Help me complete my tuning.

[Internexus]

Have a 65 stang with a 289, stock 2 barrel, full exhaust and an electric fan, c4 auto and otherwise pretty basic.

I run 87 octane, have timing set to about 8* advance, the air/fuel adjustment screws on the carb are both about 1.5 turns out (rich) and the car idling at about 1,000rpm.

Still adjusting the electric choke to operate appropriately in the morning but otherwise, I am trying to figure out if I have everything dialed in correctly here. The car doesn't feel all that fast but sadly that's my own fault because of the other vehicles I am used to driving and not really familiar enough with carb'd vehicles.

Anyone have any thoughts on this or perhaps some recommendations on some things to do?

 

[BarnStang]

You should be able to advance the timing a little more. That will help. You should be able to run at least 10 degrees initial on 87 octane. Get a vacuum gauge and tune the idle air mixture screws for max vacuum. Make sure you reset idle and set mixture again. I think the timing is holding you back if it's running good and sounds smooth.

 

[JDS68Stang]

Here's a good post on timing from a vette forum, C3s (68-82)
I've seen similar posts here, just have to do a search, a dial back light is recommended and get all your advance in by 2,500- 3,000 PRM, @36 degrees, I believe the prior posts here were that same recommendation
http://forums.corvetteforum.com/showthread.php?t=1430339

 

[D.Hearne]

With a stock 289 cam, it ain't gonna be happy with 87 octane fuel. You'll need 93 premium with the stock cam.

 

[Internexus]

Thanks for the posts gentleman!

I will begin tomorrow with the 10 degree mark and see where I end up at, is the idle being at 1,000rpm okay I am assuming?

I am having a little bit of a hard time adjusting for max vacuum with the idle air screws because the gauge kind of dithers a little bit and I cant really tell if there are differences in vacuum without doing large adjustments it seems. Definitely not the way we are aiming for haha. What is the best way to do this considering you want equal tune per bank and you can't really pin point appropriately like this? I am honestly thinking of having a bung welded onto each header and putting my wide band on each side and going for a drive, adjusting as necessary.

I will check out that thread tomorrow, getting ready to climb into bed at the moment...

As for the cam, I known it is an aftermarket cam, but don't know the specs or anything about it, I would assume an RV equivalent to be honest with you. The highest octane we have is 91 which is equivalent of garbage.

 

[BarnStang]

Either a vacuume leak or the aftermarket cam is making things difficult. Sometimes you just have to find the best reading you can if it's wandering around a lot. You may have to just tune for good drivability and throttle response. Oh, if you're at 1000 rpm, it's possible you may not be in the idle circuit yet. THat would also make it tough to tune the idle mixture. If you can't get the idle any lower without it dieing on you, you can also pull the carb and look under it to see if the transfer slots are exposed. THere are some other things you can do if this is the case. You can also try advancing the timing past 10 initial. Not sure how much advance it will tolerate with that cam. Would be better to know the specs on the cam. Make sure you are actually into the idle circuit and post back.

 

[Internexus]

Have it set to about 10 degrees of timing, the idle/air mixture screws dialed in to the vacuum and in park it runs at about 1,000rpm and in drive its at about 750-800. Do have issues of it idling rough for a few moments during initial start after its already been warmed up and also having a hard time during cold starts getting it to idle smoothly but it sure runs a lot stronger during wot at operating temperature.