I just had a crazy idea. I’m a ‘78 Toronado owner with a 403 that’s going bad (probably rebuild within the year) and I’m seeing tons of 455 engines around marketplace. How hard (hypothetically) would it be for me to yank out the 403 and smack in a 455? From what I understand, even though the power would almost double, I wouldn’t need to mess with the transmission due to it being the same one used for earlier toros. I’ve been trying to look at the engine mounts between older/1978 chassis’ to see how much of a pain this would cause. Thoughts anyone?

I should clarify that this is much more of an intrusive thought than a real plan. I’m not taking this seriously!

 

The 455 should bolt up the same, it’s just slightly taller and wider than the 403. So the question is will there be enough hood clearance? The Toro 455 engines use a sunken intake manifold for hood clearance.

 

Its somewhat heavier than a 403 and the Toro uses a torsion bar suspension in front. You'll need torsion bars from a earlier car to restore ride height. You'll need exhaust manifolds from the earlier car too. It might be less trouble to get a stroker crank from Cutlassefi and rebuild your 403 to a 440-450cid small block.

 

How would I do this?