One factory piston - 1970 455

A local friend needs just one factory piston from a 1970 455. The part # is 1231733. This is a one-year only piston as the 71/up 455 pistons have a deeper dish/lower compression.

Thanks for any help.

 

James,
I had some but not sure where they are at but I will try to look.

 

Thanks Nelson.

 

I have some. At least I think they are right. Came out of my brother's 70 455 GS car. Had about 60,000 miles on them as I recall. Have to look at pn

 

Got a few here also

 

Thanks to all you guys. He wants to now replace 3 pistons in this motor, so if someone has 3 spares without breaking up a set, I would be interested in purchasing them.

 

I'll check..I should...my machinist broke a few trying to get the pins out and they are prone to cracking anyway...would be surprised how many running engines have cracked pistons on the skirts

 

His car broke the ring lands on # 1 in several pieces and it was burning a ton of oil. He inspected the others and decided to try to replace 3 of them. He was able to get the pin out of # 1 without breaking it, so hopefully he can do the others as well.

 

Sounds like the same problem that I have encountered in a number of Olds high compression engines, both small and big block. The gasoline available today cannot adequately support the compression ratio of these older engines. The result is damaged ring lands/ blow-by/ oil consumption, etc. He would do well to replace all of his pistons with forged units in my opinion.

 

Thanks for the info - I'll pass it along. He was hoping to just get by and replace only what was needed and not have to rebuild the entire short block as the car only has about 60k miles. Are there any 'off the shelf' forged pistons available these days for a '70 455 to keep the compression up without decking the block (numbers matching engine)?

 

I have 6 of them. Still pressed on the rods from Buick. As I mentioned earlier, as I recall about 60,000 miles on them. I parted the car out maybe 45 years ago! My experience with many of these engines over the years taught me that the factory '70 pistons were generally good up to 90-100k miles under normal use and after that you were on borrowed time before they would start cracking around the ring lands and compression goes away, oil consumption, etc. I guess $100 for three rods and pistons plus shipping.

 

Try heating the aluminum pistons in a oven. The aluminum will expand further than the steel wrist pin.
Give it a try. Maybe all the pins will come out without breaking the piston. Vet

 

Keeping the compression up is probably not a great idea with today's gasoline; however, when replacing the factory steel shim head gaskets (~0.017" compressed) with aftermarket, such as Fel-Pro (~0.042" compressed), the net result is a drop of about 0.6 in compression ratio, which is more tolerant of pump gas without a noticeable loss of performance.

 

back in the day, about 50yrs ago....the nhra build for 70 stg 1 pistons were flat top even though the oem's were dished like yours.
all manf's lied to nhra. my 73 stg1 came with the deeper tops.......but the nhra build for 73 stg 1 is what you have.
i have .010 over pistons in my 73 engine. now nhra 73 buick piston build is back to oem deep dish.