Holley 500 conversion?
 

Hi All, was hoping to get some real life pros and cons of the 500. Current setup is the 305v6 with a Rochester 2G that’s working fine, especially after swapping in new Taylor wires and platinum plugs.....But always looking for a little more performance for the engine. I’ve heard nothing but great things about the Holley swap...but curious if anyone has had any negative outcomes?
Positive outcome info also very appreciated.
Thanks in advance!

Re: Holley 500 conversion?
 

The Holley 500 will really wake up the 305 V6 though at times some 305's may run too rich and be a little over carbureted so a simple rejetting is all that's needed. To enhance this carburetor conversion I suggest a good flowing dual exhaust and an upgrade to electronic ignition:ok:

Re: Holley 500 conversion?
 

Thanks, Peter. The HEI is in, and 2 1/4” dual exhaust going in next week. Holley carb on the way.

Re: Holley 500 conversion?
 

Have you had any success locating or building headers?

Re: Holley 500 conversion?
 

I have not tried headers, though there are freer flowing manifolds used on bigger truck engines.

Re: Holley 500 conversion?
 

[QUOTE=LoganKai;69353]Have you had any success locating or building headers

The headers are a major headache....there was some discussion about using Pontiac three-ports but they don’t match up and require customization. Haven’t tried....very happy with just the dual exhaust though.

Re: Holley 500 conversion?
 

Dual exhaust with the stock manifolds will do the job just fine for ya. Headers would have to be custom made and the results would not be worth the effort(or money!) unless more work was done to the engine. The mentioned mods will make for a nice increase in power....and change the exhaust tone. :thumbsup:

Re: Holley 500 conversion?
 

I also have interest in swapping to a Holley but i have a 401. Anyone have an adapter or a "fix"? Thanks! ja

Re: Holley 500 conversion?
 

Finally got around to doing the Holley swap and very happy with the results.

Re: Holley 500 conversion?
 

Any suggestion on what jets work best?

Re: Holley 500 conversion?
 

From the Archives section; I jetted down as well to 68's and liked it.

Re: Holley 500 conversion?
 

No mods necessary. I used the stock jets that came with the Holley

Re: Holley 500 conversion?
 

Does the 2G bolt right on to the intake with the same bolt pattern or is a conversion plate needed? I have a rebuilt 2G from a 283 and would like to try if it's an easy swap.. Just want to get this truck running good, nothing fancy or high performance.

Re: Holley 500 conversion?
 

Yes it should bolt right up if it’s the 2G with the close bolt pattern.

Re: Holley 500 conversion?
 

I've seen quite a few 305 V6's with the Rochester 2G used to replace the stock WW carb. It is said that GMC actually used some 2G carbs on the 305 V6 in 1967 because there was a shortage of Bendix/Stromberg carburetors since Chrysler also used these carburetors in large numbers on their 318 engines.

Re: Holley 500 conversion?
 

Great, thanks for responding. It's the smaller base.. Stock air cleaner fits the top hole.. 2 3/8 or so.