[pippintook]

I have Pontiac 400 +.040 Keith Black KB133 Hypereutectic Pistons (part #KB133). 4 pistons have identical valve reliefs. The other 4 pistons have identical valve reliefs.
This indicates to me that the pistons must be installed with the correct orientation in the correct cylinder.
.
Yet, there are no instructions included with the KB133 indicating piston orientation for a Pontiac 400. I also checked KB's web site and only see a piston orientation diagram for SBC and Chrysler Wedge.
(see http://www.kb-silvolite.com/article....n=read&A_id=10)
.
Using the SBC piston orientation diagram and applying this to the Pontiac 400, I have 4 "left exhaust pistons" (this is KB's
terminlogy) and 4 "right exhaust pistons".
The SBC instructions state "left exhaust pistons
go in cylinders 1-4-5-8" and "right exhaust pistons go in cylinders 2-3-6-7".
.
Does anyone know what is the correct piston orientation and corresponding cylinder for the KB Hypereutectic pistons ?

PS I am uploading pics of the pistons

[pippintook]

I have Pontiac 400 +.040 Keith Black KB133 Hypereutectic Pistons (part #KB133). 4 pistons have identical valve reliefs. The other 4 pistons have identical valve reliefs.
This indicates to me that the pistons must be installed with the correct orientation in the correct cylinder.
.
Yet, there are no instructions included with the KB133 indicating piston orientation for a Pontiac 400. I also checked KB's web site and only see a piston orientation diagram for SBC and Chrysler Wedge.
(see http://www.kb-silvolite.com/article....n=read&A_id=10)
.
Using the SBC piston orientation diagram and applying this to the Pontiac 400, I have 4 "left exhaust pistons" (this is KB's
terminlogy) and 4 "right exhaust pistons".
The SBC instructions state "left exhaust pistons
go in cylinders 1-4-5-8" and "right exhaust pistons go in cylinders 2-3-6-7".
.
Does anyone know what is the correct piston orientation and corresponding cylinder for the KB Hypereutectic pistons ?

PS I am uploading pics of the pistons

[pippintook]

This is a KB133 "left exhaust piston".

[pippintook]

This is a KB133 'right exhaust piston'

[pippintook]

KB133 , 4 left exhaust pistons

[pippintook]

KB 133, 4 right exhaust pistons

[Jeff Walker]

Just putting a 400 together for a customer using the same pistons. Here is how they are installed. Don't to forget to gap your upper ring the recommended amount aslo. I set this one up at .031-.032 gap.

[Malky]

Isn't it pretty obvious? The larger valve cutouts are for the 2.11" intake. The smaller cutout is for the smaller exhaust valve. This has to match the side of the rod chamfered for the rod journal fillet radius. At least, it was obvious to me but the shop that installed my pistons assumed it was for a Chevy and got it wrong.

[pippintook]

Thanks for the help. I too, assumed the larger cutout would be for the 2.11" intake and the smaller cutout would be for the smaller exhaust valve. But, I like to doublecheck these things and make sure before making an assembly mistake. The top ring was gapped at .032.

[Malky]

MFC, I reread my post and it came across as a bit snappy. Didn't mean it that way.
I installed KB hypereutectics on my 455. They came with dire warnings about ring gaps. Did you see that in the instructions?

[pippintook]

Yes, I saw that Malky. Thanks. I have gapped the top rings accordingly at .032.