What can i expect???

[JTraik]

I just bought a shaft rocker system and a #10 series cam kit for my '68 472. I heard that their will be noticible power gain, but how much exactly are we talking here?

Due to my ignorance with cams i would like to know what this means... I took the caliper to my old camshaft where the lobes were visibly worn down in some areas. I took some of the best looking lobes and compared it to my new cam. I found that even worn down, my old cam lobes were slightly thicker from tip to end, compared to new cam. And also the thickness, side to side, of my old cam also had a greater value than my new cam. So basically my old cam is bigger all the way around.

Can someone explain to me how that produces more power? I can see how it might be a "quicker" cam but i do not understand the rest given my measurements. My old cam is most definitley stock to the engine. Thanks.

[51iron]

the lobe on your new cam is ground inside of the old lobe, which means the heel is ground off but not the top. you get more lift and duration with a smaller lobe. It also requires a longer push rod to work.

[STDog]

I just bought a shaft rocker system and a #10 series cam kit for my '68 472. I heard that their will be noticible power gain, but how much exactly are we talking here?

new core ground to #10 or a regrind?

Due to my ignorance with cams i would like to know what this means... I took the caliper to my old camshaft where the lobes were visibly worn down in some areas. I took some of the best looking lobes and compared it to my new cam. I found that even worn down, my old cam lobes were slightly thicker from tip to end, compared to new cam. And also the thickness, side to side, of my old cam also had a greater value than my new cam. So basically my old cam is bigger all the way around.

You should check the web for a camshaft primer. Some place like HowStuffWorks (http://auto.howstuffworks.com/camshaft.htm) or a hot rod magazine.

Lift is the difference in the radus at the base circle and the top of the lobe. So you have to compare that. Given that the measurement you dmade is smaller, I'me guessing a reground cam. You should have new pushrod for it that are longer than stock.

but looking.
#10 specs:
270-285 / Duration @ .050 Range: 220-228 / Valve Lift Range: .525"- .538

If you compatre to the specs for the #5 (which has a little more lift and a little more duratuons than the '68 stock cam)
358-266 / Duration @ .050 Range: 208-215/ Valve Lift Range: .495"- .510"
And the rocker arm ratio stock is 1.62:1.

So the stock lift was about .495, but on the cam that's .495/1.62 = 0.305
The #10 is .525 at the valve, so at the came it's .324.
So the difference in lift, at the cam is only 0.019". that 19 thousandths (1/1000) of an inch :!:
Also important is the duration are 0.050 lift, wich is 220 cersus 208, so an extra 12 degrees the that the valve is open.

Problem is it hard to see that difference. You really have to mesure it with a degree wheel and a dial indicator. And comparing a regrind to a non-regrind just cannot be done visually by most.

Can someone explain to me how that produces more power? I can see how it might be a "quicker" cam but i do not understand the rest given my measurements.

Again, you should check the web for a camshaft primer. Some place like HowStuffWorks (http://auto.howstuffworks.com/camshaft.htm) or a hot rod magazine.

[JTraik]

new core ground to #10 or a regrind?



It is a new cam from comp. I have the kit for it which includes longer pushrods and stiffer springs. I got the shaft rocker system because looking at the stock setup makes me so nervous.

[Nashalac]

I'm not positive but I think the shaft rocker system has higher ratio rockers than stock which would lift the valves more.

[Ted in Olympia WA]

Depends on the rocker system if it higher lift or not.

If you purchased the cam from MTS it should have came with the cam carb that would tell you if it a Comp cam or not?

TED

[JTraik]

Yeah heres what it is... the shaft rocker system comes with custom pushrods that are apparently shorter than my original ones. The ratio is also different. As far as the cam goes it is definitley a comp cam, i have their factory receipt.

So does anyone know what kind of a power gain im going to be experiencing from this cam upgrade? Thanks.

[Al from MTS]

FWIW all Cadillac performance cams are ground on a reduced base circle. The only new cam cores built for our engines, are designed for stock use.
As you increase lift you need to grind the cam with a reduced base circle. So in the case of the Cad, whether or not the cam core is new, is not why it has the reduced base circle. It's a factor of how much lift you are trying to produce.
Our budget shaft rocker system #VT42 does use shorter than stock pushrods. The rockers are shipped with instructions on how to set them up.

We sell way more replacement pushrods than I would like. Tells me that no one reads any of the instructions we send. Mabey it's just a guy thing.
1.Open box - toss instructions
2. bolt on parts
3. Fire her up and bust stuff
4. Call MTS and ask all the questions that were answered in instructions you tossed out.
5. Spend more money and order replacement parts.


The VT42 rockers are made with their mount blocks too short on purpose. It's easier for the installer to raise the rockers to get proper preload than to lower them. Lowering would require machine work to the mount pedastals. They are shipped with two different thickness washers so you can adjust preload. This will work for most stock or reduced base circle cams.
Another point mentioned is different ratios of aftermarket rockers. It's one reason why I grind several versions of our cams. We grind more lift into cams sold to folks using lower ratio rockers to regain lift.
That's why if you buy a cam from us, I always ask what rockers you are using. You must also be careful not to over lift your valve springs as well.
Example is our MT15 works with VT42 rockers and our S/S spring kit. If you use the VT49 rockers in this mix, you can over lift the spring kit and bust the springs. The higher ratio rockers and the MT15 cam would need to use our S/S/C spring kit.
Our # 10 cam in your engine should pick up another 35-40hp. You will notice a big difference in mid range and top end power over your stock cam.