1971 455 out of a vista cruiser any good?
March 5th, 2008, 02:22 PM
#1
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Join Date: Apr 2007
Location: hayward, california
Posts: 235
1971 455 out of a vista cruiser any good?
does anyone know the compression ratio of this year 455?
is it worth buying?
and i just found out my 350 isnt worth rebuilding the crank has to many deep grooves and a lot of thrust play and it needs a sleeve.
is it worth buying?
and i just found out my 350 isnt worth rebuilding the crank has to many deep grooves and a lot of thrust play and it needs a sleeve.
March 5th, 2008, 03:01 PM
#2
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,300
About 8.5:1. 1971 was the first year of reduced compression ratios to accommodate low-lead gas. The good news is that the G heads will have induction hardened valve seats.
The last 455 Olds block was cast in 1976. ANY 455 is worth buying.
is it worth buying?
March 6th, 2008, 05:23 AM
#4
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Join Date: Jul 2007
Location: Edmond, OK
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Changing to the pistons without dishes will increase your compression. Summit's rebuild kit offers the pistons with reliefs that will be higher compression than any smogger engine. They are cast, but they aren't 8.5:1 
March 6th, 2008, 06:12 AM
#5
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,300
All Olds big block heads have the same 80-ish CC chambers (except for the 68-69 D heads that have a designed chamber of 72 CC). Note that as-cast the chambers tend to run about 83-84 CC. The compression ratio is varied by changing the size of the dish in the pistons. The factory low-compression pistons look like soup bowls.
March 6th, 2008, 07:45 AM
#7
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
To accurately calculate the static compression ratio of any engine, the following values must be known:
Bore diameter, stroke length, rod length, deck height, combustion chamber volume, cylinder head gasket compressed thickness, and cylinder head gasket bore diameter.
http://www.rbracing-rsr.com/compstaticcalc.html
Bore diameter, stroke length, rod length, deck height, combustion chamber volume, cylinder head gasket compressed thickness, and cylinder head gasket bore diameter.
http://www.rbracing-rsr.com/compstaticcalc.html
Last edited by J-(Chicago); March 6th, 2008 at 07:52 AM.
March 6th, 2008, 08:09 AM
#8
Ca's Only Official OLZNUT
Join Date: Mar 2007
Location: Sunny So Cal
Posts: 509
These are the pistons out of my 400. I've never seen flat tops on an Olds until these. I was told these are the stock pistons. 400olds008.jpg
March 6th, 2008, 09:36 AM
#9
Old(s) Fart
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Location: Northern VA
Posts: 47,300
March 6th, 2008, 07:33 PM
#10
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Join Date: Oct 2004
Location: Southern CA
Posts: 2,212
You need to watch whose advice you are listening to.
No way to guess without knowing the piston specs, compression (pin) height in particular.
The internet is full of bogus information. You need to pay more attention to where you get your information.
Try it with the specs from your own engine.
Norm
No way to guess without knowing the piston specs, compression (pin) height in particular.
Norm
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