I have a turbo 400 behind my 69 396 dyno rated 540 HP 560 ftlbs. I have a 373 rear axle and want an overdrive trans. Gearstar out of Akron Ohio is telling me they can build a 700r that will live behind my engine..mainly street use...but it does get hammered occasionally. Most shops are saying it won't live. Does anyone out there have any first hand experience or recomendations. really need that next gear for some fuel economy and highway cruising. Suggestions based on real first hand experince is more valuable than opinion at this point.....I have collected a lot of opinions....mostly uninformed I believe.

The 700r4 will live for awhile.Get a 2004r it will live longer they can be built to handle more power than a 700.The problem with the 700 is shifting under power it shifts slow and is in two gears at the same time.It has to do with the valvebody and trans. case .there is not a solution for it yet as far as I know.About 450hp is max for a 700. Now a 4L60E is the same basic trans. as the 700r4 but is shifted eletrically and doesnt have the shift problems. But you have to buy a controller for it.JMO

Like 67Plum said get a 2004R instead. The 700 also has a wider gear range between the 1-2 shifts and there are just more aftermarket billet parts to build a 2004R. Use a CZ or CQ 2004R core, out of 83-87 Monte Carlo SS, you will definitely want to use a billet forward drum, alto red clutches, performance servo, deep trans pan, etc. Not necessarily cheap, but with the HP/TQ your pushing you can build the trans right from the start or rebuild AGAIN after you tear it up.

Go do some research in the Transmission section on www.turbobuick.com board. Those guys are experts on 2004Rs and are more than willing to answer any questions you may have and provide a list of reputable 2004R transmissions builders. If you have any other questions feel free to PM me as I just purchased a built 2004R and may be able to help you.

I have a 700R4 behind my 454 adn have not had any issues with it. The car put down 330RWHP and 430RWTQ so add the percentage to get the flywheel HP numbers. I enjoy it on the highway but liked the shift characteristics of the TH400 better. I am running 3.31 gears. Runs about 2100 rpm at 70 mph.

Please talk to the "REAL ART CARR" about a built 200 b/c I figure it is worth it in the long run...

pdq67