[242177P]

Originally Posted by Chief of the 60's

Here is some food for thought as well as looking at this from an economical angle.

Twice a year, 40 miles, round trip.

Stop telling him what you would do. SBC, 700R4, 9 inch.

[Chief of the 60's]

Originally Posted by 242177P

Twice a year, 40 miles, round trip.

Stop telling him what you would do. SBC, 700R4, 9 inch.

We're not talking toques and back bacon here. Please chime in when you can speak "transmission".

[Carmine]

Originally Posted by Chief of the 60's

That right there is a text book example of an oxymoron.

Here is some food for thought as well as looking at this from an economical angle. That car with any non-OD tranny will tach at around 3800 RPM at 55 mph. With an OD, that same car, same engine and same rear gear will tach at about 2200-2400 RPM at 55 mph.

Now, without even talking about fuel economy, an engine that is running at a much lower RPM will last a hell of a lot longer because it is experiencing a lot less wear & tear.

There are also no tunnel mods necessary for a 700R4/4L60/4L60e.

Thanks for the info on the overdrive transmissions. What I said in my last post, I would never consider it an oxymoron. Occasional action at a red light and a trip down the 1340 once a year, if that ever happens, is far from abuse or beating this car. No slicks. No headers. No 4.33 gears. No motor changes. Just a little more get up and go with a transmission change would be fine with me. These cars when purchased new back in the day, I'm sure were subjected to abuse. Seen alot of them at the drags. Different story now, at least for me, Carmine.

[Sirrotica]

Originally Posted by 242177P

The folks that designed the Powerglide back in 1950 would simply not believe the point to which it has evolved. I love the TH400, but even I have to admit the TH350 is quite capable.

From a core standpoint, the 2 transmissions are going to be near the same price point. GMs engineering department already made the determination over 5 decades ago which transmission was superior in a muscle car.

Any muscle car near 400 CU IN came from the factory with the T400, not the 350, (until the smog era choked engines, where GM reconsidered using a 350 in Trans Ams). The reason was warranty claims, and the 400 would survive long enough to get a muscle car past warranty. In interest of longevity, the monetary investment is going to be close to equal, why wouldn't the OP go for at least what GM deemed adequate at the time the car was new? Shortening the driveshaft a couple inches, and moving the crossmember back a like amount, would surely be worth the added torque capacity to avoid breaking parts.

I fail to understand why when talking muscle cars, and the abuse they sustain, (because that's why people own them in the first place), the attitude is to use inferior engineered parts today, because it might be a little less work, or someone might save a couple hundred or so dollars over the stronger engineered parts.

It might seem like a great idea initially, but when you're laying on your back the second time under the car, removing a broken transmission that you thought would be adequate, the false economy of the original decision somehow fades quickly. I've been there and done it, and comments I post here on PY are a lifetime learned as a mechanic, and muscle car owner of nothing but Pontiac muscle cars, and racing them, and thrashing them for decades. First muscle car owned was a 67 326 HO Firebird bought in 1969 from the dealership I worked at, and I have owned and worked on literally dozens of my own, and other customers Pontiac rides to gain my knowledge and pass on recommendations.

Street use, oval track, autocross, road course, and yes more than a few straight line acceleration contests. Been there, built them, broke them and fixed them until the breakage was at a bare minimum. Conducting the torture testing so others could profit from my testing...……………

My testing program was done from my own wallet and making my living twisting wrenches on my own, and other peoples mostly Pontiac musclecars. The third picture in my signature shows the backdrop of Pontiacs in the late 70s and early 80s of my service station and garage where we specialized in Pontiacs. Now if someone has done more breaking of parts, and cost them more money, and time than my own testing program has, I'll gladly yield to their opinions, fair enough? I'll return to the earlier comment I made, "You can't build too strong, but you can definitely build too weak."

[Chief of the 60's]

Originally Posted by Carmine

Thanks for the info on the overdrive transmissions. What I said in my last post, I would never consider it an oxymoron. Occasional action at a red light and a trip down the 1340 once a year, if that ever happens, is far from abuse or beating this car. No slicks. No headers. No 4.33 gears. No motor changes. Just a little more get up and go with a transmission change would be fine with me. These cars when purchased new back in the day, I'm sure were subjected to abuse. Seen alot of them at the drags. Different story now, at least for me, Carmine.

If you only knew. Ha Ha! There was a parking lot between 2 buildings where Pontiacs were being built. That parking lot was known as the dragstrip.

[66sprint6]

We did the TH350 swap as it was just so darn easy., which is what we needed. We don't have a lot of resources to do much else. It certainly does everything we need it to. We were considering the 200-R4, but they are pretty hard to come by used. They haven't been made in a long time. We rarely venture far from home with the car, but if we ever do, it would be nice to have the overdrive. So it's on our wish list for now.

[Sirrotica]

FWIW, the 4L80E was made from 1991-2013, tons of cores out there in GMC, chevy light duty trucks and medium duty motorhomes etc. Up to 18,000 lbs chassis. A stock 4L80e is nearly as strong as a built 200 is, more work initially, but reliability is worth something.

[dbiggs]

Question about the TH350...I did the swap to TH350 but am having trouble finding the right tube...anyone have any idea what will fit a '66? Ordered one aftermarket and tried a couple others and none fit.

[66sprint6]

If you are talking about the dipstick tube, then I can tell you that aftermarket sucks. Every one that we tried didn't fit and they leaked like a bugger. We finally found a used GM dipstick tube on eBay and problem solved.

[b-man]

Originally Posted by dbiggs

Question about the TH350...I did the swap to TH350 but am having trouble finding the right tube...anyone have any idea what will fit a '66? Ordered one aftermarket and tried a couple others and none fit.

Look for a factory dipstick and tube from an A-body (‘72 and earlier) that originally came equipped with a TH350. I found one here on the forums by posting a ‘parts wanted’ ad, from a 1970 Tempest or Le Mans to fit my ‘64 Le Mans with a TH350 swap.

I used a similar strategy when I put a TH400 in another ‘64, using a ‘69 GP TH400 dipstick and tube which is the same a an A-body in this regard.

[connman]

I owned a 66 GTO since 1968. It rusted so bad that it was unsafe to drive about 20 years ago. During that time I had 12/13 motors in the car, from 326/389/455. And 350/400 SBC and 454 BBC. Transmissions ranged from 350/400 and the 4 speed muncie and a TKO600 5 speed OD. [ In my present 66 Lemans with a Ford 3:50 9". The 350 is an easy swap. It will bolt right in. Course a different flywheel is needed. The drive shaft will bolt right in. Watch out for a BOP case as chevrolet bolt pattern is different if you are buying one used. Also watch out for the ones with a lock up converter as they are not built to take the horsepower as the early ones. Also watch out because someone may try to sell you a 200 transmission as they look close to the same. The 200 has no modulator if I remember right. Rear trans mount bolts right in. The 2 speed rear mount is the same if I remember right. If you only go 40 miles out of town then the 350 is the way to go. If not I would put a 200R4 in it. I have never done that swap, but from what I read, [ I use to get every performance GM andHot Rod magazine. I still get 8/10 ] it is also a bolt in. Remember, they used it in the Grand National Turbo's. Example 3:55 rear gear 70 MPH 350/400 3200 RPM 4 speed 2900 RPM 5 speed OD TKO 600 2400 RPM and 1200 RPM at 40 MPH. I haveto hit 42 MPH before I put it in OD. Since you are stayig stock on the motor, You do not need a high horsepower transmission . I hope this info helps you.

[Carmine]

Good info. Thank you, Carmine.

[connman]

242177P: Yes, the 400 is a better trans, but 350 is a good trans. I have never broken one yet. I never put it behind a high horsepower motor tho. LOL, To put the 400 in 66, the crossmember must be moved back and different yoke and shorten the drive shaft. It was years ago like early 70's I put in a 455 and 400 trans. In order to mount the trans, we had to weld an extension on the crossmember and bolted it straight to the frame. Needless to say, even back then, finding a crossmember for a convertible was not eazy when I changed it back.

[Chief of the 60's]

Originally Posted by connman

I owned a 66 GTO since 1968. It rusted so bad that it was unsafe to drive about 20 years ago. During that time I had 12/13 motors in the car, from 326/389/455. And 350/400 SBC and 454 BBC. Transmissions ranged from 350/400 and the 4 speed muncie and a TKO600 5 speed OD. [ In my present 66 Lemans with a Ford 3:50 9". The 350 is an easy swap. It will bolt right in. Course a different flywheel is needed. The drive shaft will bolt right in. Watch out for a BOP case as chevrolet bolt pattern is different if you are buying one used. Also watch out for the ones with a lock up converter as they are not built to take the horsepower as the early ones. Also watch out because someone may try to sell you a 200 transmission as they look close to the same. The 200 has no modulator if I remember right. Rear trans mount bolts right in. The 2 speed rear mount is the same if I remember right. If you only go 40 miles out of town then the 350 is the way to go. If not I would put a 200R4 in it. I have never done that swap, but from what I read, [ I use to get every performance GM andHot Rod magazine. I still get 8/10 ] it is also a bolt in. Remember, they used it in the Grand National Turbo's. Example 3:55 rear gear 70 MPH 350/400 3200 RPM 4 speed 2900 RPM 5 speed OD TKO 600 2400 RPM and 1200 RPM at 40 MPH. I haveto hit 42 MPH before I put it in OD. Since you are stayig stock on the motor, You do not need a high horsepower transmission . I hope this info helps you.

Are you aware that the top dog GN was the GNX? And are you aware that the GNX only had 276 horse and that did not come in at the hit of the throttle? Even low horse GTO's had considerably more horse than that. And are you also aware that no 200 GM tranny was ever used in any heavy duty or other performance application? Are you also aware that GM killed off the 200 in short fashion due to warranty claims? Why? Because they simply do not hold up. Unless you sink $3000.00+ dollars on one, changing almost every internal part, they are junk.

Only fools and those that have already wasted their money on one believe in them. And using the "drops right in" excuse is lame at best.

[242177P]

Originally Posted by Chief of the 60's

Are you aware that the top dog GN was the GNX? And are you aware that the GNX only had 276 horse and that did not come in at the hit of the throttle? Even lowy horse GTO's had considerably more horse than that.

Bwahaha! My cheekbones hurt now.
Armchair quarterback.

[Chief of the 60's]

Originally Posted by 242177P

Bwahaha! My cheekbones hurt now.
Armchair quarterback.

Okay. How about you explain? Did the GNX have more that 276 horse? NO. Did Pontiac make a GTO with less than 276 horse? Not that I am aware of unless perhaps a '73 or '74, but this thread is about '66 and '67. I will wait for your enlightenment of the day.

[242177P]

Originally Posted by Chief of the 60's

Okay. How about you explain? Did the GNX have more that 276 horse? NO. Did Pontiac make a GTO with less than 276 horse? Not that I am aware of unless perhaps a '73 or '74, but this thread is about '66 and '67. I will wait for your enlightenment of the day.

Explain? Not a chance. You clearly have NO clue, and that's hilarious.
(BTW, 255 horse in 67 but that isn't even the funny part )

[Chief of the 60's]

So you have no clue. Thank you for your words of wisdom. I will cherish them.

[dbiggs]

If I can slip in a question to you knowledgeable fellas...swapped my 300 for a 350 but can't find a dipstick/tube to fit...any idea what will fit? Will a tube from any after 67 fit? Thanks

[b-man]

Originally Posted by dbiggs

If I can slip in a question to you knowledgeable fellas...swapped my 300 for a 350 but can't find a dipstick/tube to fit...any idea what will fit? Will a tube from any after 67 fit? Thanks

Since you’re not going to find anything earlier than a ‘68 TH350 dipstick tube from an A-body Pontiac I’d be looking to try one of those. For my own ‘64 Le Mans with TH350 swap I procured a dipstick and tube from a ‘70 Tempest to try, haven’t done the installation yet but pretty confident it will work.

After having done a couple of TH400 swaps into ‘64 A-body Pontiacs using ‘69 GP dipstick tubes successfully I am again pretty sure anything with a similar/identical firewall profile should be a good dipstick tube donor. The ‘69 -‘72 GP (G-body) and possibly a few years later were essentially an A-body on a lengthened frame, so you can safely assume the firewalls were nearly identical. Even found out not long ago that a ‘70 GP TH400 dipstick tube was a perfect fit in a ‘68 Firebird.

Good luck.