phillips066

I want to swap out my 231 v-6 for a v-8 which would be the easiest to swap in? I'd like to to the sb chevy just for dollar for bang.
Would I have to swap the frame mounts to drop in a 350(chevy) and how hard is this to do? any info would be a great help.

J-(Chicago)

You will definitely need another transmission or a converter plate.
Buick/Olds/Pontiac transmissions won't bolt up to Sbc.


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v8vegawagon

He just did this same swap on the same car that you are talking about, and would be able to tell you of anything to look out for.
He used a 4 speed manual setup though.

Oldsguy

Or, put an Olds 350 in there and don't worry about it.

captjim

Actually a 350 Buick is the easiest swap. This guy has a good tech section on swapping, http://www.robertpowersmotorsports.com/

phillips066

I want to go with the easiest swap. Will a buick 350 or 455 bolt to the tranny? and would I have to move the frame mounts?

Oldsguy

I don't think Buick built a 455, it looks like that link referred to is for an Olds 455 into an '86 Cutlass, don't know how much would apply to the '78 Cutlass in this thread.

joe_padavano

Buick, Olds, and Pontiac ALL built unique 455s. Haven't you ever heard of a Buick GS455? And 78-88 G-body cars are pretty much identical mechanically.

Oldsguy

Probably heard about it someplace but really didn't remember it. Looks like that link will work for phillips066 then, great. Thanks for the clarification Joe.

captjim

One nice thing about the 350/455 Buicks is that they are the same externally. The fuel line is on the drivers side, and a few other things different from Oldsmobiles. In a lot of places, 350 Buicks are cheap, too. We have one in a 71 Skylark D/D. It runs great, lots of low rpm torque and throttle response, fun to drive. You don't need much gear with one, either. They are not high winders. IMO, they are underrated.

68/70 Cutlass

What ever engine you put in you will be changing frame mounts, exhaust, radiator / shroud.

fast68

all you need are the block mount brackets and the engine mounts for a non-chevy division car or truck

trucks include 78-85 with oldsmobile 5.7L diesel

whos to say that the 200C trans behind the v-6 231 isnt the univeral 10 bolt pattern to fit all divisions of gm

pull the engine and check that


may not have to swap to a trans with universal or non chevy pattern housing

exhaust work will need ot be done though to convert to chevy or whatever engine

can get headers for cheap and s curved extensions for 12 bucks each at summit racing and use straight length pipe and cheap mufflers

can make whole exhaust for it for less than 200


less than 125 or 150 if you find good used headers

unpainted LT's that is

in which is how i am going to exhaust m,y 82 trans am soon



good luck

88 coupe

To elaborate on an earlier statement:

And, each of those divisions, used different mounts.

Unless one is prepared to do some fabrication, it would be more practical to use the mounts that match the actual application.

Norm

arocars

A 1978 Cutlass is a G-body car. The earlier Cutlass's were A-bodies.

Its my understanding that Canadian Cutlass's used Chevy 305's. Using the frame and motor mounts and accessory brackets from one of these vehicles will put you ahead of the game. They are plentiful and not expensive. ...... Personally, I like keeping an Olds all Oldsmobile, but if you dont feel that way, the Chevy engines are cheaper to build and there is a bigger variety of parts available. ..... Dont forget that all G-body cars are basically the same and many parts interchange. 78-88 Monte's, Regal's, GN's, Cutlass, 442, H/O, Gran Prix's. Its been my observation that many Cutlass and Regal parts interchange and/or look practically identical. This includes interior pieces and some body parts. ..... I wouldn't trust a 200C to handle any decent power. They a light-duty transmissions. They definitely wont handle a big block or high output engine. If you can afford it, switch to a 2004r automatic overdrive. That way you can take advantage of shorter rear-end gears without sacrificing gas mileage. .... Lastly, also check out realoldspower.com and gbodies.com (I might have the second site name wrong, do a google search). Both of these sites have LOTS of info on 78-88 G-body cars. Putting a big block Olds or Chevy engine in a 78-88 Cutlass has been done a thousand times. Check out those sites and learn from those who have already been there, done that, it'll save you time, money and aggravation.

joe_padavano

Norm's spot on. It would be a COMPLETE waste of time to fabricate anything. This is a complete bolt-in. All 78-88 A/G body cars use the same frame, at least in front of the firewall. The crossmember under the engine is the same and is punched for engine mount pads for engines from each of the GM divisions. Mounts for the Olds 307 are common and can be used with any small or big block Olds motor. Chevy 305 mounts are also common and can be used with any Chevy motor. Mounts for a Pontiac 301 will let you install any Pontiac motor.

Of course, the mounts are only part of the problem. Each of the unique engine families requires the correct accessory brackets, pulleys, exhaust mainfolds, starter, etc. The accessory wiring and hoses may need to be moved from one side to the other to match. Of course, the trans needs to match the engine bellhousing - either Chevy or BOP, depending on the engine choice.

80 cutlass man

I just got through converting my 80 cutlass supreme to a chevrolet drive train. The swap was not that dificult to do but i am a professional mechanic. I am running the serp [one belt] belt setup off a 89 chevrolet pickup full length headers 2.5 true duals with an H pipe flowmasters turbo 350 with a B&M shift kit you can go down to the parts house and buy the pecises you need but you will have to do al lot of research my radiaror hoses are off a chevy truck my power sterring pully rubs my gear box but i have a fix for that. an 01 pontaic grand prix 3.8 supercharged pully is the same belt width same shaft size but the pully diameter is 3/4 inch smaller than the truck pump pully. I had to cut and reinforce my cross member on the driver side to run my duals exaust. trim the ear where the dust cover bolts up to clear my headers. lenghten my starter wires to run to the pass side. I am building a 383 stroker motor out of a 76 350 4 bolt main with a set of dart iron eagle heads that will turn 7000 rpm. if my car was a special or rare cutlass i would have left it all olds but its not. iI got the car when i was 12 years old its a 1980 2 door cutlass supreme 260 cu turbo 350 non lock up nothing special. I plan to also put a 9 inch rearend underneath.

80 cutlass man

I just got through converting my 80 cutlass supreme to a chevrolet drive train. The swap was not that dificult to do but i am a professional mechanic. I am running the serp [one belt] belt setup off a 89 chevrolet pickup full length headers 2.5 true duals with an H pipe flowmasters turbo 350 with a B&M shift kit you can go down to the parts house and buy the pecises you need but you will have to do al lot of research my radiaror hoses are off a chevy truck my power sterring pully rubs my gear box but i have a fix for that. an 01 pontaic grand prix 3.8 supercharged pully is the same belt width same shaft size but the pully diameter is 3/4 inch smaller than the truck pump pully. I had to cut and reinforce my cross member on the driver side to run my duals exaust. trim the ear where the dust cover bolts up to clear my headers. lenghten my starter wires to run to the pass side. I am building a 383 stroker motor out of a 76 350 4 bolt main with a set of dart iron eagle heads that will turn 7000 rpm. if my car was a special or rare cutlass i would have left it all olds but its not. iI got the car when i was 12 years old its a 1980 2 door cutlass supreme 260 cu turbo 350 non lock up nothing special. I plan to also put a 9 inch rearend underneath.

80 cutlass man

Technically a 78-80 model cutlass is still an A body in GM paper work but they have moore in common with the 81-87 G Body cutlass