GM 200R4 or 700R4 surviving behind blower motor?

[kick_the_reverb]

Hi, this is a question for guys who have some experience with the GM overdrive trannies behind powerful engines.
Being that my vehicle (Dodge A100) has a 90" wheel base, I can't plan on using a Mopar overdrive tranny behind my SBM (they are way too long). I just scored a TCI adapter set up that can mount a GM tranny to a SBM.
I have been looking online and it seems that the 200R4 or possible the 700R4 are short enough to fit, and there are some companies that offer beefed up versions. Problem is, the plan for my serious engine is a 426 SBM stroker with a roots blower. The capacity I see in most places is "up to 650HP" for the toughest most expensive set ups. Perhaps more at Art Carr, but those are super expensive. You'd think that with a roots blower the torque would be so much that the tranny could be in danger. Granted this will not be a race car, but if I will be going with this combo it will have to survive some occasional runs down the strip, plus a lot of street driving.
Anyone have real first hand experience with these transmissions behind high torque engines? Any reccomended vendors? I tend to trust user experience more than advertizing and magazine articles...
Thanks,
Ran

[squirrel]

Re: GM 200R4 or 700R4 surviving behind blower motor?

Why do you want overdrive? Just curious....I have a blown big block in my 55 backed by a TH400, and it seems that when I put enough gear in it that it's revving too high on the highway, then I end up just smoking the tires on the street. And I ran quicker in the 1/4 with 3.25s than I have with 3.70s (although there are several other factors involved that caused that, I think)

Street blower motors make gobs of torque over the whole rpm band, so you don't need much gear behind it.

[min301]

Re: GM 200R4 or 700R4 surviving behind blower motor?

Hi, this is a question for guys who have some experience with the GM overdrive trannies behind powerful engines.
Being that my vehicle (Dodge A100) has a 90" wheel base, I can't plan on using a Mopar overdrive tranny behind my SBM (they are way too long). I just scored a TCI adapter set up that can mount a GM tranny to a SBM.
I have been looking online and it seems that the 200R4 or possible the 700R4 are short enough to fit, and there are some companies that offer beefed up versions. Problem is, the plan for my serious engine is a 426 SBM stroker with a roots blower. The capacity I see in most places is "up to 650HP" for the toughest most expensive set ups. Perhaps more at Art Carr, but those are super expensive. You'd think that with a roots blower the torque would be so much that the tranny could be in danger. Granted this will not be a race car, but if I will be going with this combo it will have to survive some occasional runs down the strip, plus a lot of street driving.
Anyone have real first hand experience with these transmissions behind high torque engines? Any reccomended vendors? I tend to trust user experience more than advertizing and magazine articles...
Thanks,
Ran

PM Indyshiftman, he's a tranny guy here, and has the answers you seek.
Brian Rock(Goat Racer-here) has a 200R4 as well, in his 65 GTO, so he should be useful too.

[BigBlockMopar]

Re: GM 200R4 or 700R4 surviving behind blower motor?

I've seen first hand with a friend who has a '86 Camaro with a serious 350, and later a 383, who kept on having his 700R4 fixed and improved numerous of times.

Now, I have no doubt there's way more experience in the US modifying and making such a tranny live behind a powerfull engine then overhere in the Netherlands, but personally I would never put anything like that behind a blown engine.

[jays67]

Re: GM 200R4 or 700R4 surviving behind blower motor?

we ran a 200r4 behind my buddys 406 in his monte it lasted a few weeks now has a built turbo 350 and been in there few years with a heavy foot

[70.5CAMARO]

Re: GM 200R4 or 700R4 surviving behind blower motor?

if i had to pick one of the two i would go with the 200r just for the fact that it is fully mechanical, the weakest part of the 700r is the electronics in it. i have seen 200r take 650+ hp with a 3000 stall. and last for quite a while, these guys were taking it out every 6 months cause something else would break so it always had new fluid and wasnt beat on "too" hard

[TheSilverBuick]

Re: GM 200R4 or 700R4 surviving behind blower motor?

if i had to pick one of the two i would go with the 200r just for the fact that it is fully mechanical, the weakest part of the 700r is the electronics in it. i have seen 200r take 650+ hp with a 3000 stall. and last for quite a while, these guys were taking it out every 6 months cause something else would break so it always had new fluid and wasnt beat on "too" hard

Purely mechanical? The 700r4 and 200r4 have the same electronics, namely to lock the converter up.

[kick_the_reverb]

Re: GM 200R4 or 700R4 surviving behind blower motor?

Thanks for the input so far guys.
I'm the first guy to doubt the strength of a GM overdrive as opposed to a Mopar TF727. I was thinking that with the stroker and the blower I might be able to just use highway gears and the 727. I see two possible problems with that - no new gears made for my rear end that are less than 3.55:1, so having to find used gears is somewhat of a pain. Second, my concern that until I get the 426 (long term project), I will be driving with a low compression 318 and the blower. I know the blower makes torque under power, but what about normal driving? Could be a dog. I do notice that with the 3.55 gears I have now the van defintely can't keep up with highway traffic in So-Cal. I will be changing to 28" tires as a first remedy, but there's something about the "have your cake and eat it" side of an overdrive trans that appeals to me on a vehicle that will get driven a lot. Of course if a beefy enough GM overdrive costs $3k, that makes it far less appealing...I know which Mopar Torque Flite builders I can trust, but I have no idea about the GM guys, and it seems some shops specialize in those transmissions.
I don't want to have this scenerio happen:
Pay a lot of bucks for say a beefy 200R4. Drive it with the blown 318. Put the blown 426 in front of it later - oops, transmission can't handle it, back to TF727.
Thanks for the input so far...I'll also PM Indyshiftman, see if he can offer an opinion.
Ran

[squirrel]

Re: GM 200R4 or 700R4 surviving behind blower motor?

The blown 318 will do just fine, blowers really wake up weak engines. Sometimes a bit too much, so try not to blow it up. Roots blowers have a nice flat boost curve. Should be able to pull mild gears just fine.

If it's a 9" then you should be able to find 3.23 gears for it easily, and I'd trust old used original Mopar gears more than I'd trust new gears, the way they make things these days.

[min301]

Re: GM 200R4 or 700R4 surviving behind blower motor?

You could always throw a used G/V unit at it. Those are pretty strong, from what I hear.

[kick_the_reverb]

Re: GM 200R4 or 700R4 surviving behind blower motor?

If it's a 9" then you should be able to find 3.23 gears for it easily, and I'd trust old used original Mopar gears more than I'd trust new gears, the way they make things these days.

It's a Mopar 8 3/4", so you can still find used gears from time to time. So the plan so far is heads then blower then see if highway gears make it play nice in highway/street. If that works, the OD tranny would not be needed.
Thanks
Ran

[kick_the_reverb]

Re: GM 200R4 or 700R4 surviving behind blower motor?

You could always throw a used G/V unit at it. Those are pretty strong, from what I hear.

Nope, not on an A100. They have a 90" wheel base so they have to use a special shortened version of the TF727 (which is also hung from the top, BTW), and a really short driveshaft. Any change in the length of the transmission (like a GV unit or a Mopar 518 for example) would make the U-Joint angles too severe, which does not work on a street vehicle. That's why I was considering the GM OD transmissions which are short.
Anyway, I'll see how this plays out, but I'd still like to hear pinions on shops that can build a stout 200R4.
Ran

[squirrel]

Re: GM 200R4 or 700R4 surviving behind blower motor?

If it's a 9"

I meant 8-3/4" doh! just had a brain fart when I typed.

I've run 2.75, 3.0, 3.25, and 3.70 gears in my 55 with the blower. They all work fine. The car was a dog with 2.75s with an unblown 454, though.

[RyanWalker]

Re: GM 200R4 or 700R4 surviving behind blower motor?

I believe Brian Rock who has a street driven 10 second 65 gto on this forum, runs a 200R4 ( that's been beefed up a bit ). I believe it has friendlier highway ratio's and is lighter overall vs. the 700R4. I'm sure the 200R4 can be beefed up quite a bit if need be.

[CTX-SLPR]

Re: GM 200R4 or 700R4 surviving behind blower motor?

Critical bit for you, TH700R4 is longer than a TH400, Th200-4R is the same length as a Powerglide.