Here is a list of parts and prices for what I used for my TH400 swap. I tried to find a complete list a while ago but couldn't, so this is for all the people that do a search in the future.
The car that I put this trans in is a weekend bracket car so I was after consistency more than anything. There are different ways to do some of the things, but this is how I did it.
Trans; the important part. Luckily I have a friend of a friend that builds racing transmissions so he built mine for me. It's got the big sprag, hardened drum, Alto Red's, TransGo kit, hardened shafts, deep pan, adjustable modulator, he worked the gears a little bit and did a lot of other stuff that's over my head. Guaranteed it for 900 HP so I think it'll do OK behind 430. He sells this trans for $1275.
Convertor; I went with a Hughes since I've always had good luck with them. I called them up and gave them the specs on my motor and faxed over my dyno sheets and car info. They spec'd out a 10" 3500 stall converter and it ran me $680 but I'm a dealer so that was my cost. I'm not sure what retail was. Their off-the-shelf converters hold up well too. I've used them in several cars with good results. They retail for $435.
Flexplate; You can get away with the stock piece but I grabbed a TCI SFI approved piece since my stocker was old. It's up to you, a new one will run you about $80 but spinning to over 6000 rpm's I feel safer with a high quality flexplate. Also swing for the ARP bolts.
Shifter; I rigged up my stocker to work for now since my B&M wasn't here in time. You can use your stocker but your indicator will be off. No biggie. When it stops raining I will be making mounts and modding the shifter plate to fit the B&M Magnum Pro Stick. Figure $175-200 for a decent shifter.
Trans crossmember/torque arm; You can either get the B&M or Hurst kit to adapt the crossmember and torque arm or you can go with the Spohn torque arm. Chances are if you need the th400 then you'll benefit from the adjustability of the Spohn piece. I wasn't about to try to tune the suspension with a stock torque arm so I went with the Spohn piece. It moves the instant center farther back, it gets the torque arm off the trans tail housing and onto the frame and it lets you adjust the pinion angle. Not to mention it's stiffer. For a street that you don't plan on racing a lot, the Hurst kit will work well. Hurst kit is $135, Spohn is $395.
Driveshaft; Most say this is the hardest part of the whole swap but it isn't that bad. The stocker is too short and finding a usable core at a junkyard that you could shorted is a pain. Not to mention it would cost you as much as a new one by the time you get it, new joints and shorten it. Once you get the transmission in and the torque arm installed you need to measure the length for your new driveshaft. Measure from the face of the end of the tailshaft to the center of the rear u-joint. Call up your local driveshaft shop and tell them what you're doing. They will know which joints to use. I called up and told them that I needed a DS with a front yoke for a TH400 and a rear joint to fit the stock 10 bolt and gave them the measurement. Had them make it out of 3' .083" wall thickness DOM seamless tubing. 3 hours after I called them the called me back and told me to pick it up. Total was $260.
Trans cooler; you'll need to add an additional trans cooler, especially with a high stall converter. I used the 2nd biggest Perma Cool trans cooler I could find with -6 an fititngs. That ran about $60, 20 ft. of -6 braided hose, $80 and another $90 worth of fittings. Expensive but well worth it. Cleaner install, more durable and reliable than rubber lines.
Dipstick; I'm sure that you can find a stock GM dipstick/tube that will work but I just got the Lokar braided one. Easier to install and it looks better. $50
Trans Mount; Pick up a good poly mount. Around $25. Energy suspension better than Prothane IMO.
Bolts; Hit up ARP for some good flexplate and torque converter bolts. Just a little extra security. Be sure to use a little blue loctite on them all.
Kickdown switch; I didn't use one, but all you need it a momentary switch up on the gas pedal under the dash to supply 12v. to the kickdown switch on the side of the trans. Search the bone yards for any car or truck and snatch the switch off the pedals and adapt it to your car.
Temp Gauge; Any car with a high stall converter should have a trans temp gauge to keep an eye on the temps, ESPECIALLY bracket cars. Autometer electric gauges work great and can be had for less than $60. Be sure to mount the sender in the pan before you fill the trans with fluid.
Odds 'n Ends; Don't forget all the little stuff! Fluids, nuts, bolts etc.. A drain plug is a good idea and makes fluid changes a lot easier.
This is how I did everything, not to be taken as gospel. Just trying to put most of the info in one place for those doing their own research.
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