A while back I purchased a 560sl to join my mercedes fleet. I thought it was a good deal, but it has white smoke upon start up. I am currently doing the repair/replace analysis I began thinking that while I was at it, it would be nice to get a little more horse power out of it. In researching the internet, I found that the sl 560 was de-tuned for the US market, that the SEL/SEC has more horsepower. Also when investigating, it appears that used sel/sec engines are less expensive than the sl motors. One other thing I found was a web site (carcentric) where an individual transplanted a 560 SEL engine into a 72 350(450) sl and it sounded as if it may be within my mechanical aptitude. I know from experience that reading about an engine swap is alot easier than doing one. I am interested in your perspective of transplanting a 560 SEL/SEC engine into my SL.