Topic: which stock cam should i run

[NH Mowster]

Here is 2 cams, the one on the left came out of a 40 cid engine and the one right came out of a 42 cid engine. Now the one on the right measures .280 lift but the one on the left seems the same but it has a casting line so it makes it hard to measure. The cam on the left (40) has a slope at the bottom of the lobe and the lobe is rounded at the top. The one on the right has a sharp milled angle at the bottom of the lobe and the lobe has more of a flat spot on top. I watched Don's Opposed twin DVD and he can tell which one to run just by looking at it so I hope someone here can do the same.

[cycloneracer]

Throw them in a bag and pick one.

Stock cams are the same.  All junk on a racer. 

Buy a performance cam.  You will be happy!!!!

[NH Mowster]

I would but I'm running all stock parts in this engine and putting all the good stuff in my pressure lube. This is to get me started for the beginning of the race season next year till I can get all my parts together for the pressure lube then its going in my racer and the sticker will be my back up engine or my buddy might run it.... if he ever starts on his mower soon! The $350 billet flywheel that's mandatory by our clubs insurance for next year kinda drained me on extra cash for goodies till tax time. Just building a good stock performer till the real engine gets done 

[cycloneracer]

So grab the cam that makes you feel good.   


Get some seat time then mod your engine when you get the cash. 


Seat time is the best performance part you CANT buy!!!!

[birdman_express]

Seat time is the best performance part you CANT buy!!!!

Second that one!!!

[Rooster]

Run the one on the left, it has more duration.

[NH Mowster]

OK thanks Rooster 

[garrywarber]

Run the one on the left, it has more duration.

Could you expand on that?  Is that what I should run for the best low (3500-4000) RPM torque?  How about the 46 camshaft?  What is unique on that, if anything?  In my 46 would the 46 cam be best for what I want?  Common sense, if I had some, would say the 46 cam would be best with the 46 crankshaft because my RPM is right in the factory design range, but it seems briggs is spooky-weird on that stuff sometimes...  Or I am, I'm kinda confused...
Garry

[NH Mowster]

Could you expand on that?  Is that what I should run for the best low (3500-4000) RPM torque?  How about the 46 camshaft?  What is unique on that, if anything?  In my 46 would the 46 cam be best for what I want?  Common sense, if I had some, would say the 46 cam would be best with the 46 crankshaft because my RPM is right in the factory design range, but it seems briggs is spooky-weird on that stuff sometimes...  Or I am, I'm kinda confused...
Garry

that's kind of a tongue twister  I think the stock cam would be good for that range since that's what the factory base there performance of the engine on that RPM. I know that my stock cam stops performing around 4500 rpm and since my splash will have mostly stock parts in it I'm only going to turn it 4500-4800 because 4000 rpms got me around our track pretty good this year and I could pass ungoverned oppys that was turn somewhere near 4500-5000. Its all in the gearing. If you don't plan on turning a stock motor past 4800 then I think the stock can will do just fine given your engine is in good mechanical shape and some oil mods have been done. Hope this helps in some way 

[willenglish]

You guys need to buy you an inexpensive degree wheel....and a dial indicater..they can be bought inexpensivley too. Then you can check those cams you have there...and later when you get better stuff to race with...you can learn about your race cam too. The two you have there...Id be surprised if you see much differance in either one....lift,duration, or base circle. If you plan on being in racing...these are indespensable....and you need a good timing light to set your timing with too. Its not that big of an investment.

[George Herrin]

A stock cam is a stock cam, the chances of you truly feeling a difference are slim to none.

[Rooster]

A stock cam is a stock cam, the chances of you truly feeling a difference are slim to none.

true...but he asked which one of those two to use, the one on the left has a bit more duration which does aid slightly in cylinder filling...very slightly, but if you have a choice to make.....

[Burton for Certain]

Weld it up, stick it in a vise, then go to town with a grinder. I know a guy who did that and ran nationally this year. Won a race or two also.

[BIG AL 202]

RUN THE ONE THAT LETS YOU RUN THE OIL PUMP, YOU SAID IT'S A PRESSURE LUBE. 40'S DIDN'T COME AS A PRESSURE LUBE.

[Jim Knutson]

model 400700-400799 types 1201,1203,1219......pressure lube