Engine Swap for 1983 Cutlass Supreme

[MrSony]

Rear gear choice may be a big factor in the difference.

Potentially. 2.41 may get worse mileage than say a 3.08. Around town at least. Itd be marginal at best. Few mpg.

 

[CenturyAero]

The 3.8 wont get 18mpg without fuel injection.
Buick 350s are in basically every Buick from 1968-1980. And some jeeps from 68-71. The 68 and 69 oil through the rocker shafts (like a mopar 360, among others), and use solid pushrods so they need converted to 70+ pushrod oiling. 75-80 had HEI and stronger rods. Look around on Craigslist, facebook marketplace, etc for people parting out 70s Buicks. Demo guys use em a lot. Afaik a 455 Buick would require moving and welding the frame side mounts. Not hard if you can weld.
The 350 Buick uses all the same hookups, warer pump, timing cover (depending on year, older 3.8 covers have the pan bolt holes in right location), front end gaskets, starter, oil pump (same cover setup), etc. A 3.8 is literally a 350 minus cylinders 3 and 4, with a shorter stroke and deck height.

In 1980 Motor Trend tested a 1980 Century Limited sedan with a 231 engine and recorded 19.8 mpg on their 73 mile test loop. Federal EPA rating was 20 mpg. Car was new and engine was not broken in.

 

[MrSony]

In 1980 Motor Trend tested a 1980 Century Limited sedan with a 231 engine and recorded 19.8 mpg on their 73 mile test loop. Federal EPA rating was 20 mpg. Car was new and engine was not broken in.

Neat. Guess the 3.8s I've owned/rode in needed a tuneup.

 

[DoctorSwain]

Hi everyone. Thanks for all your help, some good conversation is going on here. Yesterday I worked on the cutlass for a couple hours. I removed the brackets that held the alternator and the power steering pump. I took off the belt drive that was behind the fan. I removed the water pump and unbolted and took out the fuel pump. Unfortunately I broke the fuel line connecting the fuel pump to the carb when I tried to remove the line from the carb. It looks like it will be easy to replace.

Today I am going to try and take off the distributor and the carb. Then I will remove the starter. Maybe while I am waiting on a new engine I can start to rebuild the carb. It is a Rochester dualjet 210. I have found some good videos on carb rebuilds and it seems like I could figure it out without too much of an issue. If I mess it up, I will just buy a new carb as they don't appear to cost too much.

My jack seems to be working now and I have the front of the vehicle supported with jack stands. I was able to get under the car fully and check out the exhaust. It seems to be in good shape except for a rusty old catalytic converter which is probably clogged and defunct. The bushings on the control arms and other areas of the suspension need to be replaced also.

Every time I look at the nest of wires I am baffled. How many of these are essential to the vehicle's operation? I have the alternator wire labeled and the engine ground and some other wires labeled; however, there are so many wires that just abruptly end with some sort of plastic connector on it.

Then there's the vacuum lines and the emissions systems. How much of this stuff is essential to the vehicle's operation? I know the computer was not operational when I bought the car, so I will have to figure out how to either reboot it or bypass it. Does anybody know anything about handling the ECM setup? There are a few threads out there and people seem to be split on retaining function of the ECM while using the emissions or going with an earlier model carb and HEI distributor where a computer is not needed. The fact that the computer was not operational leads me to believe I bought the car in "limp home" mode and would explain why I was only getting 11mpg when it ran. Luckily I am in Montana and there are no emissions tests.

I still haven't found an engine but all I can do for now is get the prep work done so I am ready when I find one.

-Greg

 

[timo22]

I have not forgot about you Greg. I should be buying a load of lumber next week. Usually a week or two out. I will contact the driver and find out if he is heading back west.

timo22

 

[DoctorSwain]

I have not forgot about you Greg. I should be buying a load of lumber next week. Usually a week or two out. I will contact the driver and find out if he is heading back west.

timo22

Awesome! Thanks Timo! The engine is almost ready to take out and the weather is getting warmer.

Here are some drawings I made: standard internal combustion engine, dualjet carb, engine mounting, bracket to frame mounting, transmission mounting, hot air shrouds, stove assembly.