Replacing 79 chevy engine with 90s engine


#1

is it difficult or do I need to deal with computers


#2

If you’re talking about fuel injection then yes, you’ll be dealing with computers with the related engine management and emission components.

Tester


#3

Is it that you have a good deal on the 90"s engine? Remember emissions regulations(if any)in any decision you make.Tell more about your plan.


#4

i just want to put something in it that will get better mpg i dont have a engine i am just trying to get some ideas. but i dont want it to be to difficult


#5

What do you have now? a half-ton pick-up with a throttle body 5.0 or 5.7 An engine swap to save money on gas may not be possible (you may spend more on the swap than you will save in gas)Any idea on your current mileage?.Transmission type and rear end gear ratio. I swapped a GMC 305 V-6 2barrel with a truck 4-speed for a rebuilt 350 4 barrel and a 3 speed auto and got maybe 5mpg better and it sure cost alot.The V-6 was so underpowered I did not enjoy driving the truck.


#6

A '79 is carbureted.

If the engine is worn, a transplant might make some sense, perhaps with an aftermarket fuel injection system. But unless the vehicle is otherwise valuable, the economics won’t make sense.


#7

Ask an independent shop or a speed shop about swapping years. I’m not sure about the incompatible years but you must watch the balance of the engine with the components that you swap over from the old ( flywheel and harmonic balancer ) and the fit of the old intake manifold.


#8

It’s doable, but it’s not a walk in the park unless you use an aftermarket FI system. The aftermarket FI systems are expensive though.

You would be far better off by doing the following.
Minor stuff could be advancing the timing a couple of degrees, making sure the vacuum advance mechanism is working properly, and making sure the carburetor is right, and by right I mean that it’s working and/or overhauled properly.
The latter could be especially true if the carburetor in question is a Quadrajet.

Some more advanced things that could help would be a camshaft change and changing the rear axle ratio. Going to a set of gears such as 2:56s will drop the RPMs way down, especially if the vehicle has an overdrive transmission.
I changed a vehicle here (TH350, no OD) from 3:42s to 2:56s and it knocked about 800 RPM off at 60 MPH. With an Overdrive transmission the dropoff would be much more than that.
(And surprisingly enough, the 2:56s did not kill the off-idle/low speed performance very much at all)


#9

It’s not an ignorant question at all.
And what’s better; a proper running carbureted vehicle or a computerized vehicle that has been tooling around for the last year or six with the CEL on?

As a poster on this forum stated some months back: “All of my friends have been driving around for months and years with the Check Engine Light on”.


#10

Probably a carbureted vehicle is the functional equivalent of a computer managed vehicle with the CEL on–if it has multiple sensor failures.


#11

I can’t imagine what kind of car from 1979 would be worth the hassle. Depending on the vehicle there are some quick and affordable ways to handle this. For example, if it’s a V8 American car, you can pull everything carb related and put on an aftermarket throttle body setup that will net you a few mpg’s and better performance.

If you need good mileage and haven’t got much money just go find an old Honda Civic or Toyota Corrolla.