th350 or th400
09-01-2005, 12:01 AM
#1
10 Second Club
Thread Starter
iTrader: (9)
Join Date: Jan 2004
Location: Daytona Beach, FL
Posts: 560
Likes: 0
Received 0 Likes
on
0 Posts
th350 or th400 I am tired of breaking things with the six speed. Which trans will give me problem free operation with about 600 hp on spray?
09-01-2005, 12:38 AM
#3
TECH Fanatic
iTrader: (1)
Join Date: Nov 2002
Location: Venice, Ca
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
I would do a th400 with the spray. A th350 could be built to hold that much, but the th400 will last longer before needing a rebuild. With a th400 you may be close to the shift point with 4.10 gears in the quarter mile. About 129mph is what I have seen with 28" tall tire and 6800 shift point. If you plan on running quicker then you may need smaller rear end gears. Just a heads up. 
09-01-2005, 07:08 AM
#5
10 Second Club
Thread Starter
iTrader: (9)
Join Date: Jan 2004
Location: Daytona Beach, FL
Posts: 560
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by SUX2BU
Search is your friend.
https://ls1tech.com/forums/search.php?searchid=2073401
https://ls1tech.com/forums/search.php?searchid=2073401
Yeah, but if I just searched I couldn't make a post with my new banner in my sig. Thanks for the generic ls1tech smart *** answer. It isn't like I asked what transmission fluid everybody uses for the 1,000,000th time.
09-01-2005, 02:52 PM
#6
TECH Fanatic
iTrader: (1)
Join Date: Dec 2004
Location: SW Iowa
Posts: 1,016
Likes: 0
Received 0 Likes
on
0 Posts
Whoa, settle down man. Personally, I would look into a TH400 if you really plan on runnig that much hp when onthe bottle. A TH400 can be built to take that punishment reliably cheaper than a TH350 could be. I think I got my TH400, built to take nearly 1500 HP, out the door for about $1400, and that was with the RMVB, 'brake, and converter. That was quite a bit cheaper than a built up 4L60E.
09-02-2005, 03:34 PM
#7
LS1TECH Sponsor
iTrader: (33)
Join Date: Jul 2002
Location: Out on the farm in Central IL
Posts: 4,399
Likes: 0
Received 0 Likes
on
0 Posts
I am going TH350. It is being done with Jay Bilingsly and his trans shop. They plan to offer a kit once it is done. The TH350 is a lot lighter and eats less HP. Yes a 400 is a little cheaper but the 350 can take the HP.
I should get mine next week.
I should get mine next week.
Trending Topics
09-03-2005, 10:10 AM
#8
On The Tree
iTrader: (6)
Join Date: Jun 2005
Location: Middle Tennessee
Posts: 110
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by redline2k
Yeah, but if I just searched I couldn't make a post with my new banner in my sig. Thanks for the generic ls1tech smart *** answer. It isn't like I asked what transmission fluid everybody uses for the 1,000,000th time.
09-05-2005, 11:45 AM
#9
Banned
iTrader: (19)
Join Date: Jun 2005
Location: chitown
Posts: 1,879
Likes: 0
Received 0 Likes
on
0 Posts
i have a 400 in my car... did the swap from a 6spd (also tired of breaking parts). it eats up a LOT of rwhp! i have a used stock t350 that i was going to have built... i'm kinda wishing i did that. i say w/ 600 on an adder...... go 350. if you have a motor that's putting out that much power, and then putting an adder on top of that. i say go 400. just my two cents.
09-07-2005, 11:08 PM
#15
i've built several TH400's my self. they are very strong in stock form
the only aftermarket part you'd need to 500 hp would be a hardened intermediate race and maybe a 36 element sprag.
leave out all but one checkball and drill out the seperator plate. I also flip the accumulator upside down with no spring. very strong and firm shifts at WOT and soft as butter at part throttle.
i've got a th400 right now that is completely stock 1968 trans, i put the race, sprag and drilled the seperator plate. it still has the original clutches and steels, i did put in a new band, but it is the best shifting trans i've ever had.
TH350 is strong too, not as much as a 400 in stock form. again, they too need the hardened intermediat race. about $50 from Summit.
One neat thing about a TH400 is some of the early TH400's from the mid 60s have a torque converter that can change pitches. two different stalls with a push of a button. there are some aftermarkets making torque converters and kits for this. all you need is a pump and stator support from one of these early 400s and put it in. one mode you could have nice 2200 stall, flip the switch all the sudden about 3600 stall.
the only aftermarket part you'd need to 500 hp would be a hardened intermediate race and maybe a 36 element sprag.
leave out all but one checkball and drill out the seperator plate. I also flip the accumulator upside down with no spring. very strong and firm shifts at WOT and soft as butter at part throttle.
i've got a th400 right now that is completely stock 1968 trans, i put the race, sprag and drilled the seperator plate. it still has the original clutches and steels, i did put in a new band, but it is the best shifting trans i've ever had.
TH350 is strong too, not as much as a 400 in stock form. again, they too need the hardened intermediat race. about $50 from Summit.
One neat thing about a TH400 is some of the early TH400's from the mid 60s have a torque converter that can change pitches. two different stalls with a push of a button. there are some aftermarkets making torque converters and kits for this. all you need is a pump and stator support from one of these early 400s and put it in. one mode you could have nice 2200 stall, flip the switch all the sudden about 3600 stall.
