1968 427 quadrajet choke linkage

[Dale C.]

Re: 1968 427 quadrajet choke linkage

John, I guess I'm in the hunt for the linkage now. I think your box will show up before that darn linkage. Where did you find it? I'll keep my eye out for your box. Dale

[John B.]

Re: 1968 427 quadrajet choke linkage

Joe, thank you for looking up the part numbers. I now know what I need. I'll probably try to modify the one I have to work until I can find a better one.

Dale, the linkage showed up on EBay. The gentleman who listed it has been buying and selling carbs/parts for many years. His business is Specialized Investments O.E.M. Carburetors and his name is Mark Smith. Talked to him about some additional parts I might need. Nice guy to talk to. Doubt that he has another linkage, but you never know. I'll keep on the lookout for the linkage for you as well. I did speak with a person at Fall Carlisle who says that he has a complete 7028209 carb with the correct linkage on it, but he will only sell it completely restored and wants a lot for it. If you are interested let me know and I'll try to find his contact info.

Ed, I agree, the drawing does as much to confuse the situation as anything. I am at this point relatively certain that how I have the linkage configured, rod to the outside and coil connection forward, as seen in the pictures in my original post is the correct orientation. Lars confirmed that it was installed/assembled correctly when he looked at my pictures. The square hole in the top of the cover needs to be in the forward outside corner of the top of the cover, just as the cover is on Dale's car. Thanks for talking a look through your parts for me.

Thanks for all the help with this quest. Now on to the next 68 only mystery.

John

[Dale C.]

Re: 1968 427 quadrajet choke linkage

IMG_7158.jpgJohn, Here is a better picture of the cover. Could you PM me your contact info? I would like to discuss our need for parts and I am not very savvy at using this forum. Thanks, Dale

[Edward B.]

Re: 1968 427 quadrajet choke linkage

It gets even MORE confusing! Doc Rebuild lists a NOS coil spring (thermostat) for 66-67 327 or 427 & 68-69 427 as his P/N 3752103 (PAGE 83, item "Q" in his current catalog). This is shows as being a "pull down" style of coil. However, he also shows another NOS coil (item "R" directly under it - his P/N 3752104) which is a "push up" style coil as being correct for 68 327 or 427 & 69 427/390. You don't suppose there was a change during the 1968 model year do you? I checked the latest TIM&JG (5th edition, page 60), but it doesn't have much info regarding the choke stove, so I'm only spitballing here. I base this mostly on the above and the AIM. If you look at UPC 6, sheet C1, item 10, there's a note (1) that states "6-27-67 was 3903312". This would seem to indicate a change made sometime during the 1968 model year. We all know we can't go by the date in the AIM since that was just the date was made to the drawing, and the actual change could be up to a few months before or after that date, so it's theoretically possible early cars go the 67 Holley "pull down" style and later cars go the Rochester "push up" style.

The L36 section in the AIM doesn't help since it says "assembles the same as production", so more investigation would be necessary.

Ed

[Dale C.]

Re: 1968 427 quadrajet choke linkage

Then from what Joe says "that the 68 BB cover was replaced with the correct one for the 69" why was the 68 billed as a one year only and was so different??? 68 must have been almost the same as 69 in operation as the orientation had to be the same if the cover was compatible. It all must revolve on the push up or pull down of the coil spring and what side of the pivot, fulcrum, the rod attached to. Dale

[Edward B.]

Re: 1968 427 quadrajet choke linkage

I agree Dale. Either "pull down" or "push up", and the chole coil oriented toward the rear of the car or the front. I'd like to see if anyone with an VERY early 68 L36 could weigh in on this. I'd like to see what they have.

Ed

[Cecil L.]

Re: 1968 427 quadrajet choke linkage

There were several TSB's on the choke linkage in this time frame as I recall.

[Dale C.]

Re: 1968 427 quadrajet choke linkage

There is one in the new JM 68 T-23 and it covers just changing the actual choke rod to alleviate some binding problem, it changed the offset and reversed the linkup side to the bracket. That darn bracket is the confusing issue. Dale

[Terry B.]

Re: 1968 427 quadrajet choke linkage

Ed,

Here is a couple of pictures of my '68 L36 set up. My car is a Dec '67 build however it has been restored. It is an automatic which made my search for the correct carb a bit more difficult. I hope this helps.
Terry1968-Carb-choke.jpg1968-Carb.jpg

[Dale C.]

Re: 1968 427 quadrajet choke linkage

Terry, Very interesting in that yours is yet another example of the outboard most bracket (octopus). Every drawing or figure I have seen is different and all of the pictures are different. Some are similar but different. Look at the Rochester bracket # RP3588 in Johns 1st picture. I call it the octopus bracket in that it looks like an octopus head with the tentacles at the other end. On that octopus bracket the rod attaches to the forward position of the pivot point, on octopus right tentacle, whereas my type connects to the aft of the pivot point. Look at the different positions of the tentacles in the pictures, yours and Johns, above. Then compare those to the 427-390 figure in 2C in my service manual picture. Which is correct? Then how that rod attached to the thermo coil on the manifold makes a big difference. Terry, can't see how the coils are positioned but it looks like ours are the same and with same cover yet plumbed to different sides of pivot arm. Dale

[Dale C.]

Re: 1968 427 quadrajet choke linkage

Here is an old carb, GM rebuilt, from Ebay at a bad angle but looks to be like Johns 1st picture.68 Carb 7.jpg

[Cecil L.]

Re: 1968 427 quadrajet choke linkage

Not specific to 68, but a little history is usually good at helping to understand how we got here.

First is a TSB from 66 with good illustrations of the different choke versions.

[Cecil L.]

Re: 1968 427 quadrajet choke linkage

And some info from 67.

According to the 1968 New Product Information booklet, the 68 quadrajet was a carryover from 67.

[Wayne M.]

Re: 1968 427 quadrajet choke linkage

There is one in the new JM 68 T-23 and it covers just changing the actual choke rod to alleviate some binding problem, it changed the offset and reversed the linkup side to the bracket. That darn bracket is the confusing issue. Dale

Dale -- is the Dealer Service bulletin you refer to (68-T-23) the Re-Issue version dated April 24th 1968 ? I see that for the L36 it calls for choke rod #3937738. Described as having a greater off-set and a reverse entry direction at the choke lever end. Drawing shown for early and late versions of the rod for L36 as well as the tri-powers.

[Dale C.]

Re: 1968 427 quadrajet choke linkage

Wayne, Yes it is and it's in the new JM. Thanks Cecil, I'll look that over and get more confused. Dale