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First Engine replacement

I’m replacing the motor and it’s going to be my first time attempting it. I was wondering if anyone could give me tips on how to do it and maybe things to watch out for or check. Are there common mistakes people make or things that people usually forget while doing it? It’s a direct replacement with, hopefully, nothing different from the last motor. The trans is pulled out and it’s a manual if that changes anything. It’s a 1968 Pontiac Firebird that has a 1986-88 Chevy 350 (unsure on the exact year) but it had the dipstick on the passenger side. Its mated to a 1960 something m20, I forgot the exact year. I have an engine hoist and in reality only one friend who could help me with anything. Any advice would be appreciated.

I’ve only had a shop do it but the folks here are going to want to know what kind of car, engine, mileage, transmission, etc. plus what kind of tools and facilities you have available and if you have someone to help. Like garage, engine hoist, manual, etc.

Since it all ready has a Chevy small block, I would look at crate engines. Chevy even has “turn key” engine/transmission combinations available.
However, how was the first engine swap done? Was the wiring butchered?
This will be an extensive project. As Bing said, what kind of facilities do you have?

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I’ve done this numerous times. Sooo…

Make notes of where everything is wired. A 68 Anything isn’t too complicated wiring-wise but you will forget things. Get some sort of repair manual for the car - Haynes, Clymer, something - so you have a reference. As long as you are replacing a Chevy engine in your Pontiac now, your 86-88 Chevy engine it should bolt right in. If there is still a Pontiac engine in there, the bellhousing will not fit because it has a different bolt pattern.

The engine mount frame brackets might not fit. I am not sure if the Pontiac mounts are different than a Chevy. The mounts to the block are different so use 68 Chevy parts. The oil pan may need changing, not sure what you have in the car or on the engine. Doesn’t matter what side the dipstick is on unless it hits things.

Depending on what you do with the ignition, you need to do a little re-wiring. The 86-88 Chevy comes with an HEI while the Pontiac had a separate coil. Or you could install an electronic trigger aftermarket distributor like an MSD with a separate coil.

Pull the engine and trans as a unit. Make sure you have at least one helper. Keep your hands out of the area between the engine and the frame as much as possible. I suggest the car be on jack stands because you will need to get under it. Make sure you have space in front of the car to pull the engine away from the car because it will not roll on jack stands. Seems simple but I’ve seen people do this and it becomes an embarrassing hassle if you don’t. Re-install as a unit.

Don’t allow he engine to start right away. Disconnect the coil wire and crank it until the oil pressure comes up, then install the wire and fire it. Assume fuel lines will leak and watch for it with fire extinguisher. If they don’t, good! If they do, at least you won’t burn the garage down.


Get everything you can out of the way including the radiator, A/C system if present, power steering hoses, etc. A engine swinging just a little bit has a lot of momentum and can damage things very easily.


He os replacing a Chevy engine with a like Chevy, he has an engine hoist and I assume hand tools.What difference does it make if he does it u\in his driveway or garage?

Because it is his first time I agree about removing the radiator,
Take pictures of everything befoer you take it apart. Don’t hurry and good luck.

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A BIG +1 to that recommendation!

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I read the OP that the Firebird currently has an SBC and he is replacing it with another SBC.

I’m getting another Chevy 350 from that year. I guess I really wouldn’t know how to tell you the first one was done but it ran. The one thing that was wrong that gave me problems was the connection for the alternator wasn’t right. The connector was made for two pins and the alternator was 4 so the connector was cracked, I assume to make it work. I have a garage and a decently flat driveway I can work in.

I’d watch a bunch of youtube videos, in addition to everything mentioned above.

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I always can’t find much because I try to find things specific to my car. Will just videos of engines swaps help me a lot? I’ve watched a lot of engine swaps by big youtubers but they don’t show a whole lot of detail.

There were probably five wires in total connecting to the engine and 3 of them were on the starter so I don’t thinks it’s too bad. It’s already swapped to a 86-88 Chevy so it should be good. Do you by any chance have some tips for getting the shifter back in? It’s a Hurst shifter that’s pretty long and curves. Should I just put it back on when it’s half way in the car? I’ll try to make sure to not start it right away. Hopefully I don’t get to caught up in the moment and just go for it.

Wasn’t clear when I read the post for this thread but I saw one of the OP’s earlier posts about an L98 in the 'Bird.

All should bolt right up except maybe a mechanical fuel pump. Later engines don’t have the pump eccentric to drive it.

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Unbolt the shift lever, but install the shifter itself with the shifter rods. It should stick up far enough to bolt the lever back on. It should be just 2 bolts.

You can install the trans after the engine goes in. I used to drop the trans out when pulling the engine in my Camaro race car because of a tight garage space. Out is easy, putting it back in can be a bit of a grunt sometimes if the input shaft just refuses to slide home.

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Don’t worry it already has an electric one. Also I was unsure about the l98 because I only based it off the years and what the guy told me. I don’t think it is but I’m also not sure. It could be but it has a carb.

Alright sound good, thanks a lot