Restoring old Powerglide vs upgrading to modern aut. transmission

[mossberg]

Hello to you all!
Well, I have this old -58 Impala which I try to preserve and improve bit by bit.(check my picture gallery to get an idea of what it is)
The driveline today is a 348 + powerglide + the std. 3,38 rear-end.
The 348 will stay forever but the rest can maybe be discussed. The intention is to keep it a classic cruiser with the original column shift system "looking like original".

So - within 2-3 years I probably have to decide between restoring the Powerglide or trying on installing a more modern tranny with all the benefits of lock-up or even overdrive features that could be very nice to get.

So - has anyone any good or bad experiences of doing this on an old -58 with 348?
Is there any "conversion kits" existing in the US market, with all the stuff necessary for doing a swap to maybe a TH700 or even a 4L60E?

Or do you think I´ll better stay with my old cast-iron PG and enjoy the good feeling of "the old days" instead of the better comfort and economy of a "low rpm" conversion.

I am very unsure about wich way to go - what is the general oppinion?

Greetings from Sweden

 

[Rockfish39]

Lucky for you...

Because Chevrolet V-8 engines all have the same bell housing bolt pattern, you have choices. Unless you plan on spending alot of time at the drag strip, a 1987 (or later) 700R4 AOD trans is hard to beat.

a more rugged, but more expensive, solution is a TH-400 with a Gear Vendors OD unit on it is also a very good choice.

 

[Ronnie Russell]

I would also suggest T-200 R4. Easier installation than the T400. Either would be a good choice.

 

[boxerdog]

Not knowing what freeway speeds are like in your area, a very simple, cheap, not-very-glamorous option would be a Turbo-350. No overdrive, parts everywhere, less weight, plenty stout, simple replacement and one extra gear.

I like my ODs too, but freeway traffic here is 80+ so it is a necessity. I'd vote for keep it simple unless there was a real need for the OD and/or lockup features.

 

[WENGINE]

In my dealings with those old cast iron PGs is not good. I have always refered to them as boat anchors. They are very heavy and as far as I can tell they rob the engine of power. Chevrolet on their 6 cyl. models had to up the cubic inches and HP with the PG to compensate for the loss of power. I am installing either a 400 or a 700r4 on the back of mine and I am told that the install is a bolt on . Unless you are bent on keeping the car absolotly original I would update.

 

[58 YEOMAN]

I also have a '58. I have a fully worked 200-4r that i had it my chevelle a few years back. it's an all out race trans, rev man valve body, 13 vane pump billet internals. Anywho, Being that i've only had this car for about 2 1/2 months, i haven't really been under it for any great length of time.
I see "kits" to bolt in a 700r4 into a 59-64, but not a '58.
What kind of cross member mods are necessary to put this in?
In my chevelle all i had to do was move the cross member back, even used the holes that were there from the factory!.
How hard is it to convert the column shifter to work with the od?

Sorry if i hi-jacked this thread, but hopefully this may be able to answer the original posters question, as well as the questions of others.

 

[dgwar]

I put a 350 in my 61 and it does really nice, It is a driver.

 

[Fiftiesman]

58 YEOMAN & mossberg,

The 200R4's work really nice behind a 348 that doesn't produce big HP/Torq (300 or so). But if the motor is built up and will produce say 400-450 HP with the torque say around 475-500 ftlbs, it would be better to put a 700R4 behind it (If an overdrive is what you're after). As far as the crossmember goes.. Bowtie Overdrives (Bowtieoverdrives.com) can furnish a "ready to install" cross member for your 58 (for either the OD's or the 350/400 trannies). I have one in my 58, with the 348/700R4 set up and it bolted right in (the cost =$75.00) it fit very nicely. It does move the trans back a couple of inches (from the stock PG location), so a drive line mod is in order. But not so far back as to interfere with the parking brake cable bracket assembly in front of the DL tunnel.

Hope this helps.

 

[oldskydog]

200R4 is a near perfect fit and can be built to take lots of HP with heavy duty parts. Less mods required. Driveshaft should be a bolt in since it's almost identical length as the PG and as I recall, the rear trans mount is only off by less than an inch.
Column shift rod has to be modified or fabricated on any replacement and is available from after market suppliers like Eklers Late Great.

 

[58 YEOMAN]

i just looked on the bowtie overdrives site, and they offer a cross member for a 200-4r but it's for 59-64 not a 58. I will call them on monday to ask why the difference and see if they can/are willing to make one.

 

[gbafus]

I had a '84 Buick Electra with a 200 4R. I had to have it rebuilt at 96k. The rebuild lasted about 38k & went bad again. I was told the 200 4R was barely strong enough for a full sized Buick. I sold the car for $300.

 

[AZ409]

I've used 200R4s on a couple of projects, much easier to work with than the 700s. If they were good enough for the 87 Buick nationals and GNXs they are OK with me.

 

[58 YEOMAN]

Mine is from an 87 grand national. but it's built will all art carr parts. built to handle 900hp, so i think the 180 from the 283 should be no problem for it.

 

[jim_ss409]

Here's my opinion,,, ANYTHING is better than a Powerglide.:evil I had a 200-4R behind a fairly mild 409 and it was great, but even a regular TH350 would be a HUGE improvement over that lousy Powerglide. I think the Powerglide is only good for guys that want to keep their cars completely original. A two speed transmission might be fine for a front end loader or some kind of farm equipment but it's no good for a car.

 

[Ronnie Russell]

Gee wiz, Jim, You are being a little rough on the glide. Barry runs a 2 speed, tried a Turbo 400 for a while then went back to the glide. Seems to work pretty good.

 

[jim_ss409]

Gee wiz, Jim, You are being a little rough on the glide. Barry runs a 2 speed, tried a Turbo 400 for a while then went back to the glide. Seems to work pretty good.

Okay, you got me on that,,, they do work well in a powerful drag car.:
But I still think they're the worlds worst transmission for the average street car.

 

[Ronnie Russell]

Agreed, Street car needs the 3 sp. trans.

 

[rstreet]

Gee wiz, Jim, You are being a little rough on the glide. Barry runs a 2 speed, tried a Turbo 400 for a while then went back to the glide. Seems to work pretty good.

way to go Ronnie...305/iron cased powerglides forever
robert