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Does it makes sense to swap the 2 speed ST300 with a TH350 or 200 ( or something w o/d) on an original numbers matching 64 GTO with 4bbl, auto, 3.23 posi?
Looking to make the car more drive-able. Want to take it to small meets and cruise around without stressing the engine or spending $$$ in gas.

If we keep the original transmission (moth-balled) will the swap decrease or increase the value?
What are some suggested "best practices"?
 

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My opinion, if you plan on keeping it for a while, upgrade the transmission to a later model OD automatic. Keep the original trans should you decide to sell. The big thing in value is the engine as often the original is long gone and it is the key to a better resale value. Others may argue this point.

As long as all mods are bolt in and can be returned to factory, I don't see a problem. If you start cutting or modifying, then you might hurt the value IF a potential buyer was looking for stock. Now if you find a buyer looking for upgrades or even plans on upgrading, you may still get a good resale value. It is hard to determine, or even speculate, what will bring the best resale value if you were to sell it. I would say its your car, just have fun with it and modify it anyway you prefer while you own it -just keep it Pontiac powered:thumbsup:. Keep the original numbers matching parts and don't hack anything up.

Make mine a Pontiac Gasser and the heck with original -probably get a higher resale too!:laugh:
 

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The TH350, although not an overdrive unit, is cheap, strong, and will bolt right in with no mods. Additionally, the first gear in the TH350 is a real first gear. The first gear in a ST 300 is 1.76:1.....which KILLS performance. Just swapping a TH350 into your car improve the car immensely: it will feel like you gained 100 HP, and your fuel mileage will increase. Save the numbers ST300 and no value loss will occur. Like Jim says, a built OD trans would be even nicer, but with 3.23 gears, not necessary. If I were in your shoes, I'd pop a TH350 in it in a minute.
 

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The TH350, although not an overdrive unit, is cheap, strong, and will bolt right in with no mods. Additionally, the first gear in the TH350 is a real first gear. The first gear in a ST 300 is 1.76:1.....which KILLS performance. Just swapping a TH350 into your car improve the car immensely: it will feel like you gained 100 HP, and your fuel mileage will increase. Save the numbers ST300 and no value loss will occur. Like Jim says, a built OD trans would be even nicer, but with 3.23 gears, not necessary. If I were in your shoes, I'd pop a TH350 in it in a minute.
I totally agree. The beauty of it is that it will directly bolt up (you'll need a BOP unit). You won't have to do anything to the driveshaft or crossmember. The only downside is that you won't be able to manually select first with the stock shifter. But with a properly tuned trans, you make the selection with your right foot. :wink2:

Then store your ST300 until such time as you sell the car. BTW, I've done something similar with my numbers-matching 69 Judge. The original 3 speed Dearborn sits in my basement while a Muncie 4spd. resides in the car. If I ever sell, the new owner will get both trannies in case he wants to restore it to factory original.
 

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Oh and one more thing - at a car show no one will be able to tell the difference unless they physically get under the car (points judging), whereas with a 200R4 the TV cable is a giveaway.
 

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Good advice. Thanks. If the car is not posi, how hard is it to upgrade?
Like all things, you can get your parts new, but you probably don't want to tackle this yourself if you don't have the experience in setting up gears. If you have the cash flow, you might consider a new complete rear axle assembly and just bolt it in and moth-ball your original.

Why posi? Some of us feel posi is not always the way to go for many reasons, mostly handling control in less than ideal sunny weather on a straight stretch. Posi in rain, snow, ice, wet leaves, loose sand, curves, can result in your car kicking out on you and becoming a handful to control. Most GTO's did not come with posi. I think geeteeohguy would recommend an airbag that goes inside your right spring at the rear to help plant the tires better without going to a posi.

If you know how to handle a car when it kicks out on you and you aren't prone to needing to change your shorts if it does, then it'll work for you -unless it doesn't and you wrap it around a tree.:nonod:
 

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Good to know. I had no idea. We will keep it as is. Thanks


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Yep, a nice single leg burnout can be more impressive to the onlookers ( and still catch the attention of your local police:cheers) and more controllable.:yesnod:

If you go with a TH-350, I suggest a shift kit be installed to firm up the shifting. They usually can be set to different levels of harshness. You don't want the "race" shift as it is slam-bang. The "street-strip" level is what I like. I used a Trans-Go kit in my brother's Mopar. I did not rebuild the trans as that is over my head, but I got all the heavy duty clutches/parts I wanted to use and supplied this along with a used trans for the rebuild. The Trans-Go shift kit allows the trans to shift automatically in "D" or manually by dropping down into "L", shift to "S", then to "D". Summit has them, ebay has them, and all reasonably priced. Pontiac actually did this with the GTO TH-400 with the His&Hers shifter. Put it in "D", or slide the stick over and row through the gear selection manually.

You will also want a new torque converter. I used a converter made by Edge Racing Converter on my brother's Mopar, 360CI street engine with Six-Pack. The converter is rated at 2,400-2,600 true stall, which means this is the stall speed it will rev up to when you slap the throttle to the floor putting your engine in a good power band. However, these converters are built "tight" so they don't slip much under normal driving, like around town, easy throttle, and act like your stock converter. This gives the car excellent manners around town and it does not slip like many racing converters do which cause additional heat in the trans and uses more gas. I watched his tachometer on the car and the RPM change between my foot off the gas pedal and then easing into the gas to accelerate to get the car moving again was a 200 RPM difference -so not a lot of slip before the converter began to respond. They have a converter for the TH-350 for street application for $254.50. I can recommend this because of my experience in purchasing one for my brothers car. He is not the "motorhead," I am, but he loves the driveability of his car and when he snaps the carbs open, it"ll light the tires up with no problem as he shifts it manually thanks to the Trans-go shift kit.

Just a suggestion to look into when you shop around for your replacement trans - whatever you decide to go with.
 

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Discussion Starter #11
Awesome info.Thanks so much. The car is all original but needs a rebuild on the motor,tranny,steering,brakes etc.
 

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4 speed, if you do all the labor: 2500--3500. 5 speed, if you do all the labor: 4000-5000. And that does not include a console for a stick shift. That will cost you another $1500 or so for a nice '64 console. Stick shift conversions make the car a lot more fun, and don't detract from the value. But, if I were in your shoes, I'd bolt a TH350 in and enjoy. You're looking at $500-$1000 total cost.
 
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