About a year ago I put a 79 450SEL engine into my 79 SLC. It was a very tight fit. Some minor work was required to get the passengerside exhaust manifold to stop rubbing the frame. I found out the SEL enigine was 2" wider and 1" taller than the SL engine. It can't be in the block so it must be in the "stacks". Also this SEL engine "seemed" to have a little more "oomph" than the SL. For what its worth. Lee Incidently, I had a nasty accident and my SLC was totalled two weeks ago.