turbo 400 or rebuild again in a year

[makovai]

Thats what the tranny guys are telling me. because i have 4:56 gears I'm doing about 3K rpm on the freeway at 60mph. The tranny guys are saying the th350 cant handle those kinda of rpm's, and that if i dont go to a th400 I'll be rebuilding the tranny again very soon.

I got the tranny out last night (forward pump is shot) and now im trying to decide if i want to step up and goto the 400. Its alot more money, but it'll be a lot beefy'er tranny.

[JMac11]

400 More money and consumes more of your HP. In drag racing they never seemed to be as tough as everyone thinks.

350 would be my choice if avoiding the 700R4. Can be iffy, depends on the builder and the core you start with.

[70rs/ss]

Well, the 400 is a strong as its supposed to be, and that also depends on if Bubba builds it or a trained technician. That aside, the 350 is strong, but the 400 is stronger. I am running a 350 behing my BBC in my 67 and it hangs (and I don't baby it at all!) I also have a 700r4 behind another BBC (again, no babying) I guess I'd see what the step up to the 400 would cost vs the cost of the second rebuilt, and I'll bet having the 350 built again is cheaper than buying the 400, building the 400, buying another 205, rebuilding it, vs rebuilding the 350 a second time. I really doubt the high r's kill it, but more likely the heat and if you buy a mongo tranny cooler it will last. Heck you can even buy coolers w/thier own fan. explore your options and get a second and even a third opinion from different shops.

[makovai]

Hmmm, I'm kinda taking this as the 350 will hold up if its done right and the 400 is not worht the extra $$$$$$$$

[smokekiki]

I am running a 350 behind a BB in my suburban.I am turning 3000rpm at cruise speeds.It has about 15k in it.The fluid looks new.Change it and the filter every 12k miles.I am also running a B&M plate style cooler.No heat issues,even pulling a trailer with my blazer on it.

[smokekiki]

Originally Posted by makovai

Hmmm, I'm kinda taking this as the 350 will hold up if its done right and the 400 is not worht the extra $$$$$$$$

You would need a big bearing 205,or machine yours for the bigger bearing ans input shaft.Also would need the adapter for a 400,plus the 400.A good cooler will cost $50-$100 new,around $200 for one with a fan.Around $35-65 for a Temp gauges.

[qksilver]

Many options, but a built 350 will hold together. I had a 78 SWB 1/2 with a 406 tunnel ram, 488 gears and 48 inch tires. I bought it beat and continued to beat on it. The P/O had ATI trans out of Baltimore MD build it, he had it a year and I had it for a year until MD changed the lift laws.
It did have a maual reverse valve body ........
Build it right, and like Mike says a big cooler , I am guess it's for the Blazer in your Avitar.
More weight, towing a 400 will do better in the long run, one 400, how many 350's?

[vtblazer]

I'd have to agree with the rest of the guys here, a 'correctly' built th-350 should be plenty strong/tough and survive the revs.

I'm also running a built th-350 behing my 396 w/4:11's and it seems perfectly happy doing so.

I've towed lots of trucks on my trailer for hours @ a time doing highway speeds.

Do some research and I bet you could prove 'em wrong.

[makovai]

in all ohnesty it's not like i blew my tranny up, it just lost the forward pump, so that kinda says it did hold up as far as gears go. There's too many of you saying it'll be ok so i think i'll look at a different tranny shop. Thanks for the opinions guys.

[70rs/ss]

You can buy built trannies from B&M, TCI, etc for like $1000, but even a rebuilt GM 350 with good clutches, deep pan (3 more qrts capacity) etc and the 350 will last.

[Blazerb61]

Build that 350 with corvette clutches I rebuild all my own transmissions and a 350 is a good 1 Just have it built right

[LUV2XCLR8]

No bad ass gear ratio's here, but "GQ" has a built sbc in it w/ 450+ hp
and I know it has very little miles on it but I think it would handle the
stress or the PO would have put something better in it, he spared no
expense on this rig before I got it, so in short I also AGREE w/ above.

[makovai]

Originally Posted by 70rs/ss

You can buy built trannies from B&M, TCI, etc for like $1000, but even a rebuilt GM 350 with good clutches, deep pan (3 more qrts capacity) etc and the 350 will last.

I love that idea, but after putting a 330 hp crate motor in last month my wife is a little bit grumpy about purchases right now. I have to fix this one and she gave me a $400 budjet, thats why im doing the R&R myself.