"Must have been only the 69 Camaro LT-1 "

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"Of course no camaro was every badged LT-1 but they had the LT-1 in them."

Not in 69 they didn't. 69 Z 28's were 302's still.

Stan-----

I believe that these numbers are casting/forging numbers (part number
for the forging/casting) and not actual part numbers for a finished
part. However, I think that we can identify them anyway. The forging
number 3942545 appears to me to be part of the series of part numbers
used for pistons for 1969-70 L-46 engines. For these engines the std
piston was 3942541, the +.001 was GM #3942542, and the +.030 was GM
#3942543. No other sizes were available.

The 3959456 appears to be part of a series of numbers used for pistons
for the 1969 special high performance 350 (LT-1). Of course, these
pistons were never used for a PRODUCTION engine, but they were sold for
quite a few years in SERVICE and as part of SERVICE engine assemblies.
They differ from the 70 LT-1 pistons inasmuch as the 69 were set up for
full floating pins; the 70 were set up for pressed pins. Anyway, for the
69 SHP, the std piston was GM #3959448, the +.001" piston was GM
#3959450, the +.020" was GM #3959452, and the +.030" was GM #3959454. It is also possible that the same forgings, including forging numbers, were used for the 1970 LT-1 pistons. These pistons were GM #3989048, 3989049, 3989050, and 3989051. If they're set up for pressed pins, then they're the 70 pistons; if they're set up for floating pins then they're the 69 pistons. I'd be curious here to know which ones they turn out to be.

There was likely more than 1 casting/forging number for each series of
pistons since, for instance, the standard piston would have to have a
different forging than the +.030". But, I do not have a reference as to
what the forging number was for each finished part number. So, I can't
tell you which bore size that these pistons were for. However, with a
micrometer, this should be easily settled.

I'm quite certain, though, that the casting/forging number that you
provided settles the issue of what application that the pistons are for
and those applications are as I have described above.

Best Regards,

Joe

Could it have been the 70 Camaro with the LT-1? And for that matter, what was different in the camaro that had the engine rated with 10 less hp at 360?

Hmmmmm, a little sarcasm here? Well, that's okay I guess. Maybe I should write a book. After all I am a legend in my own mind.

Anyhow: "Since you have all the answer, did the 69 z-28 302 have pressed or bushed pins and are you 100% no LT-1 where produced with bushed pins?"

Actually, I've only owned 2 Z28's, a 69 original paint, original motor, and a 70 turbo 400 which was less an original car. I never went in the 69 motor except to pull the valve covers and look at the casting numbers & dates the day I bought it. The 70 probably wasn't worth examining from a historical standpoint, having had a warranty block assembly early in life when a backseat passenger was rumored to have reached and pulled the shifter back to low at 100MPH on the interstate. Unfortuantely I sold them both when my storage crisis was about what it's back to now, so the access is gone.

Back to the question of the pins, I have no idea, but I wonder if you mean "pressed pins or floated pins" instead of "bushed". I've never seen "bushed" pins factory installed in an engine, but again, "I've never seen" is far from a statement that it never happened.

I actually have no idea whether LT1's were ever factory equiped with floating pins, but I've have GUESSED not if somebody asked me to guess.