FocusGhia

I'm just getting to the time (in the next 2 weeks or so) when I am going to have to order a new tranny.

The plan for the car is to have a new 383 built with around 500hp and similar torque numbers.
BUT
I may be able to stretch to getting an ATI-Procharged 383 with the aim to get around 700 crank hp and a lot of torque (well over 500lb/ft I would imagine, maybe 600?).

So I am ordering the tranny with this new engine in mind.
I will then do the same with ordering a new rear end.

Question is, can a TH700R4 handle that sort of engine?
The car will be mostly street driven, with a trip to the strip once a month for maybe 10 runs at a time.
I plan on running drag radials at the strip at least, possibly full slicks but I realise they would put a big strain on the tranny (rear end will be Chevy 12 bolt or Ford 9" so that's not a concern).


How practical is this proposition?
I MUST have an overdrive tranny due to fuel consumption considerations.


QUESTIONS:

1) If over 500hp how much hp and what torque numbers and what tyres do you use at the strip?

2) Are there people on here running 700hp with a 700R4?

2) Who built it and how much?

3) How does it drive on the street?

4) How reliable has it been?



I don't want to go down the wrong road.
If 700hp on a TH700 isn't possible then I'll just go all motor and stick to 500 or so hp.

BaddAzzRS

It is possible to make a 700r4 as reliable at 700 hp as say a TH 350 or 400. In a street car that sees occassional trips to the track you shouldn't have any more issues than you would with any other trans. However it is abit more costly to build a 700r4 to take this level of abuse. Heres an example of a 700r4 built for the application your suggesting http://www.transmissioncenter.net/700megaraptor.htm. Im not suggesting you have to buy this trans from them though you could. If you use the parts list as guide Im sure you could find a local shop to build this trans alittle cheaper. I know a few guys running 700's built this way behind 383's and 415 SBC's pushing the 700HP limit on nitrous and they survive. I had this exact trans built for 1300.00.

FocusGhia

I was considering this one.
The site tells me that using a supercharger lowers the power handling rating.
Why is that?
Surely 700hp and 700lb/ft of torque coming off the engine is just that regardless of how it's being produced?

I was considering the Probuilt one but the power ratings don't go up as high...

Pro Built Automatics

Call me. and I will explain the details about this, and why I can be of help. 800 7763288 anytime after 12 noon PST.

FocusGhia

Will do.

I make that about 8pm London time...

88IROC350TPI

Not to start a war here but I dont understand why people are willing to spend $2000+ on a 700R4 behind big-HP cars all for what? to get better gas milage? Think about it... Lets say you were to buy that "Mega Raptor" for $2300, now you gotta good trans better get a good converter... $800 for that. Now if my math skills are good you have $3100 into your transmission.

Now, you get a junkyard TH350 for $50. You take it to your local reputable trans builder and get it rebuilt with nice parts for $400 (or less). Now you go over to ATI and buy a top-of-the-line $700 converter. You now have $1150 into a TH350.

Ok, now you have $1950 in your pocket. Lets say you drive the car 2 times a week around town or to the track (I doubt you'd drive a 700HP car daily) and spend $35 a week on gas. After one year you'll have spent less than the $1950 you woulda spent "saving gas" by forking out the extra money and using the 700R4. And in the end, your trans would be STRONGER, cheaper, AND better for drag-strip usage.

In the long run you'll be better off with a TH350 in my opinion... Think about it, do you really think the price tag is worth the extra gear?

xpndbl3

iTrader: (5)

chris718

feel free to visit our website.see url below.we ship bi monthly to england.all 700r4s are pre tested in a vehicle prior to shipping so you dont get any surprises.we also build a gmaod hybrid which is a four speed gm overdrive that has been tested in efi renegade cars making over 900 horsepower,there is a picorial of it on our site on the homepage called "gmaod hybrid transmission"when thwe 2004r and 700r4 run out of teeth this thing barely breaks a sweat .has 2 different gear ratiops to better match it to the vehicles torque curve,sfi bellhousing,and internal transbrake if desired.

FocusGhia

First off, in the UK I can't just go to a junkyard and get a TH350. American cars are a vey rare sight over here.
Secondly, I don't want a TH350. For two reasons:

1) The car is meant to have a TH700 and I am trying to go as quick as I reasonably can without altering certain aspects of the car. eg the block must originally be a 350 (thus why I am not going 502 Ramjet for example)

2) The tranny must be a 4 speed (ideally TH700) as gas over here costs avout 3.5 times as much as it does over in the US. So your $35 a week on gas becomes $122. And as I can't buy a tranny form a junkyard for 50 bucks and shops over hre charge a fortune for this sort of work (which is because as I say american cars and thus tranny's are rare over here) I don't have $1900 to use on gas.

I've been thinking about this for the past 12 months and I've done many sums on it and this is a beter way to go for me in the long run and means I can stay true to the4 cars original spec, just "uprated".
If it comes to money the cheapoest thing for me to do would be to sell the stock car which is worth about $8,500 over here and buy a 1996 Saleen S281 supercharged Stang which is selling for $17,000 over here at the moment because the new tranny, rear end, engine, brakes etc etc is gonna cost way more than that.

But it's not about the money, it's about having what I want.

(I do see your point however and it is a fair argument).