S3 cams in an S4? pros and cons

I have come across some S3 cams for a good buy.

what is the differance between them and the S4 cams?

If we agree that S3 cams came from 85-86 US 928s, then I know something... They are a better grind then the S4 cams, closer to GT cams in grind. However to fit an S4 a special modification needs to be made to a bearing surface (as I recall). I could dig up more about these if needed.

They would be a more hp grind particular at higher rpm if I recall correctly.

Stan I think I read some of your post on this while your heads were at the shop.

So is it just 1 cam that needs to be fit to the head?
and
are any mods required to the head?

928mac;6967 wrote: Stan I think I read some of your post on this while your heads were at the shop.

So is it just 1 cam that needs to be fit to the head?
and
are any mods required to the head?

My recollection is that just 1 cam needs to be modified, no mods. to the heads.

I had heads line bored because the cam caps that went with them were lost. The cams I am using started life as S4 cams but were redone with a race specific grind.

did you miss type Stan? shouldnt it read 85-86?

if so then yes Id agree that these would be S3 cams similar to the GT cam grind.

Brad....if you have the Moorehouse CD set you can read the cam specs in the tech books.

malcolm;6970 wrote: did you miss type Stan? shouldnt it read 85-86?

if so then yes Id agree that these would be S3 cams similar to the GT cam grind.

Brad....if you have the Moorehouse CD set you can read the cam specs in the tech books.

Yes, I have now corrected the dates.