Projects 1954 GMC Series 1

Cool… they look the best but actually flow the worst. You can tell by the exhaust needing to exit at 90*. They however miss every aftermarket intake. Under no way will my son take his off.

 

@jimmy six is that a trio of tri BBL carbs???

it was more of hearing he had 7 sets left a few weeks ago and the big swap meet is next weekend figured id swing by and see if he still had any and he had 2 sets left. His originals he wont sell and one set left of the repops. So $500 poorer i left his humble little shop. Lol.

They cant however flow any worse than the Clifford ones that came with the 6=8 intake. Lol toothpick tubes. Lol

 

The Holleys are 1960 Mercury 280 cfm on Offenhauser adapters to the early 3 bolt base which came with every Howard 5-2 manifold I’ve ever seen. These are set as progressive but they were originally on a Clifford tubing intake as straight linkage.
When I was building an engine for the coupe, I gave him because he was willing to put it back on the street, we started racing in 1975; my son asked me to put everything I could from the original engine possible that I still had. The block, rods, rocker arms, and carbs were about all I could. The Howard 380 cam was just too big so we used a Howard 298. Ross pistons for lower compression instead of the Arias 12-1, and a 270 H head that had not been milled. The balancer is a 292 from Tom Langdon along with one of his street ignitions. All of ours had the vacuum advance removed. The Nicsons and the Howard intake were never raced by us and were acquired at swap meets in the 80’s.

We still have the Clifford long tube headers I bought in 1975 for pickups which were perfect for all the years we raced the car. I believe they were designed to work with the 3-2 tubing manifold mentioned above. The intake runners were about 10” long. I had it chrome plated in 1977 and we continued to use it to 1996 with those same carbs.

 

Loaded and ready for Monroe Swap Saturday. Still have the shop trailer to load but i am loaded with round one of parts o wont be using. Keeping the 248 for now and will be stripped for parts mostly valve train. Sad they are not worth much as ive got an extra crank, cam, head in addition to the entire 248. But there is always next years swap meet.

But helping clean stuff out, i was given these fog lights for my truck. Just have to sort how to make them 12v. haven’t seen if the lens is separate to make things easy.

Should fit in nicely with my Farmers “Saturday Night Special” I'm going for.

 

Well a bit of a disheartening turn tonight. I got my Best Gasket kit in the mail, so I figured id finish getting the block ready. Needed to pull the cam so i could replace the gasket behind the timing plate. Started off finding no gasket behind the retainer and thats when things went south. After carefully removing the cam i noted some unusual wear on the rear most bearing surface on the cam. Fingernail test failed. Looked at the bearing and it looks like someone beat it with a screwdriver. Went up the line to the front and yep all pretty effed up. My gut tuned over. Grabbed the ratchet and popped a rod cap. Crud. Block is a D Block so it has standard mains and rod bearings and it has 10 under bearings and my guess was the crank wasnt turned. Im borrowing a micrometer tomorrow to verify. Put that back on and pulled a main even worse. 10 under bearings as well and scored badly. So off with the head. And by now I wanted to cry. Recessed valves to start, had a decent gasket on it though copper rings around every water and oil passage. But the one cylinder i saw in the borescope is really bad and very etched. Someone added their own oddball stampings to the piston and block on the deck as well.


At this point i have zero idea what i am going to do. Have to motors that meed rebuilt and seems like Egge is about the only company with parts and no oversized pistons.

Enjoy the carnage photos.


#2 bottom end rod bearing

Rear most Cam Bearing

Second to last cam bearing

Second Front Bearing

Front Bearing


Rear Cam Bearing Surface


Head with questionable valves


#5 hole with deep etching



Block


#2 main cap bearing and crank



specs



sigh, some nights you win and some nights you crash and burn. Should of checked this motor more before spending $2500 on everything I’ve accumulated including the transmission.

 

I'd assemble it and run it while looking for a replacement. You said you drove the wrecker it came out of and it seemed fine.... Let it fly.

 

I might have to do that. At a minimum new cam bearings. Just sad as this one was suppose to be a low mile rebuilt motor. Now im glad we pulled it from the truck i got it from as it would not of lasted long at all in a 2 ton truck. Now i have 2 motors on the floor in pieces. Lol. Odds of finding another 270 or 302 in good shape is slim to none. May find a 250 from a Nova but then none of my parts fit.
No clue where im heading with it now. All the money ive invested so far.

 

Dawned on me looking at the pics on my big screen. They drove the cam bearings in with a screwdriver. Rolled edges, sideways strikes. So all that trash went thru the motor and wiped it out. Ill have to cut open the oil filter.

 

That sux.
GMC parts are fun to find. I almost bought a 270 but decided I’d just keep the 235 someone put in my gmc.
There’s been a lot of old engines that got an emery cloth polish, a hone and new rings and bearings.

 

As a kid I bought a '65 Polara that was worn all the way out by the CHP. As Ant-Knee said, emery cloth polish, hone, new rings and bearings and it ran great. Well enough for me to total that car and lose my license. But I digress. Touch it up, slap it together, lap the valves if you need to and run it while you ponder your options.

 

The plan now is to finish tearing it down, hot tank the block, inspect it, and at a minimum get all new bearings. Polish the crank and hope it stays in spec as i seem to only find 10 under bearings nothing more. But i have the complete 248 and another small chamber head and another cam and crank outside of thr 270 and 248 blocks. Hopefully make one complete good motor out of all the parts. Still gonna sting. This was supposed to be a low mile motor. The previous owner drove it back from Oregon this way or it happened along the way. Hard to see in pics but the oil filter is very sparkly.

 

Is this legit?
https://www.ebay.com/itm/125233980869

 

Worth sending a message to him. Egge is a bit cheaper but all they seem to gave is 10 unders.

 

Tonights carnage. #5 hole is definitely the worst. Tried some grey scotch brite pad and oil and didnt touch it. Red pad didnt touch it either.

All the rod journals are .006-.010 out of round measuring right at 2.300”+/- .005.
Mains i haven't measured yet because i cant see how to remove the oil pump from the block with the funky bolts holding it in.

But all 6 piston compression rings were all lined up teo had the oil scraper rings also in line with the gaps of the compression rings.

so enjoy the show! Lol time for a shot of Scotch for me.

 

Little side note on another project i just wrapped up where i spend my days. sadly not necessary HAMB material but it does have a hopped up 52 8BA Flattie. But mated to a C4 now with a $$$ TCI frame now under it.

 

Perfectly fine here, just don't show the M2

 

I've seen worse! Does look like new bearings, probably not a "clean" rebuild. Get the block honed and cleaned, new cam bearings, and put some cast rings in it. They'll straighten those bores up. Does northern auto parts not have a rering kit for it?

 

I havent checked Northern Auto. My machinist wants to clean an inspect the block first. Has a fairly good ridge at the tops of the bores as well. If i can find them I wouldn’t mind punching it out a bit.
Further inspection i doubt the head was touched when it was rebuilt. So thats on the list as well.

 

Pistons are not normally Knurled from the factory right?

 

No.

And also rings will move from where they started at, to where they end up at over time.

 

Just totally bizarre they all ended up in a line.

Might of found some 20 over pistons and rings.

 

And the block is standard bore?

 

D Stamp block so its a +.005 overbore with originally standard mains and rods

 

So the intent would be to have a shop take it to .020 from standard, fit things, etc. ?

I’m not questioning you, just trying to figure it out

 

Yep. Or to whatever oversized pistons i can find. Found a few domed piston kits, i assume to raise compression.

 

Or to bring it back to standard compression ratio, if pin heighth is higher on the piston. Many rebuilder pistons are made to compensate for the block getting shaved and trued up.

 

Found a good casting number chart and gathered this info

Using the ID chart i found an few issues?

Block is a 2434003 55-63 270 with side motor mounts
Head is 2194819 55 270
Cam is 2193486 which i had to look elsewhere and is for a 228???
Crank is 2342204 which is a 52-54 302?
Rods are 2341204 late 302
Pistons are 2341506 cant find info

Spare crank 2194570-248
Spare cam- 2193486- early 228

So im guessing my supposedly low mile rebuild is a find anything and make it run rebuild.

 

Cams should be iron? Easier to regrind. I just had a steel one done. Grind, nitride, straighten and polish. Head is the small chamber one.

 

Never have i been in such a fix. Lol. Amazing how parts for these seemed to have just vanished. I even had a pleasant chat with Mr Langdon even he doesn’t have any leads. . I guess i see what my machinist says. Im not after a hipop performance motor but a good weekender and one i can trust if i wanted to drive it 500+ miles on a trip.

 

Rock Auto still list rod bearings, cam bearings.