700R4 question

Discussion in 'The "Juice Box"' started by gscalifornia, Mar 26, 2020 at 9:26 PM.

  1. gscalifornia

    gscalifornia Small blocks rule!!

    Looking for a little guidance. I have a chance to pick up a Monster brand Super Duty 700 R4 with a 1650 stall converter for$1500, ready to run. It’s built to handle 600hp and I’m running a small block that’s well under that. Is this a decent deal to move into an overdrive transmission?

    Assuming I go this route, which adapter plate would be a good choice to bolt it to my 350 block?

    Also thinking this would be a good time to go to a 3.73 rear gear instead of my current 3.23s.

  2. Bens99gtp

    Bens99gtp Well-Known Member

    Keep in mind that the 700 have a very steep 1st gear ratio......over 3. . As where 400 and 350 are closer to 2.5. So adding more gear will really change things. But should keep you about 2000 at 60mph

    I would want more stall behind either a 350 or bbb than 1600rpm.........I think that would load up hard going into gear
  3. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Hi, yes Ben is right that converter wouldn’t be a good match. I would use a 2500 stall.

    summit racing sells the adapter plate that you would need, or I have a spare one on the shelf lol. It’s $70 new. The spline count is different on the driveshaft so you may as well do a custom driveshaft as the length is different anyways. The cross member needs to be moved on the frame but that’s easy. The TV cable adjustment is the key to longevity with this swap. You need a mod to your Q jet to connect the TV cable. Ken at Everyday Performance can set you up.

    monster has a hit and miss reputation, lots of good reports and some bad reports. If the trans is used I wouldn’t pay over $900.

    The gearing of the 700 would make your 3.23 gear feel like a 4.00 gear when leaving the line! And with a 27” tall tire you should be at 2610 rpm now at 65 mph, but the trans swap would give you 1830 rpm! It would be 2250 rpm at 90 mph!

    if you swapped to the 7004R and did a 4.10 gear it would be 2300 rpm at 65 mph. And it would be enough gearing to launch that car off the line line never before!
  4. Matt69olds

    Matt69olds Well-Known Member

    I have built a couple “monster in a box transmissions”, other than the connivence of everything coming coming in one order, I’m not impressed. I can tell you their customer service absolutely sucks. I built a C6 g or a friend of a friend, and needed some information. I’m not very familiar with the C6, and since this was going behind a very stout 900-plus hp big block ford in a heavy station wagon, a standard overhaul kit wasn’t going to get it done right. Every question was “let me get back to you”, which they never did. Other than the paper and rubber kit, and a few of the clutches, I didn’t use much of the kit. They didn’t have the servo, servo lever, had no information on drums to fit additional clutches, etc. I had to get info and parts from another vender.
  5. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    What cam do you have in your sbb, that would be the biggest determining factor when trying to figure out stall speed needed.

    Is that converter a lockup or non lockup? This is another thing to consider as well.

    I have a very mild cam in my Impala with the sbc 383 that has a 700R4 behind it and I have a 3,000 stall in it that is mis-matched very well, works good at the track and down the highway with the converter locked up! Without it locked though it makes the engine rev about 450 more RPMs when just cruising on the highway or even at 45, good thing that O/D gear knocks the RPM down without being locked, its like an extra gear.

    My car has a 3.07:1 rear gear in it with the 700R4 and first gear is like driving on ice from a dead stop!:eek:(that is with the drag radials aired up to 35 psi and with them cold)

    The 3.07 is about the lowest you should go with a small block to be able to go into O/D @ 45 mph without lugging the engine because the RPM is to low. Depending on car weight, cubic inch displacement and camshaft a 3.07 might not even be enough gear?

    Your 3.23:1 rear gear would be a great ratio with a 700R4, plenty off the line and still a good final drive gear for great fuel economy, especially with a lockup converter. Something you may want to try out before you spend the $$ on changing the rear gear?

    So a factory non-performance converter is usually around 1,200 RPM and a GN or Corvette factory performance converter is around 1,800 RPM, looks like that one is in between the 2 factory ones.

    If you have an TA RV-112 or a TA-212 or even up to a Crower level 3 cam that converter would probably be just fine, anything bigger then you'll probably want a higher stall speed.
  6. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I don't think it's a good buy for you. The 700 gear spread sucks and you have to replace the converter. Couple that with the adapter and driveshaft work and you're in deep. A 2004r will not require any driveshaft modifications.. I'd keep looking. And for your current application a well built stockish 200 will be fine unless your future holds 600+ hp.
  7. gscalifornia

    gscalifornia Small blocks rule!!

    I've been running the TA 290-94H cam and most likely will be running something similar in the new engine.

    I was told the spline count on my T350 driveshaft is the same as the 700R4 and I just have to have it shortened and balanced.

    I've got a set of 29" tall whitewalls that I normally use with the 3.23 rear for long distance driving but they slowed the car down a lot in the 1/4 mile. I was thinking of trying them with the 700R4 to help off the line, I usually drive to the track and "run what I brung."

    This 700R4 was setup with a dash switch for the lock up, I was considering doing the same. My local trans guy that built the T350 I've beat on for 20 years is much more familiar with the 700R4 than the 2004R, the main reason I was considering this.

    Anyone know of any 200R4s available that are ready to bolt in that would work with what I'm doing?
  8. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I normally prefer the 2004R over the 700, I have two Buick’s with this combo. You can likely find a used 200 and pay $1200 for a good rebuild and $350 for a good converter. Plus the driveshaft from the 350 normally works fine. These trans are about 1/4” longer than your 350. Some people shorten the shaft others do not.

    the 700 trans comes with either 30 or 27 (th-350 is 27). So find out which it is.

    call Janis to discus a 2004R:

    Last edited: Mar 27, 2020 at 9:29 AM
    TexasT likes this.
  9. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    With a 200R4 you will want at least a 3.42:1 rear gear ratio with a sbb to be able to shift into O/D without making the engine lug at 45 mph. Again this is dependent on what cam, vehicle weight and engine size but is usually the minimum rear gear ratio you'll see from a vehicle that was built with this trans from the factory.

    A good rule of thumb is that you want a 9.5:1 1st gear multiplication ratio with the typical older overdrive transmissions to be able to shift into Overdrive @ 45 mph.

    2.74(200R4 1st gear ratio) X 3,42(minimum rear gear ratio) = 9.3708:1 which is close enough for the available rear gear ratios out there.

    3.06(700R4 1st gear ratio) X 3.07(minimum rear gear ratio) = 9.3942:1 which again is close enough to 9.5:1.

    Works out pretty good since its how the General geared vehicles with those transmissions from the factory but usually a vehicle with a 700R4 had a 3.08:1 rear gear, the 3.07 is from the older 12 bolt rear end that IIRC was out of production by the time the overdrive transmissions made it to production.
  10. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Being that you drag race this car I would personally look at a 3.73 gear with a 700 and a 4.10 gear with a 200 trans.
  11. Bens99gtp

    Bens99gtp Well-Known Member

    The OD in a 2004r is .67 snd a 700r4 is .7....that's not a huge difference.........but the steeper 1st gear and larger spread is something to consider
  12. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    In my turbo 350 Skylark I run a 4.56 gear, 32x18.5-15 tires, billet 2004R trans, 3800 stall converter with lockup, and it turns 2550 RPM at 80 MPH.

    in my 75 Regal with a 350 I run a 2.56 gear, 295/50r15, 2004R, 3000 stall, lockup, and it cruises at 1650 RPM at 80 mph and 2500 RPM at 120 mph. It’s more of a highway car, bit I will try it at the track once I add the turbocharger.
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  14. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    WOW, are you building that to run on the salt flats?:cool:

    That's 1.7152:1 final drive gearing!:eek:
  15. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I dunno it cruises good at 140 mph too... replaced the radiator today
  16. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    After the turbo what would that mph be able to be?
  17. Fox's Den

    Fox's Den 22 years of racing the same 355 Buick motor

    With my 2004r I run a 373 gear with a 28" tire 3000 stall with lockup. I am at 2200 rpm at 65 mph Built by Janis Transmission in Akron Ohio, this was done in 2005.
    In my sig you will see the times with a turbo 350 and the 2004r with a 125 shot of nitrous went a little faster with the 200 trans.
    real world
  18. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    im not sure but in my other Skylark that I sold the new owner did 20” wheels, speed rated tires, all performance suspension and when he took me for a test drive we easily hit 170 mph before he let off. It was 4650 RPM at 170 mph . That was a 3.42 gear, 2004R trans, 9:1 buick 350 with the turbos. Was 460 wheel Hp and 450 wheel TQ (at 10 psi) but he turned the boost up between the dyno testing and street testing. I believe he was at 18 psi when he took me for a drive. He had to baby it off the line and part throttle till 60 mph or the 12” wide tires would go up in smoke. 60-170 mph pull was impressive.

    I have this engine and trans back now as he went to a 383 that was 590 HP NA and then he runs twin turbos and it does 920 hp to the crank.
    Last edited: Mar 27, 2020 at 3:26 PM
    300sbb_overkill likes this.
  19. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Nothing wrong with a 700 trans
  20. gscalifornia

    gscalifornia Small blocks rule!!

    Seems like consensus is a 200 4R would be a better choice, just trying to make a good decision

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