.040 pistons

[Guest musclecarfan65]

hello. i just bought a complete set of .040 federal mogul sterling pistons with bolts (but without piston rings) for a "gmc 401" for very few euros. i just wanted to ask the forum what your experience / opinion on these pistons is. best regards, dirk.

[RivNut]

What's the diameter of the pistons? Are they for a Buick? The Buick pistons would have a large dome on the top, and the wrist pin would have to be a certain distance from top of the piston and the skirts will need to have the correct configuration. Many variables make only one piston work in an engine.

[NTX5467]

I hiiiighly suspect you have purchased a set of pistons for a GMC 401 cid V-6 truck motor. This was a GMC Truck and Coach Division motor ONLY and saw NO car uses. Putting "GMC 401 V-6" into Google came up with a good bit of information on the engine and its variations. The "and bolts" comment would lead me to believe they were for an earlier-design truck motor where the bolts went through the wrist pin end of the connecting rod to keep things "assembled" there.

If you have them in their original boxes, you might reference the Sterling/Silvolite website to see what that number's vehicular application might be.

You might have purchased more of a "piece of history" than you suspected, just probably the wrong piece you weren't looking for. In earlier times, there were NO GM Corporate engines as each engine had its own originating division (which they were proud of), including GMC TRUCK (which did use some GM car engines from time to time in its earlier and later history as a separate GM Division).

Regards,

NTX5467

[Guest musclecarfan65]

it is set of 8 pistons with bolts. the original package says: skirt size 4.22675 +/- 0.00025 inches. 8 ea. 69P. .040. size point .06 from bottom of skirt. minimum clearance .0005. GMC 401. the number on the far right side of the bar code is 98253 RED.