Rebuild or Swap?

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Old Dec 2, 2017 | 03:43 AM
  #1  
harpelt's Avatar
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Rebuild or Swap?

Need some opinions. My '68 Cutlass Holiday Coupe has the original 350 and 2-speed Jetaway trans. The transmission has a slow leak that I have tried to find over the years to no avail. I am finally ready to put some $$ into the car. My question is do I get the original transmission rebuilt or do I sawp it out and upgrade?

The car is not all original. I have added dual exhaust, and a 4BBL carb over the years.

I love driving this car, and will likely be upgrading the suspension to improve handling, (plus make it safer for my 18 and 20 year old boys to drive). But I'm not looking to make it a racer.

My own skill level and limited garage space make it really difficult for me to actually attempt a transmission rebuild myself.
Old Dec 2, 2017 | 04:39 AM
  #2  
droptopron's Avatar
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If it was me I'd upgrade. A T350 is an easy swap & won't break the bank
Old Dec 2, 2017 | 08:05 AM
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That Jetaway is going to be hard to find rebuild parts for. As suggested, swapping it w/ a built TH350 is pretty straight forward and avoids the need to rebuild your JW yourself and will still be rebuild-able in the future. I swapped mine w/ a CK-built TH200-4R to get the OD gear and lockup TC, more to offset my rear gear swap from a 2.78 to a 3.90. While I'm still rocking the 2bbl presently, I've got more ambitious plans for my car (~400 HP on an engine rebuild). But until then, the deep 1st gear of the 200-4R / 3.90 gets me off the line with way more authority than it did originally. The final drive ratio is actually better than originally.
Old Dec 2, 2017 | 08:07 AM
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If it were mine I would upgrade.
Old Dec 2, 2017 | 09:17 AM
  #5  
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Rebuild parts for the Junkaway (including the switch pitch torque converter) are readily available from Fatsco.

Having said that, I'd go with a TH350.
Old Dec 2, 2017 | 09:57 AM
  #6  
tru-blue 442's Avatar
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TH 350, straight forward swap.
Old Dec 2, 2017 | 03:13 PM
  #7  
oldcutlass's Avatar
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X6 swap with a T350.
Old Dec 2, 2017 | 04:37 PM
  #8  
harpelt's Avatar
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Ok so it’s unanimous a TH360 is the way to go. What do I need to do with the steering column shift linkage and indicator?
Old Dec 3, 2017 | 07:24 AM
  #9  
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Originally Posted by harpelt
Ok so it’s unanimous a TH360 is the way to go. What do I need to do with the steering column shift linkage and indicator?
There isn't much you can do short of replacing the steering column and speedo with parts from a TH400 car. The linkage will work with the TH350 just fine. The shift gate in the column will not have the correct detents for a three speed trans, however. There is usually enough travel in the shifter to let you access all gears, however the lever won't lock in the detent in second and first.
Old Sep 9, 2018 | 07:45 AM
  #10  
harpelt's Avatar
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Any Experience with B&M TH350 replacement?

After all the advice I am looking for the TH350 to put in my cutlass. Anyone have any experience with the B&M TH350 aftermarket trannys? looking at the B&M Street/Strip TH350 from Auto Anything. Besides the transmission I know I will need the torque converter, dipstick. Do I need a new flexplate? Kickdown cable? The original Jetaway has the switch installed above the accelerator pedal. Will I need a new pedal to connect to the kickdown cable?

Any advice appreciated. Also, if anyone knows of an already rebuilt TH350 for sale that would fit my '68 cutlass near Lancaster, PA i'd be interested in talking to them.
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