Okay, I'm definitely getting a 1978 350 truck engine to replace my totally dying 89/90 truck engine with the bad rod/bearing. The guy is giving it to me for free and I'm going to rebuild it before putting it in.

I really need help on a couple things because I don't want to screw it up.

Will this engine engine be compatible with the TBI computer? I was doing a search on cams and the stock cam listed at Advanced Auto for the 78 says it's not compatible with a computer.

The cam has me concerned. Will a new cam for a 1989/90 truck engine work or is there some kind of gear differences or something? What about the timing gears and chain? Is the block basically the same and can use later model parts?

I just want to make sure it will actually run after it's put in. I don't even know if the heads will have the threaded holes in the right place for the front mounts for the belt and accessories because I was thinking about keeping the 1978 heads instead of putting my 89 305 heads from the original vin E engine on it. Right now it has a 1989/90 350 truck engine with the 305 heads and a standard/stock 1989/90 truck cam and it works fine other than the rod that's ready to fly through the block.

Will my distributor work?

I wish I could afford a newer one with a one piece rear seal, but I can't afford to buy one and also rebuild it and don't have money for rods, pistons and a crankshaft to rebuild mine, and since it's a 1978, it's definitely getting new rings, bearings, lifters and seals.

Any compatibility tricks/fixes for the TBI computer will be GREATLY appreciated.

 

You can put any flat tappet cam into any SBC.

 

Thank you.

What about the flywheel flex-plate? Anything have to be done to make it work with the 700R4?

 

Should bolt up. Most flexplates are dual patterened to work with either the large or small diameter converter bolt patterns. Easy to check with the engine out of the car- just hold the flexplate up to the converter and make sure there's a set of holes that lines up with the bolt holes in the converter "legs."

 

That's definitely good news!

I know I will have to change the starter since mine is off the original 305. I was cracking starter housings on the 350 until I found out the flywheels are different.

I am going to reuse my cam since it has few miles on it and just replace the lifters as someone here suggested.

I will use my intake and just ream the bolt holes to fit the 78's heads. I was going to try and rebuild the 78, but decided that I'll do it at a later time, unless the guy who is giving it to me says it smokes or something.

 

Why don't you want to keep the 89/90 heads?

For as relatively cheap as a new flat tappet cam is, I wouldn't bother taking a chance on reusing it, even with new lifters.

 

I don't see any need to keep them since it already has regular 350 heads on it. I'm simply going to drill the intake to make it work with the 78 heads.

The 305 heads have worked well, but I'm still hearing some pinging.

If I had the money, I would simply have the existing engine bored, have a new crank put in an forget about it, but I'm broke.

Also, the guy who was going to give me the 78 is messing with me now. I don't think I'm going to get it, but hopefully something else will come along.

If I just had a block and could buy parts a little at a time, that would be nice!

I just want a car that runs. I'm not into racing or anything like that. If it gets me from a-b I'm happy and right now it's the only car I own and don't have the money for another one. I had to junk my other car because of the engine and I'm sure I said it before that getting rid of this car is not an option because of the sentimental value from my momma giving it to me the night before she died.

 

It has the worst of the worst 350 heads, though. Keep the ones you've already got, unless there's something wrong with them.

 

I just assumed that since they are the actual 350 heads for that engine, it would run better than using the newer 305 heads? I won't be out racing, but I would like to have a little power for when I'm not racing from stop lights to the speed limit. lol

Okay... I'll admit to the occasional stop light thing. Not right now with the (one) rod ready to fly out the side of the block though.

Are the valves a little larger on the 350? Will it make much difference?

I read somewhere that the 78 got a little HP increase, although someone said to forget that with the 89 stock style computer cam?

 

There was no "horsepower increase" in 78. Blee dat. Wherever you read that, don't ever trust it again, because they must have been on some of those good mushrooms people were growing back then.

It was 165 HP for a 350 2-barrel and 180 for a 350 4-barrel. Didn't matter what sheet metal it was wrapped in; they were all the same, the only difference being which manifold they bolted on top. 882 or 624 heads, the ground-pounding 929 cam, 8.2:1 or thereabouts compression ratio.

Your 305 heads will raise the compression probably to the mid-high 8s. Not enough to make it ping, on that short block. The smaller valves will hurt less than the higher CR will help in this case. Put one of the cheeep Summit cams in it; they're not "good" cams, but what you've got, is basically what they're meant for, and they work well for it. The 1102, otherwise known as the "RV cam", will work fine with your stock TBI setup, if you get 350 injectors, chip, and knock sensor for it, even though it doesn't say "computer compatible" in its ad copy.

 

I think the guy was just messing with me anyway because he won't return my emails, so I'll have to try and find something else. It's hell when you're broke. lol

This is where I got the info:

http://en.wikipedia.org/wiki/Chevrol...l-block_engine

The 1973–1974 L82 was a "performance" version of the 350 producing 250 hp (186 kW) and 285 lb·ft (386 N·m) from 9:1 compression. It was down to 205 hp (153 kW) and 255 lb·ft (346 N·m) for 1975. It was the optional engine again in 1976–1977, producing 5 hp (4 kW) more. The 1978 L82 recovered somewhat, producing 220 hp (164 kW) and 260 lb·ft (353 N·m), and then 5 hp (4 kW) and 10 lb·ft (14 N·m) more for 1979. 1980 saw yet another 10 hp (7 kW) and 15 lb·ft (20 N·m).

 

That's the L82.

Those didn't get put in trucks. You don't have to worry about that. If you have a truck motor, it was either a 165 HP 2-bbl or a 180 HP 4-bbl. That's all there was.

 

I wonder why they didn't put a more powerful engine in a truck? They need to haul heavier loads than a car.

So with my heads and the cam you mentioned, it would be somewhat of a weird setup? lol Wonder what the HP would be? About the same as what I have now? Whatever that is...

Funny thing about the rod... It's been like that for 8 years, which is when the engine was generically rebuilt and doesn't seem to be getting any worse. I've had the RPMs way in the red a few times and nothing changes. It's the number 2 cylinder and if you disconnect the spark plug wire, it seems to knock continuously, otherwise it only knocks when you let up on the gas. Oil pressure has stayed the same all these years. about 15-20 at normal speeds and 0 at idle, although before it's warmed up, it will go above 30 and then work it's way down as the oil is warmed.

I wish I could afford another crankshaft, but it's just not happening.

When it was in a truck, it was severely overheated and cracked both heads, which is why I used the 305 heads. I guess it must have damaged that part of the crank and wasn't improved with new bearings?

Sometimes I wish I had just rebuilt the 305 since all it did was smoke.

 

Truck engines need low RPM performance, which isn't conducive to high power output.

 

Okay... The guy with the 78 was definitely messing with me, so I have someone with a 93 truck engine who thinks it has a blown head gasket because it has some coolant in the oil.

Isn't 93 when they changed the engine? I need to find the specs on it because I don't even know if it would be compatible with my 89 computer and heads? It has been running kind of strange since changing the cap, rotor, plugs and wires until tonight when it got into the low 40's, high 30's.

It's been running kind of screwy in temps above 50 F.

 

1993 Truck is a 350 TBI engine with swirlport heads. An improvement over truck engines of old... but it's pretty much just a bigger version of what you find in stock RS'es... Maybe 200hp ish?

1996 Is when the Vortecs came out.

 

So that means if it's a small problem such as an intake gasket, I can put it in and my existing computer will work without changing the heads? Will my 305 exhaust manifolds bolt up to the swirl port heads? Eventually I want to upgrade the exhaust system, but right now I have no money and will have to scrape just to make this work.

I'll be be getting the 93 for $100, which is a guaranteed price from someone local, but like I said, he told me there is water in the oil from a head gasket or something. I've heard intake gaskets can do that, which would be awesome if that's all it is!

Anything to look for to find out if it is an intake gasket? I think the intake is still on the engine, but he didn't say.