Holley 500 conversion?

[1965GMCK1502]

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!

[bigblockv6]

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

[1965GMCK1502]

Originally Posted by bigblockv6

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

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

[LoganKai]

Originally Posted by bigblockv6

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

Have you had any success locating or building headers?

[bigblockv6]

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

[1965GMCK1502]

[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.

[TJ's GMC]

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.

[br-549]

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

[1965GMCK1502]

Originally Posted by TJ's GMC

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.

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

[steve in MI]

Any suggestion on what jets work best?