The Stovebolt Site Forums The Shop Area Engine Shop 270-216 Swap

I was wondering what would it take to put a 270CI motor in my 1949 Chevy 3100 with a 216CI engine in it

270 out of a 1959 GMC

The 270 is slightly longer, about 2" I believe. You'll need to relocate the front motor mount, and probably move the radiator forward a little.
Jerry

X2 on what hotrod said. The late model 270 engines (1955-1962) have a "horseshoe" front engine mount that bolts to the sides. If you were trying to bolt this 270 into an earlier gmc pickup, the mount might give you some problems. You will likely have to fabricate a new front mount plate on your crossmember. If you stick with the horseshoe mount, it will be next to impossible to find the engine mount cushion. There is another option for the cushion mount...
Simply swap the front timing plate from the 216 to the 270. It is not as easy as it sounds. You will still likely ahve to fabricate a plate for the crossmember to bolt the engine mount to.

There might be an issue with the generator bracket to. My 59 gmc 270 had a bracket for a long delco 12 volt generator. This bracket should also work for a 6 volt generator. I have seen many 270 engines with a short generator bracket that will not work with the 6 volt generator. You could always convert to an alternator.

John

I did this swap a long time ago in a 1951 Chevy. Don't think there is much difference between the year models.

The biggest issue I had was the radiator had to be moved forward about 1 1/2 inches (if memory serves me right).

I used a 270 out of a 1958 GMC

I don't remember any big problem about the front mount other than having to move it forward so the mount on the front of the engine sat on the cushion. But this has been 30 years ago.

I converted everything to twelve volt so didn't have any bracket troubles.

Wow, now you guys have me confused. I've got a 58 GMC and over the years a lot has been changed on it. It originally had a 270 but it must have gone by the wayside long ago because when I got it there was a 235 in it. Looks like the 235 was about 2" to long for it because the front mount is on top of the front crossmember, not in the holes that are in the bottom lip of the crossmember. Could this maybe have had a V8 in it originally? VIN# 101 PS6774A
10 = 1/2 ton
1 = 116" wheelbase
Blank = inline 6
P = Pontiac
S = 58 59

From the ID in LMC catalogue

Maybe I'm missing something but I'm going to keep going and make me a driver out of this anyway using what I have. I like the Sanford & Son look.Larry

The 235 six is about 1 12 inches shorter than the GMC sixes. They used the timing cover mount on the 235 to set the engine in instead of using the correct side mounts for the 235.

Some Canadian GMS may have had the 235 instead of the 270. My bet is they would have used the side mounting holes on the block so the mounts would line up with the holes in the frame.

The 270 GMC six may have had the side mount system too. maybe someone can chime in that knows more about that.

GMC's mounted the radiator on the front side of the core support, Chevy's mounted it on the rear-same core support. If you don't already have a 270, 302's are also available, some price mto rebuild.

The 1955-1959 gmc 6 cylinder motors were a side mount motor. That was explained in my post above. The front mount or yoke only used one bolt through the crossmember. The cushion had an oval shaped lip and a peg to positively locate it into the crossmember. Chevy and GMC trucks used different front crossmembers. The 58 and 59 gmc front crossmember almost looks like a chevy crossmember. The 55-57 GMC crossmembers are completely different from the 58-59 gmc crossmembers or the 55-59 chevy crossmembers. I suspect Canadian GMC trucks would have used the chevy front crossmember.

In that case if I had a GMC frame the 235 front mount would be short of sitting on the lower lip of the front crossmember. There is no sign of this truck using the side mounts to frame, no holes in frame. I bought the 235 rubber mount and the shield that is available and made the remainder of the mount. It sits on a plate welded and bolted to the cross member, just foward of the original mounting holes in the lip of the frame on top of the crossmember. Seams to be working nicely so far. I'm fitting the front sheet metal now so I can put me a backyard paint job on the cab. Can't wait for the first ride around the neighborhood odd ball engine or not.Larry

Brown, I just did the same install. A 1955 270 into a '38 Chevy that had a 216. The GMC has a single bolt front mount that is 1 1/2 inch closer to the radiator. Moved the radiator to the front of the 'U' channel. It worked nicely for me and I drove the frame around the neighborhood.

Wayne67vert was the '38 chevy a truck or car? I am contemplating the same swap with a '37 1-1/2 ton. Did you have to alter the radiator or the front crossmember? Did you use the original bell housing? Any info would be greatly appreciated!
Thanks!

It is the truck in my sig line and in the gallery. I moved the radiator to the front side of the 'U' channel of the radiator support.
I used the same crossmenber. I just drilled it to match up with the front motor mount.
I also changed the transmission, using the 3 speed that was mated to the motor when I bought it. So I used the newer bell housing. I had to make a new bracket to support the brake and clutch pedals. bracket
hold down the control button and push the + key to enlarge the photo.