7040204

[D S.]

A friend purchased a rebuilt/restored 7040204 Quadrajet for his 1970 LS-5. He began to get curious that the throttle linkage did not look correct when he temporarily mounted it on his fresh rebuilt engine. Part of it strikes the fourth intake manifold bolt. Could it be that the carburetor rebuilder installed a small block linkage?


QJet linkage.jpg

Thanks,
Scott Sims
Texas Chapter

[David L.]

Re: 7040204

Scott,

I have several 7040202 (for A.T.) and 7040203 (for M.T.) Roch. 4bbl. carbs. I can take a few photos of the linkage part of them sometime tomorrow for comparison.

Dave

[Patrick H.]

Re: 7040204

I don't see that you have a base basket between the carb and the intake. If so, it's not obvious. That would raise the carb the amount you need.

[D S.]

Re: 7040204

Scott,

I have several 7040202 (for A.T.) and 7040203 (for M.T.) Roch. 4bbl. carbs. I can take a few photos of the linkage part of them sometime tomorrow for comparison.

Dave

Thanks, David. I would appreciate that. Original 204s would help, too.

[D S.]

Re: 7040204

I don't see that you have a base basket between the carb and the intake. If so, it's not obvious. That would raise the carb the amount you need.

Patrick,
What the heck is a base basket? And what is that cylindrical object between the linkage and the carburetor?
It appears on my friend's carburetor that when the spring is properly attached it will pull that part up and clear the bolt. But the linkage looks nothing like my '70 LS-5's. Or any others I have seen.

Thanks,
Scott

[Patrick H.]

Re: 7040204

Gasket that goes between the carb base and the intake crappy photo - the good ones are much thicker)

The other thing is a 70-only part. Picture in previous post is from a car at Bloomingotn last year.




Addendum - here is an example from Napa:

https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=FPG60111_0158547655&An=599001+101970+50012+2012030

[D S.]

Re: 7040204

Gasket that goes between the carb base and the intake crappy photo - the good ones are much thicker)

The other thing is a 70-only part. Picture in previous post is from a car at Bloomingotn last year.

Oh. I have the gasket but I'm sure the guy who is having linkage issues hasn't got his on yet.
I don't have that '70-only thing on my 204 and I don't recall seeing it on many 1970 LS-5s although most have their air cleaners on. What is it and what is it supposed to do?

[David L.]

Re: 7040204

Scott,
I could not find my 7040202 carbs (70 300 HP w/A.T.) but I did find two of 7040203 carbs (70 300 HP w/M.T.) and one 7040208 carb (70 truck w/A.T.).
Pictured from left to right are the following:
1. "7040203", "DB", and "2619" (261st day of 1969) with "RP 37248" stamped on linkage.
2. "7040203", "A0" (Jan. 1970), and "DB" with "RP 365??" stamped on linkage (drilled hole through last 2 digits).
3. "7040208", "IA", and "0830" (83rd day of 1970" with "RP 37248" stamped on linkage.
All 3 linkages appear to be the same in shape.

Dave

[D S.]

Re: 7040204

Scott,
I could not find my 7040202 carbs (70 300 HP w/A.T.) but I did find two of 7040203 carbs (70 300 HP w/M.T,) and one 7040208 carb (70 truck).
Pictured from left to right are the following:
1. "7040203", "DB", and "2619" (261st day of 1969) with "RP 37428" stamped on linkage.
2. "7040203", "A0" (Jan. 1970), and "DB" with "RP 365??" stamped on linkage (drilled hole through last 2 digits).
3. "7040208", "IA", and "0800" (8th day of 1970" with "RP 37248" stamped on linkage.

Dave

They appear to be basically all the same and similar to my friend's 204 yet my 204 is different than yours and his. Can these be changed out without having to dismantle the carburetor?

[Patrick H.]

Re: 7040204

They appear to be basically all the same and similar to my friend's 204 yet my 204 is different than yours and his. Can these be changed out without having to dismantle the carburetor?

No.

The one on the carb in your first post looks more like one from a truck. That is probably the issue - had one like that too and had to swap it out. NOT fun as the base plate has to be removed, the screws ground down and throttle plates removed, then the process reversed.

I ended up swapping base plates from another carb as it was a lot easier.

Patrick

[Patrick H.]

Re: 7040204

Oh. I have the gasket but I'm sure the guy who is having linkage issues hasn't got his on yet.
I don't have that '70-only thing on my 204 and I don't recall seeing it on many 1970 LS-5s although most have their air cleaners on. What is it and what is it supposed to do?

I "think" it was supposed to ease down the throttle when you let off. My 70 Cutlass has one too.

Patrick

[D S.]

Re: 7040204

Thanks, Patrick. He's gonna be "thrilled" to know that as he says he paid $400 for the 204.

[David L.]

Re: 7040204

Scott,

According to information in my Delco Rochester catalog (Dec. 1969) the 7040204 uses base (called "Throttle Body Assembly") # 7041303 (part # 70 in drawing).

The 7040202, 7040203, and 7040213 use base 7036841.
The 7040208 uses base 7036919.

Dave

[Joe L.]

Re: 7040204

Gasket that goes between the carb base and the intake crappy photo - the good ones are much thicker)

The other thing is a 70-only part. Picture in previous post is from a car at Bloomingotn last year.




Addendum - here is an example from Napa:
https://www.napaonline.com/Catalog/C...+50012+2012030

Patrick and Scott------


The GM #3967470 gasket is a bit thicker than the one shown but likely not enough thicker to raise this carburetor enough for the lever to clear.

In this case, I think that this carburetor has been at some point fitted with a carburetor throttle body assembly that's not correct for this carburetor part number. As with most other commercially rebuilt parts, the numbers on the carb may mean nothing. A rebuilder may "mix-and-match" parts to build up whatever carburetor they wish.

As far as the "cylindrical object" goes, if Scott's speaking of the device seen to the left of the carburetor and attached to the right side of the intake manifold, that is the transmission controlled spark (TCS) solenoid. It interrupts vacuum advance under certain engine operating conditions.

[Patrick H.]

Re: 7040204

Thanks, Patrick. He's gonna be "thrilled" to know that as he says he paid $400 for the 204.

The top portion is probably a 204. As Joe L notes, it's the base plate and accessories that come from elsewhere. Not tough to find a correct base plate with correct throttle arm and have them redone. Most passenger car ones will be correct - just check eBay for a cheap used one or pick one up at a swap meet.

Patrick