429 Thunderjet. 360 HP. Usually came in Thunderbirds, standard Torino Cobra and LTDs. Same as a 460 Lincoln engine with less cubes. It was a torquer for the big cars. Not available in Cougar or Mustang. hydraulic lifters.
429 Cobra Jet. 370 HP, probably a little more. Optional in Torino Cobra, Mustang, Cyclone and Cougar. Not available in big Fords, Mercs or Thunderbird.
429 Super Cobra Jet. 375 HP. I think it had an oil cooler and steeper gears (Drag-Pac 3.91 or 4.11s). Mustang, Torino or Montego only, no Cougars. No big car applications. Mechanical lifters.
BOSS 429. 69-70 Mustang BOSS 429 only. Semi-Hemi. Bring $$$$$
Boss 429s are not all that cracked up what they're supposed to be. Trust me on this one. My buddy has a 69 Boss 429 Mustang. Very maintenence intensive. Not only do you have the headache of adjusting valves (and it can only be done with the engine running), but you're talking about very specific (and rare) parts! Just a set of valve cover gaskets will set you back fifty bucks or more if you can find them!
My buddy just had to do a head gasket job on his Boss. If you have ever seen that nightmare, you'd know what I'm talking about! There is no 'head gasket' really, just a bunch (I think 26/head) of teflon coated o-rings! Every oil passage (one per rocker arm plus the drains), every water passage, and each cylinder have individual o-rings. Just try to keep them all lined up as you lower the head into place.
Now why did he have to do the head gasket job again on a car with less than 3,000 miles since it was put together? Short answer - Heat cycles. The different rates of expansion between the cast iron block and the massive aluminum cylinder heads cause movement. This movement, over many heat/cool cycles will shred the teflon coated o-rings, causing leaks. Oil leaks, coolant leaks... what a nightmare! The only fix is to replace all of the o-rings on that side.
To do this in the car you must either have the patience of Job, or you pull the engine. There isn't a lot of clearance between the heads/valve covers and the shock towers -- and remember that they already modified the shock towers on these cars to get the engine to fit at all!