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Xe278ah cams install issues?

10580 Views 19 Replies 9 Participants Last post by  jaylop1986
Down the road I want to put in some cams. I like to have an idea and plan of everything I'm gunna do so I had a couple of questions..

I was looking at the XE278AH Cams. Nice Rough Idle. But will they clear stock pistons (without major mods like flycutting or cam timing)? Are the XE270AH better..?(a little more mild)

How about these comp cams vs. Hitech Stage II Cams... Which are better?

Any and all help is appreciated. Take care.

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couldn't tell you honestly but damn, it seems like you have a lot on your plate. the full saleen body kit, two tone paint, and now cams?
haha yea i plan ahead. ALOT but it will all happen in that order. Provided I don't come across some bangin deal on some cams. I was asking bc i found some NEW XE278AH cams on CL for 350$. Thats a good price.
I would go with Hi Tech or custom cams would be the best. the 278's are good but i like Hi Tech better.
278's require flycutting the pistons. 270's are close.

Go with HiTech or CMS Stage 2's. Both have outperformed the 270's without flycutting on a consistant basis.
How do those compare with Trick Flow's TFS-51802001? 264/264, .550/.550
What is most Duration/Lift you can get on stock 4.6L without doing mods to clear pistions?
It's a combination of centerline and duration that's the problem, not the lift.

The 270's and CMS stage 2 cams are borderline safe, and must be degreed in, or you're taking the chance of PTV contact. Some that have been degreed in have had less than .005 PTV clearance, which is crazy.
It's a combination of centerline and duration that's the problem, not the lift.

The 270's and CMS stage 2 cams are borderline safe, and must be degreed in, or you're taking the chance of PTV contact. Some that have been degreed in have had less than .005 PTV clearance, which is crazy.
.005 clearance is more than crazy, thats asking to destroy your engine. They are measuring this when it is cold, not @ running temps and besides metal expanding when heated it also stretches @ higher rpm's, you might think that the rods stay the same length when the engine is running but you would be wrong!!!! They stretch and contract, think of the loads it under. To move that piston @ 6000 rpm's that piston and rod must go up and down in less than .01 second. Just the force of stopping the pistons movement must be tremendous, now think about the force of the explosion (combustion) that propels the piston crank n rods up and down in under .01 seconds and this is complicated by the timing chain which even if new will stretch @ high rpm's and someone thought it a good idea to have less than a human hair's gap between the piston and the valve. When I used to build race engines or blue-printed an engine I would NEVER have less than .020 and that is on a race engine that will be worked on every few laps/ rounds/ races........

I will take ANY BETS that if this person EVER misses a shift or over revs the engine there WILL BE a MARK (@ the very least) on the piston where the valve hit it......... and wouldn't doubt it if the valve is bent.........
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Whats most aggressive cam I should use on the stock 4.6L. And exactly is process of the mods you make to pistion/valve when needed. At school I have a valve machine, not sure what it does exactly havent gotten to use it. May be able to do something with that not sure.
HiTech Stage 2's or MHS Stage 2's are probably about as safe as they get while still being fairly aggressive.

Just remember, an aggressive cam on the street is not really a whole lot of fun when cruising in traffic. I know everyone wants the noise, but trust me, it's not worth going too big and not enjoying driving it everyday.

To notch the pistons requires you to take the heads off, put clay over the top, mark where contact is made, and then take a notching tool and cut into the pistons to make room. I'm not doing all that, I ordered new aftermarket intake valves to use with my VT Stage 2's. They have a thinner profile than the huge stock valve, and will give me the clearance I need to run these cams safely.:bigthumbsup
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It would be great if someone started a cam sticky because I believe that that would produce alot of good information for people. I am looking to do cams in the future and I have had questions and will continue to have questions, so a sticky would be a great tool.
Hitech stage 2 all the way, they are the best performing cam with stock heads. my 01 put down 300rwhp with them and basic bolt on.

my sons 98 put down 298rwhp 315 tq with them and a pi heads through stock exhaust and stock air intake....

Hitech cams sound great and perform awesome.
I would have to agree with John, the HiTechs seem to perform the best on stock heads. Once you get ported heads or TFS heads, there's better options, but definately the best for stock heads.

I know of 4 people personally who are making right at 300rwhp with stock heads and HiTech Stage 2 cams.
Yep, those are it......

Here's a clip from Youtube of them.

And here's the VT/CMS Stage 2's that I have. But I recommend them only with piston reliefs or aftermarket intake valves.
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Where do you get aftermarket intake valves? Can't seem to find them, only springs,rockers,cams and such. About how much does it cost to cut pistons to get more aggressive cams
modularheadshop has them, they're $249 for the valves, and then figure about $600-800 in labor to have the heads removed, reconditioned and reinstalled.

To be honest with you, the performance difference between the VT and Hitech cams on stock heads sways towards the Hitechs. I would go with them for the simple fact that I can bolt them in, set the timing and make 300rwhp with all the other bolt ons.
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I have full access to reg shop equipment at school and all the knowledge of the instructor not to let me screw anything up. These instructors are great, both are actually building "race" type cars of their own on THEIR own budget and wont let me screw anything up. So labor wont be issue.
I got my pistons cut from modular head shop(great guys to do deal with) i cant throw the price i got em done for out there... But i can tell u it was super cheap call them and talk to them maybe theyll work you a good deal to
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