TH350 Tranny is it going to be a problem when?????

[1979blkchevy]

Hello everyone just wanted your advice or your 2 cents about th350 trannies!! What i was wondering was how much of horse power can you put to them intil something happens to them? The story is I just ordered a 383stroker with 460hp and 480tq to implant in my truck so right now im doing my cooling system over and ect to make sure this motor runs strong and stays cool and ect!! so i got thinking about the tranny if i was going to have to switch to a th400 or a 700??

thanks in advance guys

[old Rusty C10]

it depends on the th350 you buy. I have little faith in the generic rebuilds but if you get one thats modified, they have better life expectancy and they become almost bulletproof. Id recommend that you go to TCI who built me a trans years ago that I beat on for years in my el camino .It had a modified motor in it that was bored .30 over etc.
Lately i have a guy who builds transmissions for me who are dern good but hes in Elmont long island and is too far for you to deal with as he is a mom and pop shop

[LONGHAIR]

A lot of this has to do with traction. If you don't "hook it up" the transmission never really "sees" the amount of power you really put into it.

[cableguy0]

the 700r4 is not a good option it will break even if you spend 3 grand on it. the th350 with a heavy sprag and drum assembly, good clutches and steels and a shift kit should hold it no problem. the th400 will also hold the horsepower no problem and the same upgrades would end up being performed. in the end the th400 is stronger but eats more hp than the th350. the important thing is to get a good torque converter.

[1979blkchevy]

thanks alot for the replies you guys are a big help

[1979blkchevy]

Originally Posted by cableguy0

the 700r4 is not a good option it will break even if you spend 3 grand on it. the th350 with a heavy sprag and drum assembly, good clutches and steels and a shift kit should hold it no problem. the th400 will also hold the horsepower no problem and the same upgrades would end up being performed. in the end the th400 is stronger but eats more hp than the th350. the important thing is to get a good torque converter.

any suggestions on where to buy the interals for theses th350s?? TCI?

[85Bowtie]

I don't know, 460HP and 480 ft/lbs sounds like TH400 territory to me if your looking for longevity.

[thrtsxchambers]

I have a th350 in my 83 that has been rebuilt and beefed up to handle 450hp. I ripped it apart playing around one day and talked to the shop about my plan for a 383 in the future. He rebuilt it with tci parts and a shift kit and it works well. I still have the 305 in it for now but he told me to stay with the th350 if I plan running it hard (which I do) the 350 will handle the abuse with the 383(but he is still bugging me to drop in a ls1). My tranny is now equivilant to the tci "street fighter".

[cableguy0]

Any of the large aftermarket transmission companies have the parts. I personally used the tci sprag and drum assembly and it hasnt handled straight up torture for somewhere near 40k miles. I'm also running a tci converter with anti balooning plate. You will see that as a reccomended feature for any engine using nitrous but its a good idea in a heavy truck with high hp.

[1979blkchevy]

Originally Posted by thrtsxchambers

I have a th350 in my 83 that has been rebuilt and beefed up to handle 450hp. I ripped it apart playing around one day and talked to the shop about my plan for a 383 in the future. He rebuilt it with tci parts and a shift kit and it works well. I still have the 305 in it for now but he told me to stay with the th350 if I plan running it hard (which I do) the 350 will handle the abuse with the 383(but he is still bugging me to drop in a ls1). My tranny is now equivilant to the tci "street fighter".

wow that is awsome so tci is the way to go!!

[thrtsxchambers]

If you have too much money you can get a bowler but sit down before you look up the cost. TCI has good prices, it was a cheaper to rebiuld and beef up my tranny than it was to buy from tci.

[silvereagle07]

You can also look here. I may get one of their overdrives. http://www.gearstar.net/

[primer]

I'm not wanting to get too far off track, but if your running all this in a 4x4 you may want to pay close attention to you t-case. I've run a small motor in front of a weak tranny and I still blew a chain out of a np203 (makes for a lot of really ugly noises). In defense of the 203, I was driving in a way that something had to give it up.

[1979blkchevy]

Originally Posted by primer

I'm not wanting to get too far off track, but if your running all this in a 4x4 you may want to pay close attention to you t-case. I've run a small motor in front of a weak tranny and I still blew a chain out of a np203 (makes for a lot of really ugly noises). In defense of the 203, I was driving in a way that something had to give it up.

so you think i should do something with the tcase it makes sence!!!

[primer]

It depends on what t-case you have now, but if I were you I'd be looking for and np205. I have a 203 in my step side and it has held up behind a 383 and th350 but I don't like having to worry about it every time I put my truck in a bind. After I get my burb built the truck's getting torn down and a 205 will replace the 203.

[MR .T]

My last hotrod s10 had a th350 and it worked great with a b&m kit and 3000 stall but I ran a cooler on it. THe bellhousing cracked all the way around and broke but the internals were fine.

[1979blkchevy]

Originally Posted by MR .T

My last hotrod s10 had a th350 and it worked great with a b&m kit and 3000 stall but I ran a cooler on it. THe bellhousing cracked all the way around and broke but the internals were fine.

so you were replacing that bell housing

[spinem]

th350 was made for up to 350hp brand new, a tired old trans will slip, get hot and boom.
th400 was like 425 or 500hp i dont remember. just remember, a good builder can make it bullet proof.

700r4+lock up converter built strong will be plenty.

Ive thrown 10,000 miles at an old th350 with 330hp, burnouts, racing, the works, it lever let go. so its a toss up. me,? id sell ur 350, buy a 400 and bullet proof it.

[MR .T]

Originally Posted by 1979blkchevy

so you were replacing that bell housing

Nope its all 1 casting, I still have it in the garage was planning on taking it apart.

[1979blkchevy]

Originally Posted by spinem

th350 was made for up to 350hp brand new, a tired old trans will slip, get hot and boom.
th400 was like 425 or 500hp i dont remember. just remember, a good builder can make it bullet proof.

700r4+lock up converter built strong will be plenty.

Ive thrown 10,000 miles at an old th350 with 330hp, burnouts, racing, the works, it lever let go. so its a toss up. me,? id sell ur 350, buy a 400 and bullet proof it.

your right bout this i was reading an ad from 4x4 wheeling and they did a crazy job in building a np205 bullet proof! But then again they probaly used some expensive parts but i was always told you get what you pay for but i was really thinking about buying a used one and then just tearing it apart and then building it bullet proof or having someoone build it for me if i didnt have the time!! Or do you think i should just buy one already built any opions on this??

[1979blkchevy]

Originally Posted by spinem

th350 was made for up to 350hp brand new, a tired old trans will slip, get hot and boom.
th400 was like 425 or 500hp i dont remember. just remember, a good builder can make it bullet proof.

700r4+lock up converter built strong will be plenty.

Ive thrown 10,000 miles at an old th350 with 330hp, burnouts, racing, the works, it lever let go. so its a toss up. me,? id sell ur 350, buy a 400 and bullet proof it.

whats the difference in the gearing in the 400 and 350 any major differences between them????

[1979blkchevy]

Originally Posted by MR .T

Nope its all 1 casting, I still have it in the garage was planning on taking it apart.

casting is some tuff stuff

[cableguy0]

the 350 & 400 are almost identical in gearing. the th400 does however eat a little more horsepower but its a lot stronger in the first place. in my first post i didnt realize the truck was a 4x4. with that hp and big tires etc i would lean more toward a th400 with the same upgrades i mentioned for the th350. If you plan to beat on this thing you best bet would be to spend the money up front rather than waiting for stuff to break and replacing it as you go. its usually cheaper to spend more in the first place. i vote th400/np205 for a bulletproof driveline

[primer]

The np205 can be built to an extreme, but in my personal opinion a stock 205 won't be your weak link. The 205 is a cast housing and gear drive... it's a whole lot of solid metal. I have seen many u-joints, axle shafts, drivelines and those types of things fail due to the fact that they are weaker than the 205. When my stepside is finished I plan on having a sm465/205 14 bolt and 8 lug dana 44 and I intend to upgrade all my u joints with the exception of the ones closest to the diffs. This may sound strange but the idea is to build a running gear that can take the 383 but have a weak link that is easily replaced, and will cause the least amount of damage when it fails. Keep in mind that we probably drive our trucks differently, I expect mine to fail.

[1979blkchevy]

Originally Posted by primer

The np205 can be built to an extreme, but in my personal opinion a stock 205 won't be your weak link. The 205 is a cast housing and gear drive... it's a whole lot of solid metal. I have seen many u-joints, axle shafts, drivelines and those types of things fail due to the fact that they are weaker than the 205. When my stepside is finished I plan on having a sm465/205 14 bolt and 8 lug dana 44 and I intend to upgrade all my u joints with the exception of the ones closest to the diffs. This may sound strange but the idea is to build a running gear that can take the 383 but have a weak link that is easily replaced, and will cause the least amount of damage when it fails. Keep in mind that we probably drive our trucks differently, I expect mine to fail.

now with a np205 will i have to change the length of any of the drive shafts?