Okay mate, I'm doing the same thing!
First off, recheck Jacks info in the Tech section by clicking on the Ford Six icon.
The standard list rockers are
Big block 396/402/427/454 Chev, (Rat to 1965 to 1986)
Big block 370/429/460 Ford, (385 series, 68 to whenever)
Small block 302 Boss (69-70)
Small block Cleveland based 351C/351M, and 400 Ford. (335 series 70-80)
3.8/4.2 Ford 90 degree V-6 (Called Essex, found from 82 to date in Foxes, Taurus, F150 etc)
There are aftermarket roller rockers of varying types. The issue with the rockers is that they don't stop the ocassional stud pulling out. They do reduce side loads on the exhast valve, protect the guides, and stop the valves dropping under heavy revs. The best option is 7/16"posilocks, and Yella Terra guide plates, hardened pushrods, and never having to ever touch them again.
Retainers, use big block Chev Isky, keepers are Ford, sled fulcrums are Ford/Chev, rocker posts are light duty but will be okay if not reved hard over 5000 rpm. Good Boss 302 or 351SCJ valve springs can work well. If you want to, you can run fully adjustable valve gear with hydraulics.
The lifters to use are good old Cleveland and 351m/400 items. If your welding the block or using the stock 7.83" deck, the pushrods are pre 3800 buick ( the 231) , and use cut down Cleveland stainless valves if you get stuck. Valve length varies, so its really important to ensure the correct preload is reached on clamping the bolts down. An adjustable pushrod from Crane, with a collapsed new lifter, is the best option if you are unsure.
The distributor is not a big issue. Henry Ford said. Built it well. If we don't use it someone else will. That means putting the dollars in retuning a Petronics or Duraspark will pay off better than the cost of mapping DIS/CDI or other more modern systems. If you were running a full SDS system, then you are spending more time chasing black cats in black rooms, rather than dealing with the comerical reality of making a Hybrid 200 work. When I see people talking electronics, but not building cars as a result, I know the project is going to die.
If you are using the stock 2-bbl Weber intake manifold with the DGAS 38, ADM 34, or Holley 2300, just add a 8.15" to the distrubitor drive in the manner of the old Austin Healy 3000. Have a machinist redo the shaft so it sits above the intake. Then space the intake manifold out 35 mm with alloy gaskets.
If you are planning to use the stock XE/XF EFI ports, just modify the fuel rail, and add the longer distributor.
The common aftermarket Redline triple Weber DCOE 45 intake will just clear the distributor if its shaft is raised 8.15". The trick is to make sure the carb is no closer to the distribtor than it is in a tri power V8 or dual quad V8 engine.
The rest is simple. I differ from Jack in that I plan to use an expoxied 125 thou steel plate with the room for the pushrods gained by steel plate expoxied in. This allows you to run a set of ACL 1.163" pistons of 3.68 or 3.71" diameter, and a set of Lima 2300 rods with the smaller 0.912" wrist pin and 2.3 big end bearings. You then have to use the correct pushrod length. The ring lands park some distance below the block, and the split line from the new false block topper is solid and won't we a detonation area.
Locking up adjustables pushrods via welding up is an okay option as they are frequently loose and you don't want any unfavourable rocker geometry becasue even the super short 200 Hybrid has heavy valve gear. This was an old Repco Formula 5000 trick from the early 70's.
The cam needs the extra links from a high performance chain crank and cam gear. FordSix Performance sell them. All Aussie Falcons ran this since 1971 or so. The cam profile is better off being a mild 270 item from Crow, with moderate 50 thou figures. In a 250, it likes 280 and 215 figures, but loosing 25% of stroke makes the little 200 suffer from a choppy idle. The exsiting cross flow port size is fine.
If you work on keeping the block modifications simple, then you will a have the lightest, shortest post war cast iron six in line engine in the world, with a full inventory of great parts.
The weight of a Ford six is proportional to its height. With 7.83" deck, the 200 is 385 pounds.
The alloy head looses about 55 pounds of the 385 pound seven bearing log, is now about 330 pounds.
This is lighter than
348 pounds 2800 Capri (Motor, 1978)
364 pounds 2800 Capri Injection (GB Motor, 1978)
365 pounds four bearing 144/170 I6 (Ford press material)
400 pounds US Windsor 255 was only (1980 press release)
432 pounds 3000 Capri British 60 degree Essex V6 (1978 GB Motor)
450 pounds US 221/260 (no PS, no AC, Rodger Huntington)
470 pounds US 289 (no PS, no AC, 2BBL, Rodger Huntington)
470 pounds US 302 (no PS, no AC, 2BBL, Rodger Huntington)
481 pounds Xflow Alloy HEAD II with the alloy head (no PS, no AC, 1-BBL , no EFI, Angus Mackenzie, Street Machine 1990)
490 pounds US 300 I6 dressed (no PS, no AC, 1-BBL , no EFI)
531 pounds, wider Oz 250 cross flow had a dressed weight with the cast iron head,
537 pounds Alloy Head EFI (because of the heavy alloy plenumb)
540 pounds US 351 W (no PS, no AC, alloy intake 4BBL) Rodger Huntington
562 pounds US 5.0 with EFI and all ancilaries (PS, A/C, fan, alternator, starter) Wheels Ford Press Release 1992 EB Falcon
577 pounds US 351 C (cast iron intake, 4V heads, manual flywheel, no ps, no ac) Hot Rod Magzine, 1988
719 pounds Aussie 351 C 2V (with PS, iron intake, Selectaire A/C, fan, alternator, starter), The block is only 20 pounds heavier.
Other notibly light Engines
267 The Alloy Buick was about in the Rover,
267 pounds for the 1.6 Kent Pinto OHV (all dressed to run, Haynes)
289 pounds for the 2.0 2-bbl Pinto (all dressed to run, Haynes)
306 pounds for the 2.3 2-bbl Pinto (claimed in 82 press release of 3.8)
309 pounds for the 3.8 Essex 90 degree (may not be with all accessories)
374 pounds for the early Nissan 3.0 V6
410 pounds for the 7.414" tall block in the in-line Nissan ohc 2.0 RB20E
432 pounds for the 90 degree GM 3800 in RWD Commodore
456 pounds for Holden 202 EI, in line cast iron six
474 pounds for the taller Nissan RB 30E
Fortunately, I already have the big list of everything I had planned to buy for the valvetrain and rockers, so most of the details of the "ideal" way to build the engine (using new/performance parts) are already worked out. Eventually I will go that route and we will be talking much much more about this. 8) 
