Neil,
Oh and there is also a 20 stamped into the piston top which I presume
means
20 thou over
Yes, it should. That engine was rebuilt sometime in the past.
Thank you for that information the problem that I have is that
this engine should be a 455 and if this is true then how can it have 350ci
pistons I would have thought that the 350 pistons would be too small for
the
455 bore
?????
Your question was this:
"Closer inspection today revealed a narrow v shaped notch in piston edge
which according to my csm says 350ci low compression could this be right??"
I said:
"Most GM products exported from the US had low compression engines. GM would
not guarantee what fuel quality would be available. Olds had a low
compression small and big block for domestic sales, and both were used for
export vehicles."
I simply said that Olds had both small and big block low compression
engines. Actually, in the 1965 shop manual, the piston needs to be installed
in the bore with the notch facing the front of the engine. The compression
ratio is indicated by how deep the dish is on top of the piston, the deeper
the dish, the lower the compression ratio. Your 455 should be configured the
same way. So should any 350 engine. Since I don't have access to the shop
manual you are referencing, I can't tell if Olds changed the way they did
things, or if it's a misprint in the shop manual, which has been known to
happen.
For 1965, the lineup of Olds engines was as follows. I'm positive that for
the year of your 455, something very similar was done:
(all engines have a head gasket thickness of 0.025")
330 with 10.25 to 1 CR, 2 bbl.
330 with 9.0 to 1 CR, 2 bbl.
330 with 8.3 to 1 CR, 2 bbl., export option
330 with 10.25 to 1 CR, 4 bbl.
330 with 8.3 to 1 CR, 4 bbl., export option
425 with 10.25 to 1 CR, 2 bbl.
425 with 9.0 to 1 CR, 2 bbl.
425 with 8.3 to 1 CR, 2 bbl., export option
425 with 10.5 to 1 CR, 4 bbl.
425 with 10.25 to 1 CR, 4 bbl.
425 with 8.3 to 1 CR, 4 bbl., export option
All I'm saying is your 455 could be low compression, depending on how it got
overseas. If you can determine how deep the dish is in the top of your
pistons, we should be able to tell you what the original compression ratio
is. I wouldn't go by the "V" notch.
Milton Schick
1964 442 Cutlass
[EMAIL PROTECTED]
