A freind of mine has a 7040998 carb that was on a parts car he picked up for the 455. The number threw me.
After about 30 min search the web found this page http://bellsouthpwp.net/p/a/padgett46/roch.htm that tells me...

70 - Rochester
4 - 1970's
0 - 1970 - knew that. It was the 998 that was and is bugging me. The page above points me into thinking...
9 - "Emissions" does this mean 49 state? or california?
9 - "Special" what does this mean?
8 - "Auto"

If so, what is difference between this carb and a 7040251. He is Ont Canada, me, in Virginia. Is this a ok core for rebulid? The car "runs" so the carb "works." can an emissions carb be converts to normal? I would hate to ship it to me to find out it is junk. any thoughts or ideas are welcome. Thanks.

Adam

 

I'm guessing that the "emissions" designation has something to do with the bowl vent. 1970 was the first year for evaporative emissions systems, primarily in California. This system needs a closed bowl vent to operate properly. Normal carbs vent the bowl into the air horn.

 

Is your friend looking at the numbers cast on the carb or the numbers stamped on the side?
The stamped numbers are the ones you need to I.D. it.

According to the Buick guys it could be for a '70 Stage 1.
If it is that carb there are some differences between that and a regular Q-jet according to the buhoggers.
Check with the carb rebuilder and find out if it can be used or is worth rebuilding if it has special parts that are big bucks or unobtainable or something. I would see what a Buick guy would pay for it if it's something special, could be lucrative if it's rare and pay for another carb and rebuild, you never know.


http://www.v8buick.com/showthread.php?p=1550791

 

the emissions designator denoted california or federal(49 state) certification. generally the third from the last was a 2 for federal or a 5 for california emissions. a.i.r. cars had 703 as the first 3 digits for 1966 and 1967. there were exceptions to this too. 8 or 9 in the third from the last digit also meant special applications, ie. marine/irrigation engines. there is a general rule of thumb with rochester numbering, but never a "set in stone" rule.


bill

 

Could this carb still be good usable core for the street with a typical rebiulding? Since it was on a street car I hope so. Thanks

Adam

 

it should be useful in rebuilding, but i'm still questioning the carb. model number given.


bill

 

Yeah, I think my friend had one to many. I have also been talking to Greg at Sparky's Carbs. I am thinking, as BVista thought, my friend is looking at the casting numbers and not the stamping (he also is going edlebrock on the engine I will let every one when/if I can get to the bottom of this. Thanks

Adam