Valkyrii85TA

I have an '85 TA that I bought very cheap about a year ago. I know absolutely nothing about the history of this car. At some point in time, an 88 or later 350 was thrown in and everything is out of whack now. The car runs like crap, many little things were never hooked up, lots of stuff just rigged as a quick fix. It's a mess.

The engine that's currently in there is old and tired and we're getting another 350 to drop in her. My husband will be doing all the muscle work, but he's used to working on older cars and hasn't dealt with computers and whatnot very much. We're also working on a very tight budget, so I'm trying to avoid wasting any money on mistakes. I really want to be able to drive my car soon too! ;-)

Mostly what we're wondering is:

1. What issues should we expect to run into if we assume the previous owner just threw that 350 in there in place of the 305? The car is such a mess that I can't trust that anything was done correctly during the previous swap. What will we need to check and/or change to make the new 350 run smoothly?

2. The computer - How much pain is this going to cause? I have a nagging feeling there's a conflict there already, and that's why my car runs as if it's on death's doorstep.

3. And is there any advice, any at all even if it seems like common sense, that anyone would offer to make this go as smoothly and quickly as possible?

At the moment, we have no friends closeby that can help, so we're doing this all ourselves one weekend soon. It's a little intimidating!

Thanks!
-Christi

Air_Adam

Get a knock sensor for a 350. If its a TPI, and the 305 was a TPI, then it might have the 305 injectors. You need the 350 injectors. The knock sensor might be 99% of your problem if its a TPI car.

After those (or at least a check to see what you have) get a new cap, rotor and probably plug wires for it. They are probably worn out, 20 year old parts, if its like mine was.

Valkyrii85TA

Ack, sorry. I forgot to mention it's carbureted. The original 305 was as well. However, the current 350 was a fuel injected 87 or later TA engine. Whoever put it in rigged the carb to it. They put a tall deck intake manifold on the motor and it causes the carb to sit up too high, which in turn caused them to put some cheap aircleaner on it so it wouldn't hit the hood.

Like I said, it's a mess.

We're planning to stay with the carb when we get another engine. My husband tells me he would like to do away with the computer as well if possible, since we're not hooking up the emissions (my brother-in-law will inspect it for me).

Maverick_82

[QUOTE]Originally posted by Valkyrii85TA
[B]I have an '85 TA that I bought very cheap about a year ago. I know absolutely nothing about the history of this car. At some point in time, an 88 or later 350 was thrown in and everything is out of whack now. The car runs like crap, many little things were never hooked up, lots of stuff just rigged as a quick fix. It's a mess.

The engine that's currently in there is old and tired and we're getting another 350 to drop in her. My husband will be doing all the muscle work, but he's used to working on older cars and hasn't dealt with computers and whatnot very much. We're also working on a very tight budget, so I'm trying to avoid wasting any money on mistakes. I really want to be able to drive my car soon too! ;-)

Mostly what we're wondering is:

1. What issues should we expect to run into if we assume the previous owner just threw that 350 in there in place of the 305? The car is such a mess that I can't trust that anything was done correctly during the previous swap. What will we need to check and/or change to make the new 350 run smoothly?



That is exactly how I feel about the previous owner of my 82 TA.

five7kid

iTrader: (14)

There is nothing intrinsically wrong with the computer controlled carb on a 350. In fact, the factory put out a kit to install a ZZ4 crate motor and retained the CC carb. Most likely, your problem is being caused by the stock 305 exhaust, which kills a stock 305, let alone a 350. Don't waste your money on another engine unless you replace every piece of the exhaust. The Exhaust board has tons of information about that (Reader's Digest summary - '86-'90 TPI single-cat application headers, cat, and cat-back).

Most any dual-plane q-jet intake manifold should work. The GMPP manifold, same as used on the ZZ4 crate engine, is about 1/2" taller than the stock 305 intake. "Normal" air cleaners clear the hood with that manifold. The Weiand Action + is similar. In a pinch, the Edelbrock Performer will also do. The latter two are available in EGR versions (the GMPP is EGR-ready, too). The factory dual-snorkel air cleaner is a better choice than open element types.

With minor tuning, the CC carb works fine with a 350.

Air_Adam

Get a knock sensor for an '87 5.7 TPI car for it though. You WILL need this for the distributor and carb to work properly on a 350 (or any 4" bore block for that matter).

I made the mistake of running a CC carb/distributor on a 350 without changing the knock sensor (still had the 305 sensor in there) and the thing ran like a pig. It used up a whole tank of gas in about 150kms (roughly 100mi i think) and was totally gutless.

I put the 350 knock sensor in, I got one for an '87 IROC 5.7, and my gas mileage litterally doubled after that (little over 300kms a tank), as well as regaining ALOT of lost power.

The problem though, is that most people don't realize the knock sensor is different between a 305 and 350, and just stick the 305 peice into a 350 block like I did, and then wonder why it runs like a dog.

five7kid

iTrader: (14)

Should also have mentioned that there's no particular incompatibility between a TPI L98 longblock and CC carb.

But the knock sensor does seem to make a difference.

Breazlan

iTrader: (1)

Not too long ago I asked my local chev parts guy to look up the knock sensor for a 1989 305 TPI and then for a 1989 350 TPI. He said it was the same part number. How do you make the sensor swap then?

DURTYBIRD

Since it was a swap-in motor, make sure all the vacuum lines are connected. My carb'd 350 was swapped in too, and it runs like crap because a lot of the lines are cracked/disconnected. Even a tiny tube can cause a vacuum leak which in turn will make the car run horrible.

Air_Adam

It can't be, he messed something up. There are two different sensors.

five7kid

iTrader: (14)

Just checked partsamerica.com:

L98 sensor, GP Sorensen p/n KS7

LB9 sensor, GP Sorensen p/n KS2

If partsamerica knows there's a difference, GM should know there's a difference. However, you should know that GM parts counter familiarity falls off dramatically when the vehicle age exceeds 7 model years.

Breazlan

iTrader: (1)

Is there a way to convert the number stamped on the knock sensor to the gm number

Air_Adam

If its original, then it should be a GM part number, shouldn't it?

Breazlan

iTrader: (1)

I think Delco Remy number. DR562 xxxx
I have a couple of them that are this format.