticking out of the carb linkage arm, which doesn't mate to the post on the carb end on the 6cyl rod.

No problem extending the rod, but I'd like to see someone's solution for mating the rod to the Q-jet arm...

Thanks...SSOW

**CPNE** · 02-07-2005, 12:53 PM

Quote:

Originally Posted by stickshift_or_walk

Guys,

Tx's solution looks typically slick, but I'm still working out the details. The donor quadrajet has a post sticking out of the carb linkage arm, which doesn't mate to the post on the carb end on the 6cyl rod.

No problem extending the rod, but I'd like to see someone's solution for mating the rod to the Q-jet arm...

Thanks...SSOW

If you're talking about a ball-shaped stud on your qjet that is intended to be used with the cable (not rod) linkage, then all the ones I've seen are threaded and have a 1/4 inch nut on the back side to attach it to the qjet's throttle bracket. Removing that stud will leave a hole for the rod bracket to pass thru. Shim with some washers and use a cotter pin and you should be good to go. This assumes your rod has a 90 degree bend on the end with a small hole thru it for a cotter pin like the stok rods have.

stickshift_or_walk · 02-08-2005, 12:52 PM

Thanks, Jeff - that's the setup I've dealt with before, too. Not this time, though. This pic should get us on the same page.

The post on the arm is for a cable linkage, as the carb came from a mid-80's donor. It is swedged in to the arm, so I can probably grind the back off and pull the post out, leaving a hole as you describe. However, the hole will be larger than the 6-cyl linkage post, so I'd need to take up the slop somehow.

Another way to go, maybe better, would be to find one of these ball joint thingys that will mate to the fine threads on the end of the rod.

That way, I can put the threaded end through the larger hole tighten it to kill the slop. Thoughts or better ideas, anyone?

Thanks...SSOW

03-16-2004, 05:50 PM	#1
Stepsides 4Ever Stepsides Are Bedder Join Date: Feb 2004 Location: Norco, CA Posts: 238	I6 to V8 Conversion: Throttle Linkage? We are in the process of converting our '70 Chevy 1/2T short step from the 6 cyl./3-speed to a 350/700R4 setup and I'm pretty sure that I'm going to have to do something with the stock throttle linkage. Do I need to convert it to the later model cable-style connection? There are plenty of them at our local pick-a-part yards... Any suggestions? Thanks to all of you guys! This board is the BEST!

03-16-2004, 06:01 PM	#2
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	you should just need the throttle linkage out of a 67-72 factory V 8 truck for it to work properly __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

03-16-2004, 06:17 PM	#4
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	there are members on this board that will for sure have one for sale. Just ask on the parts board, you just might get lucky and find one close to you. Lots of California members here __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

03-20-2004, 10:54 PM	#6
Stepsides 4Ever Stepsides Are Bedder Join Date: Feb 2004 Location: Norco, CA Posts: 238	Later Cable? Later cable, as in '73-'87? Or as in '71-'72? The local pick-a-part is full of the '73-'87 stuff.

03-20-2004, 11:36 PM	#7
jjk3 It's just a check engine lamp. Join Date: Apr 2001 Location: Melbourne, FL Posts: 311	I managed to make mine work when I went to my 250 from 327. I don't know how, but I had 2 trucks to work with. I would take a look at the '73-'87 setups and see what it would involve to swap over. If there are alot of them, prices should be pretty cheap. Swapping shouldn't be a big deal at all. I'm going to have to do it soon when I put my 4 barrel on the 250. John __________________ Active Inliner---bigchevy66 68 SWB Stepside 250 L6/3 on the floor/ Hedman headers, HEI, MSD 6A box, K&N filter, Offy intake and Edelbrock 600cfm 4 barrel Soon to have: WC T-5 five speed 66 SWB Stepside-undergoing restoration

03-16-2004, 06:04 PM	#3
Stepsides 4Ever Stepsides Are Bedder Join Date: Feb 2004 Location: Norco, CA Posts: 238	Unfortunately, due to the popularity of these years, there's a scarcity of those in my area (So. Cal.), and the prices for NOS parts reflects that.

03-20-2004, 10:32 PM	#5
bigskiohio Registered User Join Date: Sep 2003 Location: Ohio Posts: 127	use later cable just use die grinder to make square openining in firewall

03-21-2004, 02:18 AM	#9
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	I modified a 63 I6's linkage to work on my buddy's 69 with a 350, his original wouldn't work after we changed the intake and carb to an Edelbrock. It works great with the I6 linkage. __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

03-21-2004, 02:31 AM	#10
Stepsides 4Ever Stepsides Are Bedder Join Date: Feb 2004 Location: Norco, CA Posts: 238	Zoomy... Yup, everything on the I6 that I won't be able to use on the conversion will be up for sale for a reasonable price...not to make a profit, but to help defray the cost of the conversion, and to keep as many of these vehicles on the road as possible. I admire your pluck (and wisdom, in this age of $2+ per gallon of gasoline) in sticking with the 6-cyl.

03-21-2004, 03:18 PM	#11
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	You can put a 4 bbl on a six cylinder... takes the correct type intake manifold though... here a pic someone posted at one time. Attached Images __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

03-21-2004, 05:49 PM	#12
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Everyone seems to make a big deal out of the throttle rod. There is a lever sticking out of the firewall that is hooked to the pedal inside the truck. Put a block of wood or something similar under the pedal inside the truck to hold it up off of the floor a ways. Next, take a tape measure and measure the distance between the rod and the hole in the carburetor linkage. Now, build a connecting rod that's the right length. Now, you're done. I always use threaded rod and these... . Total cost is under 10 bucks for the whole deal and it takes about 15 minutes. Then, you can say you have a high tech throttle linkage. Make sure and adjust the threaded rod length so the pedal hits the floor when the carburetor hits WOT, so you don't stress out the carburetor linkage arm by trying to torque it over too far. The picture below is my 6 cylinder truck throttle rod before I swapped it over to the longer one for the V8. All you are doing is making a longer connecting rod. You could easily use the 6 cylinder one and lengthen it a few inches with plain 1/4 inch rod available for about a buck at Home Depot. Use a hack saw and welder to splice it longer and weld it together. __________________ I'm on the Instagram- @Gearhead_Kevin

03-21-2004, 08:09 PM	#13
jjk3 It's just a check engine lamp. Join Date: Apr 2001 Location: Melbourne, FL Posts: 311	Stepsides 4Ever-- I had the 250 laying around with only 12k on it, and my 327 was running on 5 cylinders. I really like the straight six though, it's different. Anyway I'm going to run an Offy intake just like Rod posted. One of the moderators on www.inliners.org is running 3 (yes 3) four barrels on his 250. That's his engine in my sig. Very cool stuff. What Tx Firefighter posted is right on the money. I'm pretty sure all I did was have to adjust the length, and mess with the brackets a little. Easier than trying to go to junk yards and stuff. Good luck. John __________________ Active Inliner---bigchevy66 68 SWB Stepside 250 L6/3 on the floor/ Hedman headers, HEI, MSD 6A box, K&N filter, Offy intake and Edelbrock 600cfm 4 barrel Soon to have: WC T-5 five speed 66 SWB Stepside-undergoing restoration

02-07-2005, 12:41 PM	#14
stickshift_or_walk Left Foot Functioning Join Date: May 2004 Location: Duncan, OK Posts: 350	Guys, Tx's solution looks typically slick, but I'm still working out the details. The donor quadrajet has a post sticking out of the carb linkage arm, which doesn't mate to the post on the carb end on the 6cyl rod. No problem extending the rod, but I'd like to see someone's solution for mating the rod to the Q-jet arm... Thanks...SSOW __________________ 69 C10 (#1 son's ride) 72 C20 (Dad's farm truck) 82 K30 (Ex - brush pumper project)

02-08-2005, 12:52 PM	#16
stickshift_or_walk Left Foot Functioning Join Date: May 2004 Location: Duncan, OK Posts: 350	Thanks, Jeff - that's the setup I've dealt with before, too. Not this time, though. This pic should get us on the same page. The post on the arm is for a cable linkage, as the carb came from a mid-80's donor. It is swedged in to the arm, so I can probably grind the back off and pull the post out, leaving a hole as you describe. However, the hole will be larger than the 6-cyl linkage post, so I'd need to take up the slop somehow. Another way to go, maybe better, would be to find one of these ball joint thingys that will mate to the fine threads on the end of the rod. That way, I can put the threaded end through the larger hole tighten it to kill the slop. Thoughts or better ideas, anyone? Thanks...SSOW __________________ 69 C10 (#1 son's ride) 72 C20 (Dad's farm truck) 82 K30 (Ex - brush pumper project)

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