I hope I'm not the only one ignorant about automatic trans. I'm building a 6 liter gen3 gm motor and I want to know about manual valve bodies and how to actualy use them. And if anyone can help me about trans selection. Do I need to use a 4L60E or can I go with a 700r4? Is a manual valvebody like a sequential manual gear box? I appreciate all the help I can get  

Despite what people may think/say, automatic transmission's are THE way to go. No humanbeing can shift more perfect or as efficient or consistantly as an automatic. And, personally...I'd say ditch the overdrive transmissions all together. Go with a TH400 & if an overdrive is a MUST - drop some cash on a gearvendor. The money you'll spend on building a R4 to the equivalent of a TH400 will destroy your wallet. Also, full manual valve bodies aren't really great for the street, I suggest a manumatic (you can still hold a gear & downshift on demand) that way you aren't constantly having to shift up & down.  

TH400's are incredibly inefficient...and really shouldn't be used unless you are putting a TON of power to it, or its the only thing you have.  A TH350 is much more efficient...and can be built to handle as much power as a TH400 for not a lot of money.  A gear vendors unit is well over $2000 ON TOP of the TH400 you'd end up buying.  Thats really not any better price wise than buying a built up 700-R4 or 200-4R.  I built my 200-4R for around a grand with all the goodies neccessary to handle more power...TCI sells them for around $1500 I think.

As far as the 700-R4 and 4L60E...the E means electronic...so you'd have to buy a controller for it.  The 700-R4 would only need a lockup converter kit...which isn't very expensive.  And actually...I'm pretty sure you can get a valve body that will get rid of the lockup feature.  That will allow for a lighter torque converter...but you'll lose that extra bit of efficiency on the highway.

I have the manual/automatic valve body (actually...I have a shift kit that turned it into a manual/automatic valve body)...I like it.  I'd recommend it.