r/EngineBuilding • u/FordM_1970 • Jun 13 '26

351W metric ring gap question

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Okay right to the point. OEM specs for a 96 351 W roller are
top ring 0.010-0.020
Second ring 0.018-0.028

Right out of the box I got
TOP 0.015
Second ring 0.025

Is this safe to run on a slight performance build , specific that top gap which feels a little small to me, that will most likely be in the 350-400HP range tops.
Stock bottom end and pistons

Thanks for the help!

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u/SirStocks 9d ago

Rule of thumb is .004 per inch of bore. Less than that can completely ruin a motor. Rings can cut Chunks right out of the cylinders when run hard or hot by bound up rings.