The '72 455 I bought to put in my Cutlass Supreme could use some more compression... The 8.5:1 pistons will probably end up at about 7.6:1 based on my rough measurements (finally took the heads off last night).

I'm going for a very cheap build at this point, so if anyone has some usable 10.25:1 standard bore (4.125") pistons sitting around, I'd like to use them.

I'm near Decatur, IL, so anything within a couple hours drive would be best. I see new pistons for ~$300 at Summitracing, and I'm looking to be a lot cheaper than that. Let me know what you've got. THanks. Tom.

 

I am not machinist or an accomplished engine builder but, wouldn't pistons like that predicate a lot of money spent in the rest of the engine? It certainly won't end up being a "cheap" build. Correct me if I am wrong and I apologize if it turns out to be so.

 

Oldsguy,
i'm just looking for factory pistons from 1969 - 1970 that Oldsmobile installed in engines. Same crank design, same size combustion chambers (80cc i think). Perhaps the harmonic balancer will need to be changed if the piston weights are too different??? What other changes were you thinking?

 

Not sure, I just didn't think that high of a compression ratio was standard in '72. As I said, I may be way off base. I do think if you wish to increase static compression it would be easier to change the heads and leave the bottom end intack, unless it needs work anyway, but then, it will be costing you more money.

 

Dan, thanks for the input. I did measure my piston to deck clearance, and calculated my actual compression will be about 9.2:1 if I use the "10.25:1" pistons. So even though the advertised compression is pretty high, with a fairly think head gasket and pistons that are a little in the hole, the actual compression ratio won't be very high.

Right now I'm just trying to avoid paying for machining (unless its really needed) by using used standard bore high compression pistons. I plan a more thorough build in ~2 years when I can save some funds to buy new heads and pay for machine work.

Still looking for pistons if anyone has some they took out during a .030 or .060 over rebuild. Thanks. Tom

 

Yoooooooooo Hoooooooooo

Norm, where arth thou?

 

Looks like he wants used pistons. I don't have any.

Norm

 

I knew that I was saving these for a reason! I'll have to check my stash of "seasoned" parts to be sure; but, I'm pretty sure that I have a good set of factory high compression standard bore pistons. You are correct about the currently available head gaskets and using "high compression" pistons. It should give you decent power with pump gas. I'll let you know if I have a good set. Bob.

 

If you dot have any luck finding pistons. Look for a running motor out of a 68-70 88 or 98. The 88 would be a 9.1 engine (i did this with a 70 88 and the motor rocked) or 98 most likely 10.25.1. Im sure you could find one cheap. The 70 engine i bought cost me $500 with a performer intake on it. My current 455 i pulled out of a jet boat cost me $700 and i parted out the boat for over $500.

 

I'm sure I have a set also. Let me know.
You need to weigh each piston and rod from old ones to new ones. If they are only a couple of grams difference from each other. you are good to go.
Changing the damper will not make any difference. They all weigh almost identical.
You should at least ball hone the cyl's. That way you at least remove the glaze.

Gene

 

Thanks for all the input and contacts. I sent emails to 64Rocket and ROCKETMAN269V, and one other contact from a PM. Hopefully something pans out. Thanks again. Tom.

 

tom I PM'd you . got a set took out my 68 -98 455 OK ,pay shipping and they are yours .

rocwal
Dan B

 

What a deal. It is people like rocwal that make this site the best. It is the spirit of enjoying our Oldsmobiles and helping others that makes it work.

 

AMEN.
A lot of people would have tried to squeeze your wallet for all it had.

P.S.
If you only want 1, I'll take the other 7

 

An offer I can't refuse. Three cheers for Dan. Email sent.

Thanks everyone for the support and advice.

I have a question about the rings to use, but I should probably post that in the Big Block Section....