Post up what you find out so I can use the info...
Talked w/ the guys at Modern Driveline today.
Told them what I had ('70 mustang w/ 289, 4 spd toploader and 9" rear) and also what parts for my conversion I already had (trans, late model bellhousing and clutch lever, clutch and pressure plate).
These are the additional parts they said I needed:
Clutch cable kit ($259) since I have an aftermarket brake booster it would make a hyd conversion difficult at best. They also said that the cable kit should work w/ any booster less than 10". In terms of headers, they said that the best way to tell is to bolt up the bellhousing to the engine and hold the clutch lever in place and make sure you have at least 6" from the lever before the cable needs to be bent to avoid headers, etc. They said that if it won't fit and I don't want to modify my headers then I can just keep the mechanical linkage as is.
Clutch lever cover ($48)
Block plate ($55) If not already on the bellhousing.
Crossmember ($149)
Rubber trans mount ($19). They said that if mine was recently replaced then it would be fine.
Speedo cable for automatic ($26) The toploader cable is too long since it attaches to the passenger side of the trans and the T-5 attaches to the driver's side.
Speedo gear ($9.50) Tell them what rear gears and tire diameter you run and they'll send the right gear.
Backup wire harness ($15)
Amsoil ATF fluid ($29.85)
Installation hardware ($30) Bellhousing and trans bolts.
Total $640+/-
They also told me I needed a fulcrum adapter if I use the cable clutch and late model lever but it wasn't on the itemization.
They were very helpful and I would definitely call them before ordering so you know exactly what you need and what to check for.