The Stovebolt Site Forums The Shop Area Engine Shop 1954 gmc 100 deluxe 5 window truck with 248 engine

Hello to all. I am a new member to stovebolt and am looking for .060 pistons flat top for my gmc 248 engine. I have had 2 engines with cracked blocks and finally found a good block which had to be bored .06 over. I've been searching for pistons without any luck locating any. Egge pistons will not run a set until June sometime. What are my options? Could I use a 270 or 302 engine short block with all my engine components, cyl head, exhaust manifold, generator, starter, distributor, water pump, fuel pump, transmission and motor mounts, etc......? My new bore size is 3.778" with .990 wrist pins.

Thank you in advance
Gabeo

Welcome, please read the forum rules. References to parts wanted and parts for sale are not allowed in the garage forums. Such requests belong in the Swap Meet Forums. Thank you

Welcome to Stovebolt.com, Gabeo/gabriele

You might want to also join and post a Want Ad at oldGMCtrucks.com discussion board?

You could install 3/32" wall sleeves in the cylinders and re-use your standard bore pistons. The cost of the sleeves and the machining will probably be less than what Egge will charge for new pistons. Their prices are higher than the reproductive system on a tall giraffe!

Edit: I don't know of any reputable machinist that will bore an engine before having the replacement pistons on hand. You might want to consider doing the sleeve job and boring/honing the cylinders to the correct skirt clearance for your original pistons, but choose a better-qualified machinist to do that job for you.
Jerry

Thank you all for the reply, but it would cost me $1500 to sleeve and bore on the existing block. I've already installed the crank, cam, and front gear cover on the block. I would rather wait to find pistons to continue the build. Is there someone out there that may have them?

please visit the Swap Meet here on the Stovebolt page for your parts wanted/for sale inquiries.

hello; everyone. I
m still looking for .06 over pistons for my 1954 248 engine. Any help would be appreciated.

The 248 with flat pistons was a very short production engine. They were used in 54 and 55 and then discontinued. Finding any kind of pistons for a 248 is going to be a challenge. I could cut my losses and find a 270 or 302 block for which parts are available or find 248 with pistons in it that will work with just honing the cylinders. I am 77 years old and we had GMC's in our business when they were still current production. Installing salvage liners like Jerry suggests will make your engine like new. But even standard pistons are hard to find. We installed salvage liners almost 60 years ago, but if more than one cylinder needed one, be bought a new short block because they were still available then. Even if you find .060 pistons I would have the cylinder walls sonic tested. I would never bore an almost 70 year old engine .060 becaue you don't know how much corrosion you have from the water jacket. Salvage liners like Jerry suggests would fix this.

Have you considered checking with one of the piston companies such as Ross to price a custom piston? Last I heard, that option was around $600 foe a set. Just a thought if you are intent on saving original block.

Ive had some luck in the past with summit racing. MAH-S2243887.

I may have what you are looking for. I have taken apart a couple 248's and kept all the parts. I will check my stash in the next day or two. Odds are long that they are the .060 you want but stranger things have happened.

What is the compression height on a 248 piston? (center of the wrist pin to the top of the piston)
Jerry

I checked and mine are std and .040. Sorry, I was hoping for a better outcome.

If the compression height on those pistons is close to 2", a 261 Chevy .030" oversize piston can be adapted to fit.
Jerry

I'll check the compression height. Thank you all for your responses

I've got a brand new set of .60 over pistons from Patrick's that I bought for a 228 10 years ago that never got used. Mine are not flat top pistons, but the domed style. Swap to a different head and your in business. PM me if your interested and need more info on what style head to use.

Thanks,

A couple of questions: Does anyone know what engines will direct swap into my '52 Chev. 3/4 ton? Are all the push rods in a 235 the same length?

There were different sizes/lengths of push rods (pushrods) used in 235 engines between 1941 and 1962.

I think that there were different sizes of push rods in some car 235s vs truck 235s in the same year.

The Master Parts Catalog probably shows the different push rod lengths. Here is a catalog on-line that covers a lot of years.

First, you really should start a new thread and you’ll get better responses.

There is a Tech Tip for Swapping a 216 to a 235.

It appears the difference in the length of the pushrods depends on whether you have hydraulic of sold lifters. PG (power glide transmissions) used hydraulic lifters.