305 V6 Carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Alaska_Ryan · 05-09-2010, 04:18 AM

I am doing a top end rebuild on my 1969 305 V6 engine. It lives in a 69 GMC 2500 truck. The engine originally came with a STROMBERG model WW carb and I am unhappy with the performance and reliability.

It has been rebuilt twice, once by me and once professionally and still seems to weep fuel on the outside. It never really leaks, but the outside always seem to be damp with fuel.

Has anyone every done a carb swap to a new, different model of carb? Can you give me suggestions and/or part numbers for the carb itself and adapter plates?

thanks in advance....

292farmer · 05-09-2010, 06:36 PM

sounds like carb icing, mine does it around the base,appears like water but smells slightly of gas, does it smell alot like fuel or just a little? is their a gap under the intake causing it to run cooler? i thought their was a gap on some v6's i know if the intakes aren't warmed properly they can "ice" in vw beetles(tangent) its not common but some unheated intakes to cause carb to freeze and throttle cable to get stuck. i'll take photos of mine when i drive it tomm, see if it looks similar.
btw mines a 292i-6 but sounded similar to carb icing so figured i'd throw it out their. and this site has alot on those motors
http://www.6066gmcguy.org/

292farmer · 05-09-2010, 06:47 PM

found the carb article on that website here ya go
http://www.6066gmcguy.org/holley.htm

**nbrfd007** · 05-09-2010, 09:36 PM

The Holley 500 was a great improvement on my 305 GMC. Well worth it!
Tim

*C-10 simplex* · 05-09-2010, 11:37 PM

1) The other thing is the rochester 2G, supposedly, will bolt in place of the stromberg.

a) maybe there is a way you/we/i can measure the bottom---mounting holes and diameter and position of the throttle blades/barrels and match it to a 2G? Or if you can find one cheap, visually match the bottom.
This way you don't have to mess with an adapter if you went with the holley.

2) This begs the following questions:

a) Why did GMC go with stromberg as opposed to the rochester 2G? It would seem to make better economic sense as the 2G had, by then, been out for 5 model years and proven itself, AND the carburetor was "in house." Unless, at the time, GM owned stromberg?

b) i forgot the 2nd question.

lilred67 · 05-10-2010, 07:25 AM

i just installed a holley 500cfm 2 brl. carb. on my '68 GMC 3/4 ton w/305 v-6. it works great. i also upgraded to the petronix electronic ignition. i have also seen some with a holley 350 cfm carb. i bought the carb,all adapters, and ignition kit from JEG'S for around $350.00. money well spent. i never had alot of luck with the old stromberg WW.

05-09-2010, 04:18 AM	#1
Alaska_Ryan Registered User Join Date: Jul 2008 Location: Delta Junction, Alaska Posts: 7	305 V6 Carb I am doing a top end rebuild on my 1969 305 V6 engine. It lives in a 69 GMC 2500 truck. The engine originally came with a STROMBERG model WW carb and I am unhappy with the performance and reliability. It has been rebuilt twice, once by me and once professionally and still seems to weep fuel on the outside. It never really leaks, but the outside always seem to be damp with fuel. Has anyone every done a carb swap to a new, different model of carb? Can you give me suggestions and/or part numbers for the carb itself and adapter plates? thanks in advance....

05-09-2010, 06:36 PM	#2
292farmer Registered User Join Date: Nov 2009 Location: stoddard nh Posts: 693	Re: 305 V6 Carb sounds like carb icing, mine does it around the base,appears like water but smells slightly of gas, does it smell alot like fuel or just a little? is their a gap under the intake causing it to run cooler? i thought their was a gap on some v6's i know if the intakes aren't warmed properly they can "ice" in vw beetles(tangent) its not common but some unheated intakes to cause carb to freeze and throttle cable to get stuck. i'll take photos of mine when i drive it tomm, see if it looks similar. btw mines a 292i-6 but sounded similar to carb icing so figured i'd throw it out their. and this site has alot on those motors http://www.6066gmcguy.org/ Last edited by 292farmer; 05-09-2010 at 06:38 PM.

05-09-2010, 06:47 PM	#3
292farmer Registered User Join Date: Nov 2009 Location: stoddard nh Posts: 693	Re: 305 V6 Carb found the carb article on that website here ya go http://www.6066gmcguy.org/holley.htm

05-09-2010, 09:36 PM	#4
nbrfd007 Senior Member Join Date: Nov 2007 Location: New Blaine, Arkansas Posts: 751	Re: 305 V6 Carb The Holley 500 was a great improvement on my 305 GMC. Well worth it! Tim

05-09-2010, 11:37 PM	#5
C-10 simplex Account Suspended Join Date: Dec 2008 Location: indisclosed Posts: 1,515	Re: 305 V6 Carb 1) The other thing is the rochester 2G, supposedly, will bolt in place of the stromberg. a) maybe there is a way you/we/i can measure the bottom---mounting holes and diameter and position of the throttle blades/barrels and match it to a 2G? Or if you can find one cheap, visually match the bottom. This way you don't have to mess with an adapter if you went with the holley. 2) This begs the following questions: a) Why did GMC go with stromberg as opposed to the rochester 2G? It would seem to make better economic sense as the 2G had, by then, been out for 5 model years and proven itself, AND the carburetor was "in house." Unless, at the time, GM owned stromberg? b) i forgot the 2nd question.

05-10-2010, 07:25 AM	#6
lilred67 Senior Member Join Date: Mar 2005 Location: weatherford,texas Posts: 1,003	Re: 305 V6 Carb i just installed a holley 500cfm 2 brl. carb. on my '68 GMC 3/4 ton w/305 v-6. it works great. i also upgraded to the petronix electronic ignition. i have also seen some with a holley 350 cfm carb. i bought the carb,all adapters, and ignition kit from JEG'S for around $350.00. money well spent. i never had alot of luck with the old stromberg WW.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.