GoneDragRacing.com

Just curious what you guys think....

I am planning on running a THM-350 in my camaro...3200 pounds, 4.10 rear, 3500 converter that has been worked on a litle (3800 or so) and 600HP small block.

I had a racing trans builder go through it 5 years ago, never been used....he said without spending a ridiculous amount of money there isn't much to do to it....he put a hardened input shaft in it, and a heavy duty sprag.

What kind of power do you think it can ahndle before it grenades and I step up to a THM-400?

Depends seen guys spend a whole bunch of money on the th350 and have them blow apart and others not a dime and last forever. The th400 is a way better trans and can handle more power for less dollars.

The drum is the weak link in a TH350. If you step up to the billet drum they can handle alotta power but the TH400 will do the job cheaper like Rob said. I've seen TH400's with nothing more than a basic race build take 1100 horsepower in a 3550 lb car goin 8's.

i'm using a 350 behind a 468 with 4.10's and dragradials ,10 4500 stall.Just manual valve body and red clutches.So far its been ok.I see issues this year with it.I can't push my luck another year with out spending some cash on it.

I always thought 400's cost some hp to use.Maybe its an old rumor.I was looking into a jw trans.

TH400's do take more power to turn. it's a give and take thing. Lose a lil power for longevity or spend a lil more for more power and longevity

nicely said jay hear hear!!!!

Baztek went 9.70's with a Trans Specialties foot brake th350 in his Regal, put a load of passes on it then sold it to my customer without a rebuild and it is still holding up going 11.30's in a 3450lb sbc Cutlass.

jays64II wrote:TH400's do take more power to turn. it's a give and take thing. Lose a lil power for longevity or spend a lil more for more power and longevity

personally i think the 400 using hp is part myth!

heres why.

back when I 1st starting racing the syclone i had a 700r4 in it (very similar to a thm350 but with overdrive)

trans was not slipping, but one night driving home it sounded like somebody dropped loose nuts and bolts into a meat grinder! The echoeing off the wall on 561 at the car storage place made me think i was going to be walking soon. anyway made it to the shop, didnt shut it off but put it on the lift b4 going home in my beater (long gone).

anyway next day i found bellhousing was cracked off, or held on by exactly 1 inch. lol

so i put a rossler thm400 in it.

I then went out with no other changes and began running the exact same times.

perhaps rossler makes some changes to limit power robbing effects but i saw no power robbing when i made the switch. btw i had em put an ultrabell on the front if it. lol

ed

Ed , i agree , my buddy swapped his th350 for a th400 in his s10 and it lost nothing , et , mph and 60' all stayed the same

a stock 400 takes alot more power to turn due to reciprocating weight ,turning tq. and thrust . you can lighten up a 400 and some fly weight tricks and get to what a stock 350 has . the 350 needs a drum /sprag upgrade and input shaft to handle abuse like a stock 400 can . weight and lack of rear gear is what kills 350"s .just like a stock built 176 glide is beter than a 350 and in some cases faster . the same goes 400-350 . you gotta compair apples to apples. can you run a worked glide ? or a worked 350 ? then ya wont need to changes crossmembers and drive shafts . a turbo 350 with no decell and a good drum/sprag will keep ya happy along time at 600 h/p and 3000 lbs

Just run it, if it breaks it breaks. I personally think it will be fine...Back in 2002-2003 my father ran 10.70's in his then ~3100lb Monte SS...358" SBC, 32x14's, 4.88's, footbraked. It had a nothing special TH350 in it, with a manual valve body, and a basic performance rebuild. The guy who built it used I believe it was the sprag from a 700R4 (but I'm not sure, I was only 12 at the time). What kills a TH350 is 1-2 shift in the burnout...Leave it in second, or shift 2-3 in the burnout. The tranny was put in the car in 2001, swapped into my brothers car in 2004, and was pulled out in 2006. It's still good today, even shifting 1-2-3 in the burnout before we knew any better.

SmallBlockNova wrote:Just run it, if it breaks it breaks. .

Its thinking like that, that makes us guys sit in the lanes all night due to someone spilling shit all over the track. If something breaks due to negligence that I think thats rather f-d up. Mistakes a mistake but if you have a good idea it might not make it then don't ruin everyone elses night.