Hey guys,

I have a 1980 Camaro with a 67' 327 under the hood. I'm wondering what the timing should be set at? The cam I'm running is a Comp Cam (Part # 12-212-2), it has .480 lift. I'm not sure if the cam makes a difference on the timing, but I figured I'd just add what one I'm running.

Thanks for any help
Matt

 

Some performance cams like a little more advance than stock but not sure on that one,not a big cam so I think you'd be ok with stock timing specs but you could go to the comp cams website and look it up or call their tech number.
http://www.compcams.com/cam_specs/

As for a stock '67 327 ,there were a few different engines not all the same,some were mild and some were wild like the 375hp solid lifter cam'd Corvette 327.
Most would be somewhere between 4 & 8 degs BTDC,you may have to play around a bit to find it's happy spot.
Make sure you unplug the vac advance unit and plug the hose first.

 

It's interesting how some "old-old school" practices are still handed down!
Disconnecting the vacuum advance was necessary in the sixties and earlier, before the smog days, when the distributor was hooked up to manifold vacuum. But now, unless the distributor has been modified, the advance is hooked up to ported carburetor vacuum (the smog way). And that port has NO vacuum coming out of it at idle. Disconnecting the hose is a wasted step, unless his advance is hooked up to manifold vacuum.
Oh, and I would shoot for 8-10 btdc timing and see how she goes.

 

I actually have upgraded to a digital ignition. I have the more mild 327, according to my Chilton's; the engine code (I believe it's ME) states the engine has 210 Factory horsepower I think I'm going to shoot for around 8 BTDC and see how she responds.

Thanks a lot for your help

 

I'm running the same cam in my 350 sbc with 1.6 rockers for .512 lift. My idle is strong starting at around 16 - 20 degrees with a very narrow advance curve. Just make sure you have a good battery with strong cranking amps and thick battery cables to supply the starter enough cranking power at that range. Your ABDC is 66 so you lose a lot of low rpm dynamic compression and advancing makes up for it to give it a good strong idle.

Camaro69> Most instructions tell you to disconnect your vacuum advance still. The weight set from Accel tells you to disconnect as does Mr. Gasket, MSD, Moroso, etc. I know the ported vacuum is vacuum created in the venturi as air passes through. Even at idle you're having air coming through the venturi and it is pulling just a little (atleast on Holleys). I know that's where it reads vacuum for the vacuum secondary circuit (it's in the passenger side venturi right in the bottle neck). The one for the ported vacuum comes out right above the same venturi's throttle blade. It may be enough to throw off one degree or so but in big block applications with 750+ cfm carbs it might be significant to throw it off more. When you're at idle you have vacuum on the manifold and that vacuum port's origination point is right by the only outlet for that vacuum. It could pull a little I would assume. With messing with the timing also you're affecting vacuum on the manifold.

Not that I'm saying you're wrong or anything... You're pretty much gospel on a lot of things. ;p


Also, depending on how high you have to set your idle screw you may be putting that ported vacuum below the throttle blades. The two 3310's I have sitting on my desk right now that are disassembled are both with their throttle blades right across or just below the port (about 0.010).