V6 to V8 Conversion help
#1
V6 to V8 Conversion help
So i own a 1985 cutlass supreme with 3.8 v6 231 and a 200r4 transmission, the engine has a bad rod knock so i bought a 350 rocket out of a 1973 cutlass, with this bolt up to my 200r4 if not i have a 350 chevy v8 small block was gonna put it in my 64 but if itll bolt up to the 200r4 then might through it in the cutty any help or advice would be appreciated!
#2
It will, but the longevity of the trans might not be all that long. You're more than doubling the torque of that V6 with the 350, and if it has a lot of miles on it, you may want to go through it when you have the engine out of the car.
#3
#4
I would tell you to stay with the one in the car. They can handle that 350 just fine so long as they know what it's going behind. That trans with some different internal parts came in the Grand Nationals and the GNX and handled that power without issue.
#5
Yes the Olds motor bolts to the trans. It will not bolt to the frame pads, however. You need to change the frame pads to the correct ones for an Olds motor and use Anchor P/N 2328 motor mounts to match.
#6
This is one of the few times I'd suggest going with the SBC, simply because it's an easier swap than the Olds engine. Everything on the Olds engine is on opposite side of the car than the V6 or the SBC.
#7
Sorry, Glenn, but I have to disagree. The amount of changes required will be nearly the same in both cases. In fact, both the Buford and the Olds have the A/C compressor in the same place. The Chebby puts it on the other side of the engine compartment.
#8
These correct
Not gonna lie im new to these types of conversions but its extremely facinating and im excited to get into it, so converting to the rocket 350 can i use the old altinator and water pump from the V6 since theyre both olds motors? And would i have to get a different radiator then the one thats already in there?
#9
Not gonna lie im new to these types of conversions but its extremely facinating and im excited to get into it, so converting to the rocket 350 can i use the old altinator and water pump from the V6 since theyre both olds motors? And would i have to get a different radiator then the one thats already in there?
#10
The V6 is a Buick motor. The alternator, PS pump, and A/C compressor work, but you'll need the correct Oldsmobile mounting brackets and pulleys. The starter motor, flexplate, water pump, exhaust manifolds, and carb are all unique to the Olds motor. The radiator will need to be replaced primarily because you need more cooling capacity for the larger motor. Frankly, the simplest swap is a Buick V8.
#11
#12
#13
I suspected the Buick motor would be more difficult to find. Just be sure you collect all the little parts you will need.
#15
#16
The 350 Olds swap is pretty easy. Find a 307 Olds in a just about any 80 car, grab the accessories and mounting brackets, transfer them to the 350, and the engine will pretty much fall into place (assuming the frame mounts are swapped!).
As for the transmission, if it’s in good shape, get the TransGo shift kit with the big servo. I’d remove the trans while the engine is out, it will make the shift kit install much easier.
The 2004R trans in your v-6 cutlass is basically identical to one from a big Cadillac, ot the Grand National. The only difference between them is the valve body, servo, and governor. The internal parts are all the same.
As for the transmission, if it’s in good shape, get the TransGo shift kit with the big servo. I’d remove the trans while the engine is out, it will make the shift kit install much easier.
The 2004R trans in your v-6 cutlass is basically identical to one from a big Cadillac, ot the Grand National. The only difference between them is the valve body, servo, and governor. The internal parts are all the same.
#17
The 350 Olds swap is pretty easy. Find a 307 Olds in a just about any 80 car, grab the accessories and mounting brackets, transfer them to the 350, and the engine will pretty much fall into place (assuming the frame mounts are swapped!).
As for the transmission, if it’s in good shape, get the TransGo shift kit with the big servo. I’d remove the trans while the engine is out, it will make the shift kit install much easier.
The 2004R trans in your v-6 cutlass is basically identical to one from a big Cadillac, ot the Grand National. The only difference between them is the valve body, servo, and governor. The internal parts are all the same.
As for the transmission, if it’s in good shape, get the TransGo shift kit with the big servo. I’d remove the trans while the engine is out, it will make the shift kit install much easier.
The 2004R trans in your v-6 cutlass is basically identical to one from a big Cadillac, ot the Grand National. The only difference between them is the valve body, servo, and governor. The internal parts are all the same.
#18
Ok long story short after thinking about it carefully im going to use the sbc 350 for my 85 cutty, i have all the parts for it except the motor mount because im not sure which ones to use, and any advice? Thanks in advance!
#19
my advice? Stick with the Olds. No brand “X” chebby engines in a Olds!!!
And I don’t want to hear any crap about factory sbc installed in Oldsmobile’s. It was wrong then, it’s wrong now!
#20
i have this one candy painted and all chromed out already haha, but i appreciated the advice tho!
#22
#23
#25
#26
My dad and I made this swap many moons ago. It was not hard and we used the stock transmission. It was a casual driver and not a hot rod so the transmission done just fine behind the 1970 350 4 bbl Olds engine. We had to find the correct fan shroud and also had to find a transmission cable that would hook to the carburetor we had. I can't really remember now what cable we had to use for that? Been to long ago.
#27
1985 Oldsmobile Cutlass Supreme (Rear wheel drive)
Good Afternoon
I wanted to verify if I currently have the Automatic 200 metric trans with the Buick 3.8 liter in my
1985 Olsmobile Cutlass Supreme a small bock chevy with the Right frame mounts and engine mounts.
Chevy 350 turbo transmission should bolt up with no issues.
I appreciate your input
John
1985 Oldsmobile Cutlass Supreme (Rear wheel drive)
#28
Mr. Joe
Good Afternoon
I wanted to verify if I currently have the Automatic 200 metric trans with the Buick 3.8 liter in my
1985 Olsmobile Cutlass Supreme a small bock chevy with the Right frame mounts and engine mounts.
Chevy 350 turbo transmission should bolt up with no issues.
I appreciate your input
John
1985 Oldsmobile Cutlass Supreme (Rear wheel drive)
Good Afternoon
I wanted to verify if I currently have the Automatic 200 metric trans with the Buick 3.8 liter in my
1985 Olsmobile Cutlass Supreme a small bock chevy with the Right frame mounts and engine mounts.
Chevy 350 turbo transmission should bolt up with no issues.
I appreciate your input
John
1985 Oldsmobile Cutlass Supreme (Rear wheel drive)
#31
The 1978-1988 A/G body cars use completely different crossmembers for the 200-4R/TH400 as compared to the TH200/TH350. Unlike the earlier cars, the crossmember is not straight across and the frame is not symmetric. You can't simply slide it back, at least not if you want the frame to be structurally adequate. The 78-83 cars don't even have the correct reinforcement on the frame to accept the 200-4R crossmember. There is an aftermarket part available to correct this.
#32
The 2004r is a OD trans and the 200 is just a 3 speed so you should know from when you were driving it which trans you have. Also the shift indicator quadrant should tell you.
Last edited by Cutlass Fan; December 28th, 2021 at 02:58 PM.
#33
1985 Oldsmobile Cutlass Supreme (Rear wheel drive)
of the 350 SBC and the 350 short tail transmission also will the drive shaft need to be modified in length to fit.
Thank you for your input
John Moore
docholiday000@aol.com
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