I always thought that the 2.0 rockers with the 10MM adjusters were lighter than the 1.7/1.8 with the 8MM adjusters were somehow lighter to compensate for the heavier 2.0 valves . I just measured the weight on a digital scale. 1.7.1,8 small rocker 137.95 gm and the larger one 145.91 gm The 2.0 rocker with the 10MM adj were small 140.70gm and the larger rocker at 156.75. This is with the adjuster screws and nuts installed. I have no idea if this makes a difference when they are rocked , some one with an ME might want to reply.

Type 1 tool steel lifters 53 grams versus 137 grams for a type IV lifter! And we have 8 of them! Sleeve the type iv case and run type 1 lifters. Easy choice.

And where weight really counts,, only 564 grams for an Empi 5500 I-Beam rod, not sure what a 2.0 liter of 1.7/1.8 rod weighs, but it's more. Run light weight pistons too.

The weight isn't generally an issue for the RPMs that the stock 914 motor sees.

From my reading, the later adjusters were larger to make the valve adjustments slightly less fiddly, and to offer a larger wear surface to reduce the overall amount of wear from the adjusting lugs operating on the valve tips.

--DD