Hey guys...how feasible is it to change a cam in the 400 while it's still in my 68 bird? I've never had these engines apart, so I have no idea how difficult this is with the engine in the car. My only question is if the oil pan needs to be unbolted to remove the timing cover, & if so then is it in my best interst just to pull then engine? Thanks!

I will pull it. There are other things you may end up doing as well. Much easier to work with

It's not hard at all. Just pull the radiator.

It is a little bit of work but it's doable. You don't need to remove the pan, just the 4 bolts up front that thread into the timing cover.

ok, that's what i was wondering. I still haven't found a cause for the miss while i'm driving it so I want to check out the timing chain & the cam currently in it. The guy I bought the car from has no idea what cam is in the engine so I'm thinking the problem may lie there. Thanks guys.

It's unlikely your miss is caused by your cam. More likely ignition or fuel related. If the timing is steady, the chain is probably good. I'd do more diagnosing before you start pulling things apart.

I changed my cam with the engine in. It was not hard- just take the radiator out and the rest is easy.
Also, I had a stretched chain when I first bought my car many years ago. It did not cause a miss- it just made the car verrrrrry slow.

I've tried everything to fix the miss. there's no miss when it starts up, idles, or when you punch throttle. the miss is there at ordinary cruising speed which baffles me. i've changed carbs/msd box/distributor/wires/plugs/fuel pump/coil with no luck. offically stumped. a tech at msd & holley said to take a look at the timing chain & the cam to see if something wrong with the chain. welcome to this nightmare....

I had a similar problem. Think I found the solution after I torn down the engine...

To check for a stretched chain, pop off the distr. cap and rotate the crank manually back & forth. I think its a 15/16 socket. Rotate it one way and watch the distr. rotor, then rotate the other way, it should track instantly (no lag before it starts to move). Can also pop off a valve cover and do the same thing when one of the valves is lifting up.

Cool trick!

Great tech info!!

Hey Gus68,


Do you happen to know what brand your timing set is? Thanks

Could be chain. i see you've changed everything you can. Is the miss worse under load (going up a hill in 3rd on the highway) What are you running for timing? Initial, vacuum and mechanical advance? Are you using manifold or ported vacuum? Have you ever tried switching from ported to manifold or back. Have you done a recent compression check on all cylinders?

If it was chain I would think it would be rough all the time.

Also check the voltage to the (+) coil wire. I know the stock '68 wires (and maybe other years) were a resistance wire meaning they only had 9 volts to the coil when running. The HEI's and MSD's require a full 12V or strange things happen. You can try a jumper with a wire direct from the battery to the coil but remember you won't be able to shut the engine off with the key and you'll have to pull the wire off to shut it down. Set it up with a clip or a way to pull it off. Also don't leave it hooked up very long without the engine running it can be hard on the coil.

I had a miss in my motor that drove me crazy. Cruising speed with light acceleration. Accelerator pump spring.

As soon as spring breaks, i'm going to tear it apart then. it's in winter storage now until around april....the joys of living in western PA. the last owner of the bird has no clue what the cam is in the car or when the engine was last rebuilt, so that's the first place i'm going to check, the timing chain. thanks!