700R4 conversion to 72 K5 Blazer

[origcst72blazer]

I'm thinking about swapping out the TH350 Transmission for the 700R4 Overdrive transmission. I use my K5 for long roads trips and I think having an extra gear will help will gas mileage and life of the motor.

Before I endure into this project and get in over my head. What are some of the modifications I would need to make sure it fits properly?

Any insight or advice is appreciated.

Thanks,
Mike

 

[AJs72K5]

I'm thinking about swapping out the TH350 Transmission for the 700R4 Overdrive transmission. I use my K5 for long roads trips and I think having an extra gear will help will gas mileage and life of the motor.

Before I endure into this project and get in over my head. What are some of the modifications I would need to make sure it fits properly?

Any insight or advice is appreciated.

Thanks,
Mike

Search is your friend. Several of us have done it. Do you plan on keeping the 205? Whole different install if you plan on running the 205. I opted for a 241 for simplicity sake. But that also creates its own todo list.

Transfer case aside.... At a bare minimum, the tranny crossmember will have to be moved back 1.5" - 2". You'll likely need new front and rear drive shafts. Carb throttle bracket will have to be modified for proper TV cable geometry. Exhaust tubes may need to be modified.

All in all, a fairly easy install. In addition to the overdrive, you also get the deeper 1st gear for better jump off the line.

 

[Greg Ducato]

If you are keeping the 205 you will need a custom output shaft for the 700R4 or a spacer block to use between the 700 and 205 to compensate for shaft length differences. As has been mentioned, crossmember will need to be moved, driveshafts reworked and shifter for TC modified for new location. Trans column shifter can be used with minor mods, cooler lines will work with slight bending, tv cable linkage will depend on manifold and carb and you will need 12 volts run to the trans from and ignition source to power lockup control (preferable through a later model brake switch) Not too bad a conversion and certainly rewarding for the benefits of the 700.