VT Cams installed... my opinions

[98SteedaStang]

So you went with the 270 grind? New springs too right? The VT are a more aggressive spring? I was debating between comp 270's and VT stage II's. I need to look up the numbers on both to better compare them.

 

[nickthegenius]

I read the following quote:

Comp make 3 stages of cams for the PI 4.6 right? What stage do you have?

as "Comp makes Stage 3 cams for the 4.6....blah blah blah"

So due to my temporary dyslexia, I responded to the use of the XE278AHs which everyone that I have read about on the boards that tried them have had p/v clearance problems with them due not so much because of the lift, but because of how long the are open with the long duration.

XE270AHs have had problems in quite a few engines also. Starkie and AutomaticWeapon both lost engines for various reasons and then found out when the pulled the engines apart that there was a clearance problem and didn't know about it.

I have the XE270AHs and am now interested in geting a borescope (sp?) to check out my own engine. I'm happy with the power I'm getting, but I want to make sure that there isn't an issue that I'm going to pay for later.

 

[ProCharger GT]

some of you may have read my post about the crower cams.. turned out to be a bad grind on the cam; i have no PTV contact at all with a .612 lift and the crower springs/titanium retainers. what is the spec's on the XE270AH?

 

[GinoGT]

I believe the problem with the PTV contact with some SHM cams are because they grind their cams 5 degrees advanced. Sounds pretty stupid to me.

 

[98SteedaStang]

I just wonder if I'll run into problem because of the headswap, I know I have very little PTV clearance now after the swap. You guys know anything about that?

 

[nickthegenius]

I just wonder if I'll run into problem because of the headswap, I know I have very little PTV clearance now after the swap. You guys know anything about that?

If you have a stock shortblock with flat-tops and will be running Comps PI style cams, you'll be SOL. The guys that are having problems have dished pistons so with flat-tops you'll have even less clearance. So you will either stick with one of the NPI grinds that Comp has or call them and see what they recommend.

what is the spec's on the XE270AH?

Advertised duration 270/274
Duration @ .050 234/238
Lift .550/.550
LSA 113*

The problem with them isn't with the lift, but the combination of the longer duration and Comp Cams inclusion of a 5* advance ground into the cams. From what I read, this makes them a bit snappier off the line so it makes the gains feel even greater on the old butt-dyno but on a real dyno there isn't going to be much difference in peak hp between a cam with no advance and one with the 5* advance, but there might be a small shift in the powerband.