79corvette

I want to swap out my old stock cam for a new one. I found summit selling some of there own brand, and they are really cheap and come with the lifters. I was looking at a cam and it's numbers are duration at .050" intake: 214 exhaust: 224 Lift: I: .442 E: .465 Lobe seperation 112 . Is this a good camshaft? What type of numbers should I be looking for. I want to have around 350HP and more torque. I also have the vortec heads so I cannot have more than .465in of lift at the very most. My rear end a 4.11 or higher gear. Thanks for the help. My setup is in my sig.

bence13_33

Stock L48 cam specs are:

Intake: 195 Duration @ .050" , Lift .390"
Exhaust: 202 Duration @ .050" , Lift .410"
Lobe Seperation 112

Since you have 4.11 gears they will help your bottom end. The Vortech heads stop flowing around .500" lift. So there is no need to go with any more lift than .500". The cam you have selected is pretty close to the same cam I ran in my L48. It should work well with your setup, and you should notice a pretty nice increase in horsepower.

In all actuality you should change the valve springs whenever you switch cams...especially considering the cam you have selected is the absolute most your current valve springs can handle. Just my .02 .

79corvette

I bought the heads new in May, so I think the valve springs are still good.

bence13_33

You might be ok, but is it really worth risking a busted valve spring because you didn't want to spend money on a new set of springs?

The problem is that to a certain extent valve springs have a "memory." That is to say that once you run them for a while with a certain camshaft they get used to being compressed to a certain point and no further. By switching cams (to a cam with a larger lift) you are compressing the valve springs more. This is especially a concern in your case because your valve springs are only good up to a .465" lift....the exhaust side of your cam will be pushing the valves open to .465".

It's kind of a hit and miss deal. You may be ok, you may not be. If it were me I'd get a new set of valve springs. Also, I'm not sure how that cam will work with your current converter...is the converter stock or a higher stall. My guess would be with your 4.11 gears you should be fine.

Just out of curiousity have you considered going with a solid flat tappet camshaft? A solid flat tappet setup will cost roughly the same amount as a hydraulic setup....and produce more horsepower.


[Modified by bence13_33, 8:25 PM 9/22/2003]

79corvette

I was looking around today, and foudn some new springs for that will fit and good for .490in of lift, I will get those if I get that camshaft. I did not know that the springs have a "memory", that is good to know. And no, that type of damage is not worth it because I didnt' get new springs.
Yes my converter is stock as far as I know.
What is solid flat tappet setup? Do they require more adjusting than the hydraulic ones? The cam that I was looking at is only $80 with lifters, so if it is around the same price and more HP, I'd go that route.

bence13_33

$80.00 is pretty cheap for a camshaft and lifters. I don't remember how much I spent on my cam, lifters and valve train but it was a lot more than $80.00 (I went with all Comp Cams).

I would stick with the $80.00 cam and lifter kit and a replacement set of valve springs and you are in business.

A solid cam is nice because they are capable of higher RPMs and do make a little more horsepower than a comparable hydraulic flat tappet. Yes, solid flat tappets do require adjusting the valves every so often...but really people blow this out of proportion because it does not need to be done that often and it doesn't take very long.

Good luck with everything, I'm sure you will be happy with the results. The cam should work well on the street and at the strip with your setup.

Matt Gruber

get a POWERHOUSE catalog.
they have a big selection of cheap SOLID cams.You can wind to 7000
:cool:
about $49 cam $45 lifters

Fevre

I bought a Summit cam just a step below that one (.424/.444 204/214, great torque and fun till about 5000 then it laid down. Really was a great street cam for cruising and lighting the tires up. I am thinking of the cam you list for a 383 tpi truck application I hope to talk my father into, should be even more of torq monster.

TTop Tony

Thats the same cam specs of the cam that Jasper puts in there crate motors. My engine has plenty of low end grunt but dies at around 5200rpm. Jasper rates there engines at 300hp with stock heads and headers so with vortec heads I'd guess 330hp. Thats just a guess though.

Imothph

Sounds like a nice Cam. With a 12 degree LSA on that cam you may not notice much of a lope, if any and assuming your looking for one in the first place. As to Valve springs. I have ran two Comp Cams Magnum 270H cams in my 76 Camaro and in my 57 Chevy, both with stock valve springs. I spoke to the Comp cams tech people on both occasions and the consensus was that the stock springs will be just fine with the lift the 270H has ( 470, both intake and exhaust) Replacing the springs for you cam is probably also unnecessary since its lift is lower and unless your planning frequent WOT 1/4 mile runs then the stock springs should be fine. As an example, I ran my 76 Camaro ( 350 HP w/ 270H Magnum - 470 lift, 10 degree LSA and nice lope) back and forth on the free way, 60 miles per day two and from work for two years- never an issue. I do reccomend long slot rockers and if you can, go with roller tips.

79corvette

Since I am getting new valve springs that can handle more lift, how would a cam with .465/.465 lift, duration 224 224 and lobe seperation of 114 be? Will there be much of an increase in power over the other cam? How can you tell what effects cam performance, such as the duration and lift for HP and torque, obviousily more lift more flow, but I don't know about duration.
Does anyone have a link to Powerhouse, I wasn't able to find one. Thanks for all the help so far.

bence13_33

What's this motors intended use?

The cam you currently have selected will pull to about 5200RPM or so. As for the LSA...I would go with a 110. Personally I'm a big fan of single pattern cams such as a .465"/.465" cam. There really is no need to go with a split duration cam unless you are compensating for poor cylinder head flow numbers or a poor exhaust system (in this case....get a new exhaust system). You may be able to go with a little more cam but I don't know for sure....I really don't know how your stock converter will react.

If it were me...I'd shoot for maybe a cam that is a step larger than the .465" lift cam....but that's just me.

Smokehouse69

There are so many variables to consider when you are shopping for a cam, spending a little more money up front is a lot better than a small amount that leaves you unsatisfied.
First of all you need to figure what your compression is with the 62cc Vortec heads. I am assuming that your L-48 still has the stock pistons, I figure compression is about 9.8-1, which is pretty close to the limit for pump gas and cast iron heads. So you don't necessarily want a cam that has a narrow LSA or long duration, because they both affect your dynamic compression. I'd wait and get some input from some real professionals before you order a cam just because it is cheap.
Another thing to think about is that your Vortec springs (if they are stock regular Vortec heads and springs) won't handle lift much over .470. As far as I know there are very few people who make springs that are much better than the stock ones for a stock Vortec head. It is an element of the design of the valve spring pockets and valve guide height. The spring pockets can be widened and the valve guide stems milled down, but unless you plan on using a high lift cam it probably isn't worth it.
There are a number of guys on this forum who can give you some great advice on which cam will give you the best performance and driveability with your engine. GKULL, Ganey, Tom454 just to name a few. Wait and see if one of those guys will chime in with a recommendation.