Inliners International Forums General Discussion Engines Where to find piston and rods for 270 GMC

In the middle of a rebuild for my 59 270 GMC does anyone still make rods and pistons?

You can have the rods reconditioned and Egge may be a source on pistons...

I am most worried about the pistons right now, no idea what I need for a size yet.

I also can not find any on the Egge website.

The 3.78" bore is not that unusual.
The problems:
Which combustion chamber do you have (head casting number will help), some need a special dome config.
The compression distance is very tall, not modern, no way to fix this.

As CNC stated, the rods can be rebuilt. Cheap pistons may be hard to find as all the old ones are consumed. New pistons can be made custom order. Much pricier but overall a much better option for weight of piston and better rings. 12Bolt is a dealer for Ross pistons and can get them made. Usually 5-6 weeks wait.

I heard nearly $1,000 including shipping

I doubt it would be 1 K, but would bet them to be 7-800. Price depend on lots of things. Flat top, dome, valve recess's, availability of rings ect.

I can not remember if it was here or on the HAMB that someone used longer rods and off the shelf pistons. Also save 1.25 lbs per cylinder. It may have been for a 302 but 270 I think. All GMC rods are te same except some have a bigger pin and there is a difference in the width of the tab that holds the insert on the crank end on some of the newer engines. 8" Hudson rods will work using a Mopar bearing. 270s can go out safely to almost 4" bore and some have gone all the way to 4". My 270 is a '57 and has the newer style small port head. Just fine for the street. Anyway there might be a rod that opens up piston choice.

Indeed, they were all domed and different shapes. I got these photos from the old Patrick's site:

Ron Golden from here on Inliners. He used a shelf 400 Small Block Chevy piston on Hudson rods....

Here's the thread - images are in tact. Inliners Hi Performance post circa '13

Thanks for the responses guys, the head casting number is: 2194819
Im not going for a super hot build maybe a little hopped up with a intake and cam but nothing crazy. And with the gas prices needs to use 91 octane

400 Small Block Chevy piston: 4.125"

I guess my next problem would be finding bearings for the crank and rod now. I saw someone still makes cam bearings
Any recommendations for a cam?

W/r/t cam
What does it weigh
Transmission
If AT, what stall speed
If manual, what 1st gear
Axle ratio
How much slow traffic
What static CR

Ron was using a 302 bored to 4.125", so the 400 SBC piston worked out for the 308 Hudson rod length.....

Just a stock 59 GMC 100, not a ton of slow traffic but I do not want to effect drivability to much. I plan on taking it on day road trips at about 55MPH, I plan on a SM319 overdrive but right now it has the stock Sm318

The real problem that has plagued the Stovebolt's and GMC's for a long time has been replacement lifters. There was a period of time not terribly long ago, there was none available. As for the camshaft, you may end up having to have yours reground. Some cam companies such as Oregon Cams can also reface your lifters provided they aren't worn too badly.

Here is Ron's post from 2008 describing his GMC 302 build......Also, Hudson rods, not Packard!




Beater,

321" GMC (+0.125")Block is filled with HardBloc to water outlet.
308 Hudson rod (8.115" C-C)
0.880" Pontiac pins, 84 grams lighter than GMC.
JE 11.5:1 piston (400 grams lighter than GMC)
Stock main brgs.
CR90P rod brgs ( 1940-1950"s Chrysler)
2.02/1.60 SB Chevy valves
#983 cylinder head, ported. 264 cfm @ 0.600" lift
Dema Elgin did the cam based on everything else in the engine.
I wouldn't consider anyone else grinding a cam for this engine. Pulls like a freight train above 3500 rpm.
Aluminum roller rockers we made. (1.85:1 ratio on a 1.00" shaft)
I saved 1.25 POUNDS per cylinder with the piston/pin/rod.
Bearings look good after 20 pulls on the dyno and 6 runs down the strip.
Smith Brothers Pushrods, Bend, Oregon. 5/16, 0.125" wall. Beautiful work and delivered on THE day promised.

Yes Scott, That is the one I was thinking of. I wonder if Ron is still running it? I bought 2 sets of Hudson rods after that for a 302 I may build someday. I wonder if there is a piston that would work in a 270 with the Hudson rods?

The Hudson rod needs a piston more or less 1.115" shorter than OEM. That CD length may exist, but not be something with a life expectancy.
Deck height (to .000") = 50% of stroke + rod C-C length + piston compression distance.
Piston to head .035" including compressed head gasket thickness.
In a quench chamber "work with" is critical to no less than .035" and no more than .060" P-H. below that crashes the head when hot, above that has minimal knock suppression.
I can't imagine how much a high compression dome for a 400" SBC does not resemble a GMC chamber.

I believe he sold that engine. Talked with him at a swapmeet. Also think at that time he was working with a turbo 4200.

I brought this up at our chapter meeting today. One member may be able to chase down what you need when you know what over bore you need. He had a good supply when he sold his shop but thinks they went to Salt Lake City.

Thank you! It will be going to the machine shop today or tomorrow, my next problem is bearings, is there .10/.20/.30 available? I belive cam bearings are the same as Chevy.

Welll Im not sure the block is saveable I�ll attach pictures of crank caps and the block crank surface. https://imgur.com/a/SPSo04b

OK, It spun a couple of mains? That can be fixed but may not be cheap enough. What we do on these old engines doesn't always make sense. Sometimes it is just the challenge/fun.

It may e time to make some choices.What do you want for your '59 to be? Do you want it to have it's original class or be a modernized cookie cutter driver? Opps, I may have let my bias creep out. I wish you were closer.

I really want to keep it original as a 59 GMC Ive also thought about tracking down a 336 GMC to put in. The truck actually has a pretty good running 62 235 that needs some carb work and a rear main seal pretty bad. Is there a way to put a rear main in without pulling the engine?

Yes, you can do that. I evolves a puller like Chinese handcuffs.

Well I guess I have decisions to make I can get a good running 336 GMC motor for 1300, or a Fresh block with pistons and crank for my 270 for 1000$
The 336 would be cool but technically not "correct" for my truck.

As far as I know there was not a 336, A 236? 236& 256 were limited production short deck engines. While a 248 would not be a bad choice. A rebuilt 270 Shortblock for $1000 isn't a bad rice if done well. I doubt if you could redo yours for that + time.That's where I'd go.

The 336 is a specific GMC v8 made by Pontiac base on the 370/389 was only used in 58/59.
From what I understand the block is not assembled on the 270 but it has all the parts to be and I could slap my head on it.

Well heck, the 336 wouldn't fit here. If you would be OK with a V8 a brand new crate motor is hard to beat. Not a classy though.

Is the 270 close enough that you could give it a good inspection before you buy it? Is the price negotiable?
It would give you a chance to make the most beneficial modifications while you assemble it. #1 better intake, #2 better exhaust, #3 a cam more suited to your use. A totally stock 270 may be best suited.

I went to another machine shop today and he says he thinks its repairable but I might need a new crank. So looks like Im going 270 after all, im sure someone on here could locate a crank if I need one, I will for sure need a 1 rod cap. And 2 rod nuts, a cam, lifters and the hard parts bearings and pistons.

I helped a young guy here who was planning to put a GMC in his '49 Chevy pickup. I helped him locate a 302 & a nice 270 along with intake, carbs, headers & cam from a friend's stash. He was a military guy and put in for a transfer to Texas. He took all the Jimmy stuff and sold it back there and put a 350/350 in his pickup. You can't trust young guys.

The only cranks I have are the 4 bolt flywheel style.

I am sorry to hear that, not all young people are like that but a lot can be. Ill update this thread when I know more from the machine shop.

It was said in jest. He was a good guy bit in over his head. He liked my pickup. I let him drive it so he could compare it to the 216 in his '49. It would have been fine if had stuck around but once he left here he he fell under the influence of regular car guys. He really did not understand what treasures had been nearly gifted. That has happened to me a few times but it has worked out just as often and I still have more than enough junk.

Block is good! He says go for 40 over pistons if Im having them custom made what should I go for like 60? He said anything 30 over or above. He thinks crank will clean up also. When Im buying pistons is there a way I could bump compression up a little to make some power? I will call eggy tomorrow after I see what you guys think.

If 30 over will do it right. Do 30 it will leave you more in the long run If you ever needed to do it again. But if you never plan to rebuild again Take the 40.
Just my2cents

I agree with twisted6 if it will clean up at 30 do it. 30 years from now you may want to do it again. By then you'll be able to print pistons at home.

If it were me I would pin the machinist down to where it will clean up. I would have the pistons made and hand them to the machinist before he bores the cylinders or at least do a cleanup bore to fit the pistons. With the '59 270 head flat top pistons are best. Shaving the head & decking the block can add compression. Do your homework and check to see if this has already been done to your head & block. Best Gasket makes a very good gasket set & the best rear main seal I have ever used. Bearings should not be a problem.