Hi, i have a 91 rs with a blown 3.1 (what else is new here) and a 92 rs with an only slightly modified305 TBI. My problem is that over the winter i put my 92 into a guardrail and the entire front end is destroyed. I had some good luck though, the engine and transmission were not touched. I bought the 91 rs to do an engine swap but i need to know a few things first. one, will anything under the hood need to be modified besides the engine mounts. two, will the fuel system work the same for the two cars (ex fuel pump, etc.) and lastly, will the 3.23 rear end in the v6 car hold up to the torque of the 5.0 (yes no comments please, the 5.0 is temporary but i need my car back). I think the rear end is the same but with just a different gearing but im not sure. thanks for any input i will be starting this project soon and any info will help.

 

The rear end is the same so it will be fine. You will need a new fuel pump however.

 

ok because i read in another forum that the rear end in the v6 rs could only handle up to around 250 ft-lbs of torque and the 3.1 only put out around 180 (at the crank) but the 5.0 stock produces 255 and with the mod's done and planned on mine will be around 280-290. (headers, exhaust, cam, chip, andan open filter)

 

the rearend is the same rearend, . take the engine,trans , mounts ,accerator cable, exhaust , wiring harness,computer, fuel pump , rad. and fans from the V8 car and put them in the V6 car. you may also want to take the front springs from the V8 car aswell. the V8 will make he front of the car squat quite a bit with the V6 springs.you will need the tach from the V8 car aswell because it will read high with extra 2 cylinders ,i'm not 100% sure but i think the V6 front sway bar may be smaller also, another thing to check.or you could leave the V6 springs and just drop the rear to match, the lower spring rate on the V6 springs will help with weight transfer and get the car to launch harder.

 

From what I have found is the springs are the same in the 3.1 and the optional 5.0 in the RS. They are the weak *** ones good for the V6. You will pretty much just be swapping it all. You need to drop the rear so you can get the tank out and use the proper fuel pump so you might as goo all the way and swap rears. This will keep your speedo calibrated. Take your fuel lines and as stated you instument cluster. You may need to check into what needs to be done with registation. If there is no inspections then you will be registering a V6 and insurance would be lower If you want to keep it as the V8 car then there are ways around that.

 

wouldnt the tach be fine because the car is computer controlled and i have to swap out the ECU's and i think the ECU controlls the tach does it not? i thought they were all electronic after like 85 or 86? and yes the springs are the same in the two cars, they are both the RS model.

 

The tach still works directly off the coil

 

the rear gears in the V6 car rearend will probably have better gears than the 5.0 rear.alot of those were 2.73 or 3.08 and alot of the V6 cars had 3.23's. a 3.23 is decent street gear with a 700R.

 

yes, the 5.0 gears were 2.73's and the 3.1 rear was a 3.23