3100 and 3.1 Swap?

[91LuminaEuro]

So, my dad an I came up with a hair brained Idea the other night and I wanted some insight...

So we have our new 91 Lumina Sedan with a 3.1 that the bottom end is locked up tight. We also have a 3100 out of a 94 Regal that is in great shape. I know they don't directly swap, but how hard would the swap be?

Would it be easy enough just to swap the 3.1 top end onto the 3100 and go?

This was just a thought because I happen to have a spare hood and fender for my Lumina Coupe, so i could easily find the JY parts to fix the coupe and sell it, and have the sedan running and profit!

If this isn't as easy as I thought, then I'll just swap the motors between the luminas and junk the wrecked one.

Thanks for any insight/input.

[RobertISaar]

how far down will you be swapping?

you CAN swap the 3.1 heads/intakes onto a 3100 block... keep in mind it will basically be a LH0 with a roller cam and priority mains oiling, so expect ~140HP, maybe a bit more.

the 3100 combustion chamber is 28.6cc compared to the 3.1 being 26.4, 3100 has a 25.5cc dome in the piston, 3.1 has a 26.4.

in the end, you'll end up at ~9.03:1 compression, rather than the 9.55 of the 3100 or the 8.92 of the LH0. the good news is that you won't have to mess with the calibration to run it.

[91LuminaEuro]

Haha, so let me start off by stating I'm not looking for any performance gains at all, if there is a loss so be it. The main reason I want to do it is for convenience. It gets a motor out of my way in storage, and lets me keep my lumina coupe as is to fix and sell.

So if I take the heads and intake off of the 3100 and put the 3.1 heads/intake on it. I can swap over the appropriate accys n such and the motor will drop down in, plug and play? Thats basically what I'm looking to do. Is it that simple?

[RobertISaar]

probably. some of the 3.1 and 3.4 RWD guys drop the gen 3 top ends on for easy power all the time, basically the same process, just in reverse.

if you're on 60V6, ask and someone will surely have the answer.

[Dark Ride]

Is the 3100 still in the regal? Or if the 3100 is complete with harness, ECM, mounting hardware, etc. why mess with swapping heads and stuff. If you use the 3100 ECM you'll have the SFI versus MPFI. The only issue I can see (mind you, I'm about to go to bed, so take it for what its worth) is the new ECM won't be able to control the old tranny (unless you have/swapped the tranny too), will probably throw a code, but I believe someone drove their car for quite some time like that. You would have to do something about TC Lockup. Could run a manual on/off switch. I've thought about doing this for a while as I have a handful of old trannies. To me that sounds like about the same amount of work as swapping heads but with a better result, but to each his own.