center sump oil pan helps, but the demise of the sunbeam tiger came when chrysler took it over and didn't have a v8 that would fit...
The sump may be an issue or may not be, Actually the outside dimensions aren't that much different than a flathead. Popular American V8 Engine Dimensions (carnut.com)
The 331 I mentioned earlier is rear sump. In the case of the Sunbeam Tiger the problem wasn't the sump, but the LA having a rear dizzy, where the SBF was front dizzy.
Gold Mountain is correct. Vans and pick up trucks have a rear sump. But be careful not to get a 318 pan. It won't fit the 360's larger mains. Gene.