convert to a 400

[oldtimer]

Can someone direct me to information required to convert from a 200 4 R to a Turbo 400

I suspect I'll need to change the converter, crossmember, rear yoke and driveshaft length. What about throttle pressure and shifter .... what else ... am I on the right track ?

 

[turbodave231]

Hey Oldtimer!

To convert to a 400 is easy in a GN. You can use the stock
X-member, the stock trans mount (need to slot one hole) and the stock driveshaft. All you need is a short 400 yoke. If the yoke is too long is will bottom in the trans.

Piece of cake!

 

[85HOT-T]

Turbo dave this sounds too easy. I too was looking into a 400 swap and if that is all, why don't more people do it. Turbo 400 will take down 3 or 4 200's before even sweating.

 

[chris718]

hey dave,how come when i say that everyone disagrees?weve just done 2 in the past week,

 

[oldtimer]

Originally posted by chris718
hey dave,how come when i say that everyone disagrees?weve just done 2 in the past week,

Ok Chris,

tell me the facts. My search came up with seemingly contradictory information.

shorten driveshaft 1/2 inch ... no need to shorten driveshaft

modify stock mount .... use Paul Ferry's modified mount

The one thing I know for certain is that I'd have to use the TH400 yolk


ALS0, how do I deal with throttle pressure ?

 

[chris718]

follow turbo daves instructions

 

[oldtimer]

Originally posted by chris718
follow turbo daves instructions

And what about the throttle pressure ?

 

[oldtimer]

Originally posted by turbodave231
Hey Oldtimer!

To convert to a 400 is easy in a GN. You can use the stock
X-member, the stock trans mount (need to slot one hole) and the stock driveshaft. All you need is a short 400 yoke. If the yoke is too long is will bottom in the trans.

Piece of cake!

Turbodave231 ...... and Chris !

Thanks a lot.

How do you deal with the throttle pressure issue ?

 

[chris718]

if you arent running a brake youll need a mechanical modulator as the 400 cant use a boost signal or positive pressure in the intake manifold to shift the car very well if your running a brake the pressure is fixed.

 

[oldtimer]

Originally posted by chris718
if you arent running a brake youll need a mechanical modulator as the 400 cant use a boost signal or positive pressure in the intake manifold to shift the car very well if your running a brake the pressure is fixed.

Thanks Chris

 

[ijames]

Chris, I thought you could use a vacuum line from the throttle body, to a check valve and then a tee with a small leak on the sidearm, to control the vacuum modulator? That way all boost just looks like wot on a n/a setup.

 

[oldtimer]

Originally posted by turbodave231
Hey Oldtimer!

To convert to a 400 is easy in a GN. You can use the stock
X-member, the stock trans mount (need to slot one hole) and the stock driveshaft. All you need is a short 400 yoke. If the yoke is too long is will bottom in the trans.

Piece of cake!

Turbodave231

Is there a specific vehicle that uses this short yoke ?

Is there a part number to ensure I get the correct one ?

 

[J Banning]

Bump...

I'm also interested as well.