warhovs

Looking at building a 406 (to swap out my 350 with), just want to check and make sure that there aren't any hidden issues in the change that I'm not aware of in order to plan the job. I'm assuming that after I drill and tap a clutch shaft hole, the 406 should be a drop in replacement (bellhousing, motor mounts, water pump, any tinware I swap, etc.).
:steering:

Glensgages

Yes, exterior dimensions of the big-bore Mouse are the same as all small-blocks...
400 CIDs have a tendency to run a bit warmer than 'most' others; is your cooling system up to the task?

The Dude

Make sure to have a machinist drill the proper steam holes in your heads. Other than that, if your cooling system is in proper working order, you won't have any "issues."

Other than that, the the possibility of a couple of extra freeze plugs, and a new balancer and flexplate (if you have an auto), it's a direct bolt-in. And, since the 400 is a bigger engine, you have to remember it will like bigger parts. This is especially true in the camshaft department. The cam that's really lopey in a 350, for example, will smooth out considerably in a 400.

Have fun.

The Money Pit

The 400 is externally balanced so you'll need the correct flywheel if you're keeping the stick.(I wish mine was a manual) :yesnod:

Jack71

With deck plugs and steam holes drilled in your heads you shouldn't have any overheating problems with a close to stock motor. I had a 400 in my last vette and the stock radiator handled it fine.

I'm putting a 400 in my current vette now and went with an internally balanced engine. If your building a 406, might as well go with internal balancing.

Strong engines in these cars, you will love it...