I have an 84 z28 with the stock 700r4. I have a th-350-the one WITHOUT a 9 inch tailshaft. I have the bracket to do the conversion. it works. But I need a longer driveshaft, I am going to lengthen my stock one, how much should I tell the shop to do it??? and, what is that vaccuum thingy on the bottom of my th350? do I have to hook something up to it?? and I also have a brand new cable for the th350, any tips on the installation?? THANK YOU!!!

 

The 6" short tailshaft TH350 needs a longer driveshaft. You can lengthen your old one or find one from an 82 with the TH200 transmission or get a 9" tailshaft TH350 that doesn't need a driveshaft swap.

The vacuum modulator is what causes the transmission to upshift. Without it you'll always be in first gear.

The detent cable is for downshifts (passing gear). Apparently there's a tranny swap kit. You can't use the 700R4 bracket. The length is different. You could try adapting a TH350 detent bracket from some other donor car, something else that has a TH350.

You'll need some way to attach the torque arm. I think the kit has a provision for it. I don't know. I use a Spohn torque arm and it bolts to his new crossmember instead of the tranny. The Th350 rear mount is 2" forward of the 700R4 position also.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
LS6 Big Block buildup now in progress

Best results before the engine blew up
Best ET on a time slip: 11.857
Best corrected ET: 11.163
Best MPH on a time slip: 117.87
Best corrected MPH: 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!

Member of the Calgary Drag Racing Association

 

The torque arm IS attached already. and I think I have the driveshaft length problem solved. HOWEVER, do I need to hook something up to the vaccuum modulator????? you know, like a vaccuum line or something, or does it just stay open??? AND, is there any more tips on installing the detent cable? I have a performer rpm intake, and a edelbrock 600 carb if it helps any, thank you, again.

 

Find a vacuum source on the manifold for the modulator. You can pick up the hard line from any car in the junk yard that uded a TH350. That way there isn't a long rubber hose running the full length.

The detent cable attaches to your carb somehow. You may need a special fitting for the end to slip over. To set it, you pop up the plastic holder at the end. Move the throttle to WOT and push the holder back in. Release the throttle.