Cam specs for Ported Heads

[XfireZ51]

As I have followed Todd's exploits with his 427 and interesting cam profile,
it occurred to ask whether the stock cam profile is optimum for the additional airflow available through ported top end and heads? Not sure how much more airflow a set of GVD heads provides, but it would seem logical that using stock cams doesn't exploit potential of the added airflow. Is it a matter of degreeing the cams differently or require a cam regrind to add more lift and/or duration?

[flyin ryan]

Originally Posted by XfireZ51

As I have followed Todd's exploits with his 427 and interesting cam profile,
it occurred to ask whether the stock cam profile is optimum for the additional airflow available through ported top end and heads? Not sure how much more airflow a set of GVD heads provides, but it would seem logical that using stock cams doesn't exploit potential of the added airflow. Is it a matter of degreeing the cams differently or require a cam regrind to add more lift and/or duration?

'Optimum?' Um'....That'd be a no. Also, can't just simply degree the cams to do what you need them to do, in this instance. Never a bad thing to degree & will/may help a bit, but that's it.

[XfireZ51]

Originally Posted by flyin ryan

'Optimum?' Um'....That'd be a no. Also, can't just simply degree the cams to do what you need them to do, in this instance. Never a bad thing to degree & will/may help a bit, but that's it.

FR,

That's why I asked. Here you have all this additional air and ....

[flyin ryan]

Yup...You got er', that's the deal in a nutshell

[scholtmj]

I'm curious too. Given a set of heads ported to "today's" standards, what cams would work best with ported heads on a 350, 368...so on. Drivability/intended use aside.

Sounds like the "while I'm there" bug has hit. Xfire just spent lots of $$ on ported heads and doesn't want to put stock cams back in! I'm in the same spot.

[XfireZ51]

Originally Posted by scholtmj

I'm curious too. Given a set of heads ported to "today's" standards, what cams would work best with ported heads on a 350, 368...so on. Drivability/intended use aside.

Sounds like the "while I'm there" bug has hit. Xfire just spent lots of $$ on ported heads and doesn't want to put stock cams back in! I'm in the same spot.

When I re-did my Xfire I read up on cam selection including some of Vizard's work. Seems obvious that the stock cams, altho working well, don't take full advantage of the additional airflow. If you're going to do the job, try to maximize the power output. On an SBC, it's easy enough to play with cams.
The LT5, not so much. If Marc H. is lurking maybe he could chime
in.

[Pete]

I will put it this way.
On a stock motor the stock cams are underpowered by the heads/intake.
After porting, stock cams are the weak link/underpowered.

We know when you port the heads/intake we pick up 30-40hp .

That tells me after porting we have reached stock cams potential,since after we add bigger cams we pick up another 25-30hp which means we have not reached the heads potential.

I hope i said that right.
Pete

PS
I would also like to know the best cam specs.
I know we could get 500rwhp from a 350ci the question is how much driveability will we have to give up.
If ported LT5 heads have 255cc intake port and 340cfm what would be the right cam for max power anybody have a cam/head caculator.
I would like to try a bigger intake cams maybe in the future when money starts to grow on trees,it gets a bit pricey, unless i find a low priced SGC Stage III intakes or maybe borow a set.
Man i would love to get another 15-20hp and hit 130+mph :-)




.

[flyin ryan]

Originally Posted by Pete

I hope i said that right.
Pete

PS
I would also like to know the best cam specs.



.

Said just fine Pete . This is a trap guys fall into, looking for the 'Perfect' cam(s)..., doesn't exsist. Take that cam/head calculator or whatever they're called & throw it in the bush. I never used one, never have & never will. Way, WAY too many variables to compute. Trial & error, that's the game, suck's major big time with an LT-5 though, no doubt about that. When I'm looking at/for a cam profile I'll have my guys grind, I take all the info I have but at the end of the day, honestly, it ends up being instict. Always remember to error on the small side, if on the fence. Most guys on here should follow Pete's lead, if you ask me. For his combo, his car works dang good!....That's not small talk.

[XfireZ51]

I'm not one to discount school of hard knocks approach. Especially knowing Pete personally, I respect his knowledge and hard work. On the other hand, there's physics involved, not black magic. That allows modeling and simulation especially with the computing power now available. At the very least, I would be interested in seeing what the calcs say. Secondly, it would be of interest to compare the theoretical with the empirical.

[LGAFF]

Originally Posted by XfireZ51

there's physics involved, not black magic.

Actually I walked in on Pete once in his garage while he was in the middle of sacrificing three chickens and a goat....the next day he ran 129mph.

So maybe alittle black magic involved.