[JoeF]

Black 65,
I assume when you say "less ignition lead" you mean less advance. Roughly, what should my curve look like? Most of the info I've seen here says 12 initial 34-36 total all in by 3000.

[Black 65 GTO]

Joe,

There are many variables involved when dealing with both the total amount and rate of advance.

These variables are:

Cylinder Head Design
Type of piston
Type of fuel used
Air/Fuel Ratio
Weight of Vehicle
Rear Gear Ratio
Converter Stall Speed

So, you can see that one set of numbers would not work for any combination.

You can either find the total amount of timing that is ideal by running timing loops on either a dyno or at the drag strip. This involves starting at low, say 30 degrees total timing, and increasing advance by two degrees unitil you reach a maximum power (dyno) or MPH at the dragstrip.

Your timing curve involves much more tuning. This will depend on a lot of the examples above as well as if you intend to drive the car mostly on the street. Also include the vacuum advance as part of your distributor tuning. This makes a world of difference in the drivability!

If you are not willing to invest the amount of time required to acheive the best curve (this can take many hours), I would suggest that you send your distributor to a reputable person to have the curve modified to your intended use and car.

As a matter of fact, there are a few guys on this board that specialize in this service.

[img]http://groups.msn.com/_Secure/0PAAAABsTshS*JL3aL9Lt3DTWpiaZQYuTwADv04vUiCSGPh1UW kUzJcyoBHF!u5vkOCDRCP1bN46o1zkzqk3S2WcjuGbw2xV8/Black-65-2-1.JPG[/img]

[JoeF]

Black 65,
Thanks for the info. My car will see almost exclusive street driving. Curiosity on what it will do might get me to the track one night, but those trips will be few. Basically I'm looking to make improvements while staying very close to stock (at least in appearance). Not looking to squeeze every last pony out of each component. Having someone knowledgable modify my curve sounds about what I'm looking for. I've figured out who the engine builders and carb guys on the board are, who are the "sparky's" that do recurves?

[Rockcrusher-M22]

Definitely don't get rid of the heads because of the chamber size... Just match up the rest of the engine so the heads can be utilized. I had a set of 670's from my 67 GTO sent to Warrior Racing in Michigan. I spent $1100.00 and had them ported, bronze guides, cut for teflon seals, new valves and assembly. When I got them back they brought a tear to my eye. They were gorgeous and not to mention they KICKED A$$ compared to the #12 RA III I was using. I was able to run these heads with 10.75 CR in a .030 400 zero decked with no pinging on Sunoco 94 octane. As for the chamber, they were pretty much untouched. Only the ports were done. There have been articles written that say the 670 are one of the best overall performance heads Pontiac ever put out.

[goatseeker]

JoeF,
With regard to distributor recurving - have you considered an HEI? I'm going to use a small body HEI distributor conversion from Daves Small Body HEI (www.davessmallbodyhei) on my 462. Check out the pictures and info on his website. For what you would spend on a Mallory or MSD unit you can have yours (or any rebuildable core) converted with custom recurving in a totally stock-appearing, "stealth" distributor.
Just an option to consider.

http://kurtspontiac.homestead.com/TimSimpson66GTO.html

[JoeF]

Goatseeker,
Funny you mention HEI. I have an HEI in the car now. What I'm thinking of is switching to a points style distributor with either a Pertronix or small HEI (stock look). Since I don't have a core, I was trying to find a "distributor guy" who might have one that I could buy with the appropriate curve work and rebuild already done. I'd then drop in a Pertronix and be all set.