Cost to change cams in 3.0 SC
 

What is a estimate of the number of hours to switch cams?
Specifically from 20/21 webcam camshafts to stock cams.

I'll assume you are doing this yourself

if you have never done it before, and the motor is in the car, and you have all the tools

drop the motor, remove the old cams, install the new cams, do the cam timing, and install the motor

20 hours

this is just a guess

I replaced one of my timing chain housings a decade ago and it took a while but it wasn't overly difficult with the right tools.

It is recommended to do rockers.

If you’ve done it often, I can see dropping a motor and changing a cam in 20 hours. If you have never done it, figure a year... :)

All kidding aside, I have rarely seen someone remove a car motor, for any reason, and seen the same car running within a year...

If my memory serves me correctly, book time for an overhaul on a flat six was between 45 and 60 hours, depending on the model. Smogged out turbos were at the higher end of the scale. 20 hours seems generous for just replacing the cams.

Even those seasoned professionals in the know run into "...while we're in there..." so hope for the best but prepare for the worst if you're paying for the job.

The typical conversation goes like this.
"I would like the cams changed in my 911. I have my own cams and rockers"
"Ok, 20 hours labor, plus any other parts, and obviously we won't warranty those cams or rockers if something goes bad. We'll have to remove the engine and transmission. Oh, by the way, when was your last major service? What about the clutch? Does it leak oil? Does it use oil between oil changes? Do you want us to check compression and leak it down? Any problems with the transmission, since we have it out?" "And of course we'll test drive it before hand and check for unusual noises and things like that."

And so it goes. Just being honest here.

Book time is 11.2 after engine is removed.

Cheers

Isn’t it possible to swap the cams with the engine/trans still in the car (partial drop)?

Yes, but why? Removing all 12 rockers, the cam carriers and timing the cams isn't something that I'd want to do in the car. It's really no big deal to drop the engine and trans, then put it on the stand to make everything more comfortable and easier.

Just thinking that it might be possible for the OP to save some $ with a shop if they didn't pull the motor.

Camshaft switch........
 

How do you expect to pull the camshafts with the motor installed. Professional shops will install the motor on an engine stand and do the work. They don’t rebuild motors squatting on the floor.

Tony

Thanks to all for this insight. I’ve since overcome a need to do this since I’m convinced a 20/21 cam is nearly as good as stock cam from an emissions standpoint.

Since a pro told me 50 hours for a full teardown rebuild I figure 20 - 30 hours for cam change.

That made me laugh :)