Camshaft??

[Alan Roehrich]

You don't need roller cam bearings. I wouldn't run a 50MM cam in a big block.

Note, I've edited this post for clarity:

I meant to come back and clarify this, as I answered it "on the fly" or "off the cuff".

Stock core diameter is adequate for most applications. Comp calls that a 1.948" core, and does not give a "MM" dimension, however some research and conversion to metric dimensions yields 49.47MM as the dimension for a stock diameter babbit bearing 1.948" core.

A 50MM (actually 49.98) core is actually 1.968", which most cam companies list as a "stock diameter" for use with roller bearings. That is where the confusion here comes from. From what I've seen, the industry standard for core sizes refers to the actual stock diameter big block Chevy core as 1.948", and the "stock core diameter for roller cam bearings" as 1.968, or 50MM.

I'm actually surprised one of my friends didn't send me an email or a private message and bust my chops on it.

I certainly should have been more clear, and more careful. I hope this resolves any confusion here.

[MEXJOE]

Originally Posted by alan roehrich

you don't need roller cam bearings. I wouldn't run a 50mm cam in a big block.

please elaborate.

[Alan Roehrich]

If I were going to run a big core cam in a big block Chevy, I'd run a 54MM cam. You can do that on babbit bearings, for a "reasonable" cost. The next step would be a 55MM cam, also on babbit bearings, but the cost increases a good bit.

For the RPM range of a 396 that is not a 375 horse version, I think the stock size core is adequate for Stock Eliminator.

There are advantages to bigger cores, and to steel cores, not sure a relatively low horsepower 396 Stock Eliminator engine will really see them.

[Charles Rainey]

Quite often I see people giving advise on size of camshaft and what people should run. And Im sure that I will not get a response to this. Just how many of you people have run back to back studies of "larger camshaft" versus standard camshafts. When I say studies, I am referring to dyno tests or back to back track tests. I have very little thought to an opinion unless you have performed this your self.
charles

[69Cobra]

Originally Posted by Charles Rainey

Quite often I see people giving advise on size of camshaft and what people should run. And Im sure that I will not get a response to this. Just how many of you people have run back to back studies of "larger camshaft" versus standard camshafts. When I say studies, I am referring to dyno tests or back to back track tests. I have very little thought to an opinion unless you have performed this your self.
charles

It sounds to me like you are questioning Mr. Roehrich advice. I'm not a chevy guy but I still listen to what Mr. Roehrich's has to say. I would think he is basing his free advice on his personal R&D experiences that he spent lost of money to do. Just my .02

[Tom Meyer]

Stock core size on a big block is 50mm, 47 mm for a small block? Most big blocks go to 55mm when doing the roller bearing thing. Small blocks go to 50mm, the only thing i have seen with roller bearings is it turns over easy when setting the valves. Tom

[Charles Rainey]

Originally Posted by 69Cobra

It sounds to me like you are questioning Mr. Roehrich advice. I'm not a chevy guy but I still listen to what Mr. Roehrich's has to say. I would think he is basing his free advice on his personal R&D experiences that he spent lost of money to do. Just my .02

Mr Cobra.
No I was not speaking of Mr Roehrich or any one else in particular. But when we get into this type of specifics where it pertains to money having to be spent, I do like to know how they ascertained their opinion. Did they run test or is it from some one else opinion. I would like t see that info backed up by a firm statement of what it gained. Sometimes it is very easy to offer an opinion instead of a fact that they proved out themselves. I have worked in a dyno shop for years and have saw many theories tried. Some work, some failed. I have been away from it awhile, but I know how easy it is to offer advise instead of fact. If I am a person that has to spend the money, I really would like to know any quantitative data. Example, what did they try it on and just what were the gains. Many people spew out words but no data. Heck I had a shop teacher that had built some of the fastest cars in the world until I went too his shop one night. His lathe wouldnt even run fast much less his bicycle.
charles

[69Cobra]

Originally Posted by Charles Rainey

Mr Cobra.
No I was not speaking of Mr Roehrich or any one else in particular. But when we get into this type of specifics where it pertains to money having to be spent, I do like to know how they ascertained their opinion. Did they run test or is it from some one else opinion. I would like t see that info backed up by a firm statement of what it gained. Sometimes it is very easy to offer an opinion instead of a fact that they proved out themselves. I have worked in a dyno shop for years and have saw many theories tried. Some work, some failed. I have been away from it awhile, but I know how easy it is to offer advise instead of fact. If I am a person that has to spend the money, I really would like to know any quantitative data. Example, what did they try it on and just what were the gains. Many people spew out words but no data. Heck I had a shop teacher that had built some of the fastest cars in the world until I went too his shop one night. His lathe wouldnt even run fast much less his bicycle.
charles

I understand where you are coming from. It would be nice if the info was out there and people didn't mind sharing it. Just don't think that's going to be the case.