EGR TVS for 78

[Mike M.]

OK, With much help from BaryK and Bobs78, I'm quite a bit closer, but still not quite there. Every indication (Manual and photos) shows the EGR TVS top connection hosed to the EGR valve, and the bottom connection hosed to the carb. Simply put, my Rochester QJet carb does not have a connection for this that I can find. All of my carb connections seem to be intact and correct. Anyone have any clues?

 

[BarryK]

you sure you still have the correct stock carb on there and not another model replacement Q-Jet?

 

[Mike M.]

yes, it's actually has embossed Rochester Quadra-jet on it, but is also has a sticker that has 'holley rebuilt' on it? I did actually find a capped hose connection on the carb that I did connect the other side of the EGR TVS to, just to try it out. As you face the front of the carb, this hose connection is all the way to the right (driver's side). However, now the exhaust seems to sputter every few seconds.

 

[bobs78]

Mike, maybe its just not the right model Q-Jet for your car.!?

Here's a link in the CAC Model Center that lists the Q-Jet model numbers for '78s...
http://corvetteactioncenter.com/specs/c3/1978/78id.html

 

[BarryK]

Mike, maybe its just not the right model Q-Jet for your car.!?

Here's a link in the CAC Model Center that lists the Q-Jet model numbers for '78s...
http://corvetteactioncenter.com/specs/c3/1978/78id.html

yep, that's what I'm saying........ it may be a Q-Jet but not the correct model Q-Jet.

 

[Mike M.]

Guys, I think you're right. The number is Rochester # 7045213, then a sticker that has 'Holley Rebuilt 64-7153'. These carb numbers don't show up on any compatibility lists of '78 Corvettes. Now I'm curious if any of my carb hose connections are correct.

 

[bobs78]

Bad news Mike...

7045213 CHEV & GMC Truck 75-76 non-emissions

7045213 YA
101 5

70 = Rochester products division#
45 = Production year, 4=1970's, 5=specific year, 1975
2 = Carb ID, 2=49 state Q-jet
1 = Division, 1=Chevrolet products
3 = Tranny ID*, Even number=Automatic, Odd number=manual
101 5 = Julian Date Code, Friday April 11 1975
YA = Engine assembly plant

# Carbs starting with 70xxxxx are pre-1976. Carbs starting with 170xxxxx are 1976 onwards.
* tranny ID is not cast in stone.

 

[Mike M.]

Bob and Barry, I think we've nailed it. We had also found the part number breakdown of the Carb as Bob posted above, and concluded that we had an incompatible carb. So now - to replace or to keep the carb ?! What would you guys do? Any performance considerations?

 

[BarryK]

Mike

you don't have too many options as I see it.

1. replace the carb for a more correct model that offers the vacuum ports you require for all your hose connections.

or

2. remove some of the emissions equipment off the car and not worry about all those extra hoses and crap.