[Chevy454]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bitfactr</div><div class="ubbcode-body">Great ideas and advice all around. Thanks.

I was all set the do the adjustment tomorrow morning. I just looked at the specs for my cam. It is a CompCams, Part # 11-671-4, Engine: CB Nostalgia LS-6+, Valve Adjustment: Intake .012, Exhaust .012. Again, the engine was rebuilt to as close to original specs as possible, <span style="color: #FF0000">and this cam was selected as being the closest.</span>

The 70's era manuals I have, while not listing the valve adjustment for the 70' LS6 specifically, lists the other solid cam big blocks (ex. L78 from multiple years, the '71 LS6 from the Vette, etc.) with lash in the range of .024 - .028.

I didn't expect such a drastic difference in the lash on the contemporary CompCams regrid; it seems to be about half of the original. Should I be concerned about this?????

I don't have the specs on the original LS6 cam, so I don't know how different the CompCams regrid is, but I included the rest of the CompCams specs here:
Valve Adjustment: Intake .012, Exhaust .012.
Gross Vale Lift: Intake .544 Exhaust .539
Duration @ .015 Tappet Lift: Intake 276 Exhaust 283
Valve Timing @ .015: Open: Int 29 BTDC Exh 76 BBDC
Valve Timing @ .015: Close: Int 67 ABDC Exh 27 ATDC
Duration @ .050: Intake 239 Exhaust 246
Lobe Lift: Intake .3200 Exhaust .3170
Lobe Separation 112.0
Specs for cam installed @ 108.0 intake center line

Lastly, I read in another thread that it would be a good idea to disconnect the &quot;power&quot; wire from the distrubutor when using a bump-switch from underhood to crank the engine to be absolutely sure the engine doesn't start. Would simply disconnecting the coil wire from the distributor do the trick?

Thanks again,
Dennis </div></div>
Well, you got some bad info on the cam...the cam you have is a tight lash cam, hence the 12/12 setting, whereas the original was 24/28 like you posted...not only are the cam specs themselves different than the original 143 cam, but the different lash characteristics will change how the engine sees the camshaft as well...I also see that it has a 112 LSA, whereas the original was a 114, which means a tad lumpier idle as well as a bit less vacuum...it's imperitive that you set the lash to the cam card, though, because tight lash cams are a bit more finicky due to their lobe designs.

With that said, your Comp camshaft will still work fine...