Both!!
Throughout the Lotus production run the blocks were selected 1500 cc pre crossflow. There is an L cast into the side of the block to identify it for Lotus. After the production ceased at lotus they were supplied as kits to Caterham. After the 1500 blocks were nolonger available , twin cams were built based on the 1600 Kent crossflow block, with GT crank and rods, and Lotus pistons.
The block was machined 0.250" and a spacer was inserted on top of the timing case, so to restore the correct height, and the timing chain lengthened by two links with a revised tensioner mechanism. All this resulted in a taller engine, by about 3/8"
I guess sump will need to match block type.