Hi there,
yesterday I did a small investigation about my engine.
It was mentioned in the Spec Sheet (which comes with the car) that the engine is built up to Mondello Spec with 10:1 Pistons.(as well cam and Edelbrock Performer intake, and ported Heads)
The pre Owner didnt know, if this was done or not, so I grap a Endoscope from my work and figured it out.
I think it is now prooved that the built up use a 10:1 Piston.
Would realy love to know which brand (it´s only a guess what it could be)
Could clearly see the cross hatch along the bores.
A little bit carbon built up is allready there in the game.....





As I´m quite famliar to this business (honing) it looked quite rough to me, but anyway it was done ok.
The complete car is now proofed to the spec sheet and it works quite good.
I was wondeing why the engine bulder drop out of facbook, as I contact him to get more information about the built up. (ther was no need to do so, or that I want to blame him, that he did a bad job, everything is fine).

Anyway I will work along to my winterplans to get even more HP out of this 350.

Could you guess what Brand............it is a Guess :-)

 

They’re most likely the Speed Pro L2320F.
And if you’re have a regular Performer get rid of it and use the RPM. Much better intake for your application.

 

Maybe you are right but if I go on the summit racing site (for the SPeed Pro L2320F) there is a flat bottom piston without valve cut outs like mine........

 

Todde,
How long ago was the engine built ? That could be almost anyones piston but there are not a lot of choices for a 350 Olds. You cannot always go by the pictures on the Summit website I find them incorrect more often than not. Same with a lot of their parts specifications The Sealed Power catalog that I have says the L2320 is a flat top with no mention of valve reliefs so I doubt that is what you have.

 

Hi Bill,
yes you are right.Summit was the first site with pictures related to the guess, while searching in the WWW.
The WWW pictures are shown the SPeed Pro L2320F, everywhere,as Flat Top with no Valve prokets so I also doubt that these
Piston where used.
In the end they are different and my high hopes would be that they are forged....

In the winter I will demount the heads and maybe I got than more informations about them.

I think the rebuilt was done during 2013-14? Car was sold in 2014 in Ohio.
Didn´t know anything about the us pre owner, which is very frustating because I think that he loved the car as well.(so do I, my Happyplace)

The engine builder stepted out of facebook, as I asked him about the built up
but as far as I can judge, and I allready driven more than 3500km in only 2 month, everything is allright (so thumbs up for that).

 

Maybe back in 2014 but not today. Mahle, DSS, and CP make pistons for the 350 besides Sealed Power/Speed Pro. However most don’t want to pay the extra $$ for a real quality piston.

 

The pictures indicate a piston made with the valve reliefs as a part of the forging process and not added via flycutting so that may help narrow the possibilities; just my 2 cents.