Carburetor bolts 2 vs. 4

[72K5smoke]

New to site, as well as the K5 world. Finally purchased lifetime dream truck: 72 K5. Learning as I go.
Anybody know why the (orig) carb (#7042104 Rochester 2GV 2bbl) would use gaskets with only 2 bolt holes?

Looks like it could be original, it mounts to (also Orig?) small block chevy engine both of which have 4 bolt holes. Is that part of the fuel leak issue?

Also, only leaks AFTER shutoff......... Bad Float? causing overfill?

just replaced fuel pump, does have new bronze/stone filter w/ additional in-line fuel filter if that makes a diff.

Appreciate any advice.

thanks all.....


B

 

[76zimmer]

sounds like someone put a 2bbl on a 4bbl intake....they made adapters to go either way. GM would have used a 2bbl intake for a 2bbl carb.
Could be bad gaskets in the carb body too, the may not leak when there is a vacuum on the carb.
I assume its a V8....try to find an older model quad...do a rebuild, and run that.

 

[72K5smoke]

SO you're saying the 2bbl carb would've had 2 unused bolt holes and prob be ok?
Maybe it's not the orig intake, huh?

 

[76zimmer]

SO you're saying the 2bbl carb would've had 2 unused bolt holes and prob be ok?
Maybe it's not the orig intake, huh?

Man, I had a brain fart...I was thinking about a 1 bbl from something else. your right on the 4 bolt pattern for the 2bbl. I can't imagine only using 2 bolts on the baseplate.

post up some pics when you can....

 

[diesel4me]

Sorry,the early 70's 307's and some 350's had a 2 barrel,with only 2 bolts,its the
"1-1/4" venturi versions that only had a 2 bolt base for the carb,on the intake..(however the carb HAS 4 bolt HOLES,but only uses TWO!)..
there was a 2GV and 2GC with 1-1/2" bore venturi's that had the 4 bolt carb base & on intake and used a 4 bolt gasket...

I have a 1973 307 in my '81 G-10 van that has the 2 bolt 2 barrel..right now I have a Holley "Economaster" carb that bolted right on,that was originally for a 318 Mopar,and everything fits perfect,even the choke rod to the manifold mounted choke,etc..gets 18 mpg too!..I tired using a Mr.Gasket 2 barrel to 4 barrel adapter on it with a 600 CFM Edelbrock,it drowned it..bogged like crazy and ran way too rich.it has more bals with the tiny 2 bbl carb,it keeps the air velocity going into the intake much faster abd leaner is meaner sometimes..,