This is from the archives of the mailing list. It was written by a guy that worked in the Buick engine plant in Flint.
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in 1985 SPS and Kamax were Dual suppliers and their bolts were used
interchangably.
In 1986 SPS was was the sole supplier and we used up Kamax leftovers. I
don't want to slam a supplier but SPS had better quality that is part of
history. We used SPS until about '91. (I hav e the files if anyone needs
the exact date) When SPS decided to sell one of their manufacturing plants
we went looking for another vendor. Not wanting to get stuck with ACMe
bolts. It was then that Kamax got to be the sole supplier not in '85, not
because they were cheapest or better quality, but because they were the
only ones that could do the annular rings. Fear in our purchasing was the
driver for changing vendors.
SPS never did sell their plant .......
with out digging through my archives for the info I could be off time wise
a little.
I tried to look up ARP in our master fastener manufacturer catalog and
did not find them. Possibly they are a reseller and a major bolt company
really makes their bolts/studs?
They have never supplied rod bolts to Buick as far as I can find out. (Yes
we still call it Buick too)
SPS makes another aftermarket companys rod bolts.