200R4 or 700R4

Q: 200R4 or 700R4

I just purchased a 1968 firebird convertible with a 428 from a 1969 grand prix SJ and a Turbo 400. I am considering replacing my Turbo 400 with either a 200R4 or a 700R4. Any advice/suggestions would be greatly appreciated. Obviously, the car was not original/numbers matching to begin with so I hope I’m not offending any purists out there.

Thanks.

A: A couple of things to consider when making your choice:

2004r comes in a bolt pattern that will attach directly to the block and is almost identical in length to a 400TH. This makes the install simple with a 400TH trans cross member. It is considered weaker than the 700r4. If you pull a 2004r out of a Buick Gran National or Monte Carlo SS you’ll get a stronger unit.

The 700r4 is a stronger unit but will not hold up if you plan on drag racing. Either unit can be reworked to make them bullet proof if you have the bucks. The 700r4 will require an adapter ($40) to attach to the Pontiac block and you’ll have to move your transmission back on the frame about two inches. In both cases you’ll have to have your drive shaft shortened ($30).

The TV cable is tricky to get right. Thee are companies that sell TV brackets to mount to an intake but not sure if one is available for Pontiac (would be interested to hear from some one on this). I made the one for my buddy’s car. It holds both the TV cable and the throttle bracket but I have a Mig.

You’ll need a kit to convert the trans to a non-computer controlled unit. I recommend a company called T.P.I. Tech (1-203-599-0382). They have a conversion kit for about $70 and it works great (no switches to flip to go into or downshift out of O.D.).

You can use a stock shifter but you’ll need to purchase a decent kit ($60). The trans yoke from a 350TH will fit directly into a 700r4 (not sure about the 2004r) If your car originally came with a 400TH or you have a rear end from a car that did, it has a large yoke (make sure you have the correct trans yoke).

Over all, it’s not that expensive to do and the way these big cube motors suck the gas, your pay-back is pretty quick if you drive a lot. I’m planning on installing one behind my 400 when it starts to go back together. I’ve install a 700r4 in my buddy’s 1968 Camaro and it works great (300hp and 24 mpg highway on a 3.4:1 gear). Good Luck.

A: The turbo 200 is not a particularly strong tranny, the turbo 700 is, if you get a post ’86 version. The 700 is longer, so you will have to do driveshaft and crossmember mods to get it to fit, and possibly the floor pan. Get the yoke with the tranny.

A: I have a 1969 Ragtop with the same package and I’m runing a 3.08 posi rearend. Why would you want to convert to a 2004R? My car has enough torque to smoke the tires from here to kingdom come and it runs great on the hiway (13.7 in the 1/4). Though I did add a Holeshot 2000 torque converter to it. I would’nt mess with a good thing. That’s my 2 cents worth.

A: The 700R4 is the stronger of the two transmissions,however it is not anywhere near as strong as a turbo 400,particularly in stock form.This also applies to the 200R4. You should not even think of using either model without having it rebuilt & beefed up as much as possible.If you are real lucky or diligent you may be able to find a 700R4 with the “dual-pattern” case (ie-it has the chev & buick/olds/pontiac bellhousing pattern) I don’t know how rare they are but they do exist. As mentioned before, you also have to deal with shifter, driveshaft length, X-member etc. I would also install an external trans cooler to increase reliability.

A: No 700r4 came with the B-O-P pattern, only the Chevrolet pattern. The Monte Carlo SS only came with a 305, therefore only a 200 4r. Your best bet for a 700r4 is a late model Camaro/Firebird. As to “why” ans someone asked… you get a lower first gear and overdrive all in the same package. No you cannot drag race a stock 700r4 like you can a 400TH but most who build their cars for drag racing don’t do much highway cruising. I like to drive my convertible with the top down to a little town about two hours away. At 24 mpg versus 16 mpg it doesn’t take long to pay for the conversion. And with the lower first gear you can still burn the tread off of the tires if you feel like it.

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