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Confusion on XPZ Head Combonation

pontiackid

pontiackid

New member
Alright. Got an XPZ, will be running YellaTerra 1.6 Rockers and not sure on the Springs. Must I run the equivalent of ZZP's Stasge 3 Heads and have additional custom work done to them or could I get away with a CNC'd Head?

Looking on Zippy's (ZZP) XPZ webpage

Modified heads are required with 130 pound springs.
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and this a paragraph below...

Highly recommended supporting mods for this cam would be:
Rollmaster double timing chain, Comp OE-R lifters, 105# valve springs, & retainers.
Click to expand...

I have some 105's from my XP Build that are in great condition though should I be upgrading to the 130's while I'm at it (old build was an XP/105...)
 


the XPZ can technically be run on stock heads, but wont make any power because it wont be able to flow like the cam needs.

but yes, i would run 130# springs with ported heads.
 
the XPZ can technically be run on stock heads, but wont make any power because it wont be able to flow like the cam needs.

but yes, i would run 130# springs with ported heads.
Click to expand...

Very true. But you have to give the vavle guides the much needed clearnce they need, then you can run the xpz on stock heads. Which would be about as dumb as a no legged man at an ass kicking contest. I'm sure you already know this. Just wanted to make sure some one doesnt get a great idea and try it out not knowing that.

I'm running custom heads with over sized vavles,130 pound comp cam springs,Low Mile Stock L36 lifter's, and a double roller timing chain with no issues at all.

The head work, springs and doube roller is all a must. If you dont have some decent heads then I wouldnt waste your time with an xpz. Save your self the work of pulling the heads at that point and just run an xp cam.
 
Boomer1919 said:
Save your self the work of pulling the heads at that point and just run an xp cam.
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Don't worry this is a new motor build aswell... (look at sig) So in order to run the XPZ and 130's at a stock RR ratio the heads (wehter ported thrasher, s1, s2 or s3, ect need to have the valve guides shortened or milled?

Bio248 said:
the XPZ can technically be run on stock heads, but wont make any power because it wont be able to flow like the cam needs.

but yes, i would run 130# springs with ported heads.
Click to expand...

Thanks, Bio... I'm just trying to figure out wether I need to have an additional work done with the heads in order to "be safe."

And Nick... well Brian's build is contagious
 
everyones build is contagious. i was about 2 weeks from a big build too until my tranny went.

do you already have the XPZ? if you dont i would consider changing cams.
 


Don't worry this is a new motor build aswell... (look at sig) So in order to run the XPZ and 130's at a stock RR ratio the heads (wehter ported thrasher, s1, s2 or s3, ect need to have the valve guides shortened or milled
Click to expand...

Yes, they must be milled. I forgot how much they need milled. I wanna say stock guides need milled .30 to clear. But dont quote me on that because I dont recall what it is any more off the top of my head.

everyones build is contagious. i was about 2 weeks from a big build too until my tranny went.

do you already have the XPZ? if you dont i would consider changing cams.
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I strongly disagree.. I've ran 3 different set-up's and working on my 4th build as we speak. IMO if anyone is going to go cam, and they dont mind spending a little extra money then go with an XPZ.. XPZ is flat out nut's for any M90 car. I'm sure you can get some custom grind and be making some great number's. But for somthing you can buy off a shelf with out having to flow-bench your heads and so on for a custom grind, the xpz can't be beat. It's a little money up front, but the pay off is great with the new found top end that these car's lack.
 
i am not so concerned about making power, but the XPZ is such a little, weird cam. i would much rather run an IS3 and put some lsx guys to shame with the stupid idle. i would also consider running a TEP again cause its just straight mean.

although, if i were to do another build (which is in no way shape or form happening) i would go with a cam similar to a NIC except bigger because i dont do intercoolers.
 
XPZ is tiny compared to my TEP CAM :D
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It's true it is.. But the thrasher cam is a bit overkill for any m90 car imo. I'd want a m112,mp112, whipple ect for that cam. Then it'd be the cat's ass. The size of the cam doesnt mean much to me, What matter's most is how well it's going to perform for me and ease of tune.

i am not so concerned about making power, but the XPZ is such a little, weird cam. i would much rather run an IS3 and put some lsx guys to shame with the stupid idle. i would also consider running a TEP again cause its just straight mean
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If power isnt your thing and you want flat out nasty idle. Then I agree, I just find it hard to spend a decent amount of money just to have the ruff idle. You can make anything cam hard with just a little bit of tune work. But to each there own. Again. I belive the IS3 cam would work well with somthing bigger then an M90.. I know of some mp112's that have ran rather well with the cam.

Boomer
 
i know an XPZ is a good cam to go fast with, but i never intended to go any faster than mid 12s with my car and if i couldnt do that with an IS3, TEP, or NIC then i dont know what is wrong with my car.
 


I already have the XPZ... I personally Blame 99blackgt (Brett) for finilizing my decision on the cam...

Bio, you had mentioned that the XPZ works on a stock head but, do to the head it wouldn't flow like its supose to. The heads will be ported and top notch which ever way I'll go but, your comment really seemed to stick a bit. Why? IDK? :th_scratchhead:

But is the valve size, what would primarly be holding the XPZ back on a Stage1 head? Seems according to the power list that all the guys running the XPZ are running ZZP's Stage 3 Hand Proted Heads with #130's.
 
what heads to you have? i would keep stock valves and run l32 heads (bigger stock valves to begin with) if i were to do it again.
 
you can honestly get a way better set of heads than ZZP even sells for about $800 worth of porting and polishing (and cleaning and rebuilding) at a local motor building shop. they have seen our heads before due to the old buick 231 (GN, t-type). its your best bet and thats what i would do if i were you.
 
Yeah but I've heard the 231 GN heads are WAY different than ours...that's the reason I strayed from a guy around here to do my heads.
 


well, come on. heads are heads for the most part. you cant just blindly run in there with a dremel and expect it to be better. most engine shops know what they are doing regardless of the parts they are working on.
 
Bio248 said:
i am not so concerned about making power, but the XPZ is such a little, weird cam. i would much rather run an IS3 and put some lsx guys to shame with the stupid idle.... i dont do intercoolers.
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LOL I love it, nice comment.

I truly love my IS3 cam in my car, and I dont do intercoolers either. Bio, your a great guy. :th_thumbsup-wink:

~F~
 
yeah, the longer my prix sits in the yard the longer i think about putting money into it and making it run well with a nice setup like i had (never installed) before my demod, but i dont have the room nor money.
 
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