I did try searching for this info but what I saw was flat tappet related. If, it exists already, I apologize.


So, a newly purchased crate Chevy 350 Vortec makes 255hp @ 9.4/1 if memory serves. With new springs from Alex's, (.550 @ 130lbs) how much more power would a new cam make before the heads/compression became the limiting factor? More specific, what is the largest cam that can be run be before the returns became diminishing as far as drivability and low end loss of power? Lets call the top end an EPS with a 600cfm and headers through the back end.


- Rob
Also, 1/2 way through a deployment is a great feeling! Even if it is my 5th time across the big drink. 8 years to go!

Is that with or without head work to be able to use springs for a cam over about .460 lift?

Ah, great question! Alex's Parts has springs that fit, with shims included, that allow the .550 lift w/o head work. New retainers and locks come with the springs.


VALVE SPRING KIT, SB CHEVY VORTEC, HI-PERF HYD ROLLER - Alex's Parts Sales


- Rob

Are we talking about just a spring change here? Does this motor have a roller cam and lifters? If so, this type of change should just raise the rpm limits with in turn moves the motor up into a higher power band.

If you are just changing springs on a non-roller set up, be cautioned that you are increasing load on the flat tappet cam and lifters, which could lead to a cam/lifter failure.

Not sure which vortec cam you have but there was one that came in a ZZ4 motor that was a good cam .

LT4 Hot Cam and the L31 with the spring kit you mention, and 1.6 rockers, is supposed to be in the 400HP/400TQ range. Internet search "Hot Cam L31" and you should get a lot of study material. FYI, the L31 is rated at 255HP while running all accessories, and that's misleading when comparing it to other crate engine specs. If they rated like other GM Performance crate engines it would be more like 310-320HP with the stock cam (keeps your warranty good!). Look at the Ram Jet 350 for a comparison. That's the L31 with 1.6 rockers (no spring changes or other head mods), cam hotter than stock but not as hot as the Hot Cam, and it's rated at 351HP.

Thanks for your service!

Maybe Robert is talking about the service roller cam set up to run these springs and retainers, the 24502586 cam is 218/228° with .525 lift straight across. There us a GM service cam that comes with the entire set up under part # 12480002 .

I don't see where GM is posting any hp/tq numbers but I am sure its been flogged.

The other hot cam I am seeing is the 19244485 that's 234/242° with .539/.558 lift.
Again, I am sure one of the performance mags have tested these on engine dynos .

Robert, thank you for your service!

You are welcome and thank you for the kind words.
So, 400ish is the cap for a stock set of Vortecs at 9.4/1? That's pretty good all things considered. Probably has a flat torque curve to go with it! This was in an effort to find out what the largest duration cam, without regret of loosing low end torque and drivability, one could shove into this little guy and see good results. Pure curiosity. Thanks for the input friends!
- Rob

I have used these before and will probably again.

WOW! Wish they had been around when I did my Vortec. I stuck with a .450 lift cam. It makes prettty decent power, more torque than HP.