I know there is a fiting to put in a spark plug hole to fill the cylinder with compressed air so the valve doesnt drop. My question is how big is this fitting and is it possible to use it with the horrible plug access the SLP dual cat shorty headers have. I would like to do a cam install and this has a lot to do with whether or not i will go ahead with the project or not.

Or will my only option be to put each cylinder at TDC.

 

I would use the TDC method. The compressed air method frightens me. It's nice knowing that there's something physical holding up the valve stem, not air. And if you replace the valve seals...yeah.

It's also nice to have about 1/2" of play in the stem to fiddle with the keepers and retainers.

 

Plug access is simply too difficult to use the adapter and hose. I'd forget using compressed air and use the TDC method.

 

Thanks for the help guys. I figured i would have to do it that way.

 

Save yourself some time and dont bother. You wont drop a valve on a stock stroke LT1. Do all 16 at once, THEN lash. Will save a lot of time. Use a pen magnet to hold the valve up if the valve seal doesnt (it should).

 

You are probably right about this method, but I don't feel comfortable relying on the seals to hold the valve up. I know I would screw up and drop a valve.

With stainless valves, its not a good idea.

 

As Spinner informed me a few months ago, the stock stroke of a LT1 wont allow a valve to fully drop.

 

Like I said, you CANT drop a valve, period. The piston doesnt travel down far enough for a stock length valve to fall through the head.

 

I didn't know that.

I do know that I can drop a valve on my BBC engine. Since I found that out the hard way I would rather be safe than sorry.

 

I did one better. When I was doing headers and cam, I changes my springs by using a set of long needle nose pliers with rubber boots. I noticed I could either slip them to the side and the side pressure was enough to hold the valve up, but I put the jaws around the valve stem in the intake port. The insulation around the handles held them in. I could see a rag doing the same thing. I just used my finger in the exhaust ports, I used the compressor to compress the springs, held them in with my finger, and pulled them back slightly to break them loose. Worked fine for me, 30 minutes with no problems! I had the intake off though...