I have two olds engines.One is a olds 403 and is not working.The other is a olds 307 and works but throws white smoke.Can I swap parts from the 403 to the 307 to fix the problem and to add power to it?

 

Not the heads, which may be the culprits of the white smoke. Year, make and model would help out too. Welcome to CO.

 

Welcome to the site!
What is wrong with the 403?
Fixing it would be the better choice, no matter whats wrong with it...
The 307s have limited potential.

 

Yes, you can. Jack up the air cleaner of the 307 and swap everything underneath.

Seriously, it depends. Both motors are small block Olds motors, so much is common, however as noted above, your smoke problems likely require repair to parts that are unique to the 307. It also matters whether the smoke is wispy white (water) or heavy bluish white (oil).

 

Welcome to the site. Are you sure its smoke and not steam. Does excess water drip from the tailpipe when the engine is running. Have you checked to see if the water in your radiator is low. Could be a blown head gasket

 

403 olds came out of 77 trans am,has 4A heads,block casting # is 557265 4B.The 307 olds casting # is 479OGM5.0LG. Dont know what car it came out of or its year.

 

moved this to the appropriate section where it should see some more activity.