I'd rather not of course. Hoping I can spin the stock cam around to lift the lifters but the new cam I am putting in is taller. Or maybe someway pull the rollers up. But if I gotta, I gotta.

 

The intake needs to be removed.

 

On the roller cam engines the spider and dog bones that keep the roller lifters from spinning will thwart your attempts to pull the lifters up out of the way of the cam journals.

GD

 

If you don't remove the manifold, how do you plan to extract the lifters from the bores in order to pull the old cam and replace it? And then put them back into the bores when you are done?

Pull the manifold.

 

C'mon - NASA could design a tool for someone to do this in zero-g while wearing a space suit! Also the Russians could very likely get the job done with a remotely controlled rover called Lifterokhod.

GD

 

Replacing cam and lifters without pulling the manifold is easy on a Crossfire injection engine(flat tappet)-just pull up the lifters with magnet tool,drag them back and out the dizzy hole I think stock carb manifolds don't have enough clearance above the valley to do this,but TPI or aftermarket carb might.Can't be done with roller lifters...

 

You can do it with a bunch of those cheapy extendable parts store magnets but you still have to pull the distributor. Way more work than just pulling intake. Good time to clean and port it too.