Hello all,

Well I posted this question on another site that is directly related to my inquiry, people are reading it, but none responding, so I figured I would try here and get a response.

Well this involves a GM product, BUT its a cool one. I was given a 58' Impala from my grandfather and am trying to restore for him to see before he passes away. Anyway it has the 348 W-block with the ol' powerglide. I am wanting to replace the powerglide with a TH350, which I was going to buy a rebuildable core for $75 and do it myself as I never have before and figured it can't be that hard. I have an opportunity to purchase a wrecked 90' Siverado for $500 with a 350 and 700R4. The trans has been rebuilt about 2,000 miles ago so it's good to go. My concern is I have had cars before with the TH350, but none with the 700r, and I've heard some nightmare stories of having the 700r, but have heard good as well. I want this car to be dead reliable and know it would be with the TH350, but in my eyes the 700r is questionable. I could by the truck take what I want and sell off the rest, but that would be a small hassle, or just get the TH350 and do what I origionally planned. What would you do? Thanks for your opinion.

 

Oooo Weee tough call, but if it was me I'd go ahead a buy the parts truck, and use the 700r and what ever else you need. also the OD will help on the millage. jmo

 

my opinion would be keep the powerglide.

 

I'd keep the original stuff-
On a stand in the garage sounds like the best place for them.
Drop in the TBI 350 and 700r4, but make it all reversible so in the future the original stuff can be dropped back in if a collector wants to give you an exorbitant amount for the car.
That will give you reliability, and some economy, plus parts will be easy to come by.
Above all, though, keep the original stuff and restore it as well. Fog and bag the engine, and store safe in the garage.

 

I'd go for the fuel injection and overdrive, more power and better mileage simple as that.

700R4s can be built to handle gobs of power. A guy I talk to at my local drag strip is putting 800 horsepower through a 700r4 in a firebird. I've talked to him for about 6 seasons now, the tranny was built once and its been in the car since.

 

not to be to insulting but come on people, the fuel injected 350 with 700r4 tranny combo is so BORING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!

everyone and their brother seems to put this exact same combo in everything.

the current set up is just as reliable as anything else that was produced, its not like is going to be drag racing it.

plus have that stuff in there to me is the car, the heart of it. what a thing to talk about when pulling up and someone asks to pop the hood. feeling that powerglide shift. those are things that make that car what it is.

more mpg...you kidding me? about to dump money in this thing for the "extras" and worried about mpg? rebuild whats in it and the money saved will be enough to buy fuel for years. and its not like the 350 is going to be getting 20mpg or anything.

alright, that was my opinion....again!

 

Does the 348 and 'glide combo work now? Just need a tune up or is it blowed up? Making that work is the fastest way for grandpa to see the car running.

Is he on some short fuse? Or do you have some time?

A '90 700r ought to be well out of the problematic early years.
http://www.hemmings.com/mus/stories/...feature14.html

SBC/700r in to that frame has been done a million times so it should be easy to make it work if you need to.

 

Count me on the 348/Powerglide side of this question. I doubt it's going to be a daily driver, so why not go original? You can build it as reliable as anything. Another plus, you won't have to have a junked truck laying around that you have to get rid of.

 

I know, but it's fairly solid and user friendly, plus it has all the aftermarket supprt you will ever need.
I'm looking to put together a 67 C10 short stepside for my dad, since he had one like that when I was a little kid. I'll use that same combo in that, for ease of use and install. Probably buy a wrecked pile and yank the drivetrain, rebuild it, and drop it in. Maybe even throw a new seat in it, tilt column, cruise and a/c if the donor has it, etc.

 

i met a guy at a gas station that had a 1970? model type chevy 4x4. he did some cool things to it, he got a donor 1988 i guess chevy truck and swapped in about everything. the engine and trans, plus he put the interior in also, it even had a third brake light on it and plastic side molding. but he kept the sas front.

 

Keep the 348 and PG, you don't see to many motors with the scalloped valve covers. It would be easier to restore. Try the Vintage Chevrolet Club of America (www.vcca.org) for some other info.

 

I absolutely agree. The car is much more valuable stock than if it is modified or changed in any way. The powerglide is a very dependable transmission and I would keep it. If the 348 is still good, I would keep it. It is rare as most were worn out or blew my years ago.

If you plan on rebuilding a 350 transmission because "it can't be that hard", you're in for a rude awakening. If you've never done it before, you have a better chance of winning the lottery that having the transmission work properly when you're done. Most dealerships hoped to have one mechanic that could work on them and make them work and some sent all of them out to a transmission specialist.

 

Well I appreciate the responses. The 348 will be retained and I have already rebuilt it. The Powerglide as far as I know worked in the car when it was parked in 1978, the only thing is it leaked bad from what my grandfather told me. The reason I am interested in replacig the P/G is I've driven cars with a 2 speed an I really don't like it, I like the drivability of at least a 3-speed. I'm not concerned w/ mileage as the car will not be driven on long trips, maybe 250 one way at the most. I'm not going to be getting rid of the P/G and the only thing that will not be stock that will be done to the car will be ride height and paint, everything else will stay the stock. As far as the tranny being rebuilt by me I teach a fabrication and performance class, so I am fairly confident I can do it with little issue ( and it doesn't hurt that one of my friends is a tech at a Chevy dealer and has rebuilt more than 1 TH350 ) I know how much these cars are worth and I will never sell it as my grandfather has had it longer than I've been alive, so I'm not concered with how much less the car will be worth if I put a 3-speed in it.

 

in that case through in the th350 and call it good.

 

What would really be nice is if you could find some sort of aftermarket, manually controlled "lock-up" torque converter. That would make the PowerGlide almost like a three speed.