The Stovebolt Site Forums The Shop Area Engine Shop a 270 for my '57 GMC

I have a couple of questions about this swap. I had a
pontiac engine in my '57 GMC,but sold it to a friend who's putting it in his '50 Chevy half ton. Now I have a '55 270 to put in my truck,but I have a few things to figure out.
I want to put an oil filter on the truck;there was no filter on this engine. Where do the lines connect? How much does it matter which line goes to which port on the filter?Can the 270 be set up with a full flow filter without disassembling the engine?
Will the 270 mounts fit where the V-8 was? I'm wondering if I have to change the crossmember to fit the six cylinder bellhousing. Also,this engine has a 11" clutch and was in a '60 CHEVY C-60.Is this clutch,flywheel and bellhousing different from a pick up set up?
The draft tube goes up into a chamber with a filler cap and a lid held on with two bales,like distributor clips;under the cap is a round filter cartridge. Any idea what that's for? Any idea what filter it takes? I rinsed this one out with diesel and blew it dry,but I'd like to replace it if possible.
Will this 270 fit in place of the Pontiac V-8 without having to relocate the radiator or crossmember? It has a single bolt through the front mount,with a round biscuit about 1-1/2" thick and about 2" diameter;that should line up with the front crossmember,right?
Sorry for all the questions;just trying to get my ducks in a row before I start putting it all together.
Thanks for any info you can give me.
Speed

The filter is only for a crankcase vent, if you wish, seal the draft tube and put on a PCV valve, or O.K. to leave as is, only problem would be if the engine has lots of blow-by oil will drip from the tube called road draft tube. The single point front mount is only to be used with the bellhousing mounts at each side. If you don't have these side mounts the engine will move sideways and tear off hoses, wires etc. All early truck bellhousings come with the mounting holes for the motor mounts. The GMC 270 has lots of torque and needs to be restrained from a lot of movement. Great choice of engine I think. I had a 270 in a '39 Chevy years ago and it was great, but broke many transmissions, early Chevy transmissions aren't very strong.

was this originally a v-8 truck or a 6 cylinder. the rear crossmember should be the same for 6 and 8 configurations unless the truck was a hydramatic equiped truck. If I recall on the 57 gmc the radiator and front clip mount to the front crossmember. for a factory v 8 the crossmember was the same but there was an extra plate riveted on for the v 8 mount. If you are using the stock gmc 6 front motor mount... they are really hard to find. Nobody reproduces them to my knowledge. you may be able swap a chevy timing plate on the engine and mount it to the crossmember with a chevy motor mount.

Yes the '55 motormount with the one bolt should mount to the '57 crossmember. You would only need the timing cover mount plate if you were putting it in an earlier GMC. I'm assuming the V8 and 6 used the same crossmember as I don't have a V8 one to look at.

The 270 came from the factory set up for a full flow filter. At oldgmctrucks.com you'll find a plumbing diagram as well as a wealth of info on the engine including info on the various draft tube/pcv set-ups.

cletis wrote: "The 270 came from the factory set up for a full flow filter"

The 270 came from the factory with a bypass filter. The 270 is a full pressure engine and can be converted to a full flow filter with a little help. There is a tech tip somewhere that shows the procedure similar to the way "California Bill" wrote about it in his "GMC Speed Manual". Basically drill a hole in the block, tap and plug.

The Advantage of this set up is that the oil will go through the filter, and "clean" oil will shoot trough the main bearings passages. The way the factory set it up was that clean oil was pulled from the engine, filtered and then essentially returned to the oil pan to mix back with the "dirty" oil.

Interestingly enough I have heard that some of the old timers would drop a role of toilet paper in the filter canister of the bypass filters. never had the balls to try that myself.

Found the link to the tech tip. It is on the inliners site.

www.inliners.org/

OOPS! Sorry about that.

Thanks for all your help! I asked about this on the GMC trucks forum and those guys were a little "abrupt" with me. Got a little good info and several posts asking why I'd get rid of the original V-8 and go to a 270. Hey-the truck is no longer pulling a 7,800 pound trailer so I can live with a bit less power,and I LIKE A SIX.
BTW-at the same time I put this 270 in,I'm installing a Saginaw 4 speed;I found out it'll cost me $40.00 to shorten the front section of my driveline,but then I discovered a front half I pulled from a '71 Chevy van with a 292/3 speed stick. The yoke fits mt 4 speed,and it appears to be about a foot shorter (I measure a 10" difference in length between the SM420 and the Saginaw.)
I also got some measurements from the crossmember and the bellhousing. The crossmember has 2 sets of holes,one set is 17-3/4 inches apart;these are the ones I used with the V-8. There were another set 12 inches apart,I assume for the "light duty" 270 with the small clutch. The spacing of my 270 bellhhousing bolt holes is about 15-1/4 inches,(I think that's what I measured) so it looks like I'll have to punch a couple of holes in the crossmember.No biggie.
Does anyone out there have a pic of the throttle linkage for a 57 with a six? If I can see how it's supposed to work I may be able to duplicate it.
I'm thinking really seriously of changing to a cable assembly from a chevy pick up.
Anyway-rather than questioning my motivation,you guys jump in and help. No wonder I love this site!
Speed

Okay; I got my flywheel back from the machine shop tonight,so tomorrow I can put the clutch and tranny on the engine and set it in place. I have most of the installation issues resolved,now it's just a matter of removing the V-8 exhaust pipes and setting a 6 cylinder dual set up in place,swapping the front driveline section for the 10" shorter one (OH-I still have to order one of those Heavy Duty carrier bearings from Inland Empire Driveline-$109.00)
Email 'em for more info at [email protected]
I'll have to re-drill holes for the rear crossmember mounts,these are right between the six and V-8 holes.(I can only assume the different width is due to having the bigger clutch and flywheel than the pick up sixes had.)
I ended up using the throttle linkage from the donor truck;it has the hand throttle provision and onlt required drilling 3 holes.
Anyway,hoping to have the engine/trans. installed this weekend.
Speed

I got the engine set in last night. The front mount was no problem;rear mounts will needa little work. I decided rather than removing the crossmember and re-fitting it a half foot back,I'm going to cut some plates which I'll bolt solid to the bellhousing mount holes,and bolt at the other end to the crossmember rubber mounts.That'll take care of the difference in width of mounting holes and the difference in distance from front mount to rear mounts. Got the driveline in;I used the stock GMC driveline from axle to carrier bearing,used a front piece from a mid 70's chevy van with a 292 and 3 speed stick. I had to cut about 2 inches off the splines but other than that,it makes a bolt in driveline for the 270/Saginaw 4 speed.
I'm planning to use a Datsun hydraulic clutch,since I have one on the shelf;I'll need to have a line built for it once I get the cylinders installed. Once those issues are handled,it'll just be the usual things;belt,hoses,oil filter,wiring the engine,tune up,throttle and choke cables,etc.
Oh,yeah,and an exhaust system of some kind.
Speed