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Discussion Starter #1
Will i see any big gains by installing a set of ZZP CNC heads on Grand Prix GTP with :

ZZP Z7 Turbo kit
Intense S1X turbo cam or a ZZP ST1 turbo cam
3" ZZP catback
PI 2800 Stall

I know i'll be adding high flow fuel pump and 60# injectors and a lot more i'm sure.
But i just want to see if the CNC heads will hurt my low end torque. Or put it another way, will the heads hurt my performance at any RPM. I want the strongest power through out the whole power curve, not just peak.

I appreciate any help you guys can offer.
 

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I’m curious about this as well. I’m only running rockers, HV3 and power logs but my current heads are cracked between valves and need shaving so I’m leaning towards reman heads or CNC heads.
 

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Beware of reman heads. If you lean that way, I would highly recommend using a good machine shop. Over the years the times we tried remanufactured heads was not so good. There were some that had stripped bolt holes and burned up exhaust manifold mating surfaces on the heads....
Jake
 

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Beware of reman heads. If you lean that way, I would highly recommend using a good machine shop. Over the years the times we tried remanufactured heads was not so good. There were some that had stripped bolt holes and burned up exhaust manifold mating surfaces on the heads....
Jake
I was gonna go with ZZPs reconditioned heads but they’re back ordered, and knowing ZZP that means they’re done. The CNC heads are in stock and I know the machine shop is gonna quote me quite a bit more than the 1100 those heads cost. I’ll get the lower matched to the heads and upper manifold gaskets too.
 

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Open it up

Your cramming more air via turbo. Opened it up a bit with cam and exhaust. Not really a restriction but more a missing link I guess .the heads will enhance cam and turbo .vs just heads . I’d imagine if you did get heads a new tune would be a good idea . I’d say min 20 -35 without A tune and current set up . New tune you could play with boost ect then hp gains would depend on how close to the edge you want to be
 

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Well I'm none too happy right now. Went for the reconditioned heads and they arrived today. Looked to be in good shape until I got them under a shop light.

Rust spot near the edge of one combustion chamber, dings on the edge of the CC on both heads and scratches on the sealing surface of one head I can catch my thumb nail in.

They were packed in a box, wrapped in plastic stuffed with tons of packing paper so I doubt UPS could've done this. The heads were wrapped up in plastic with the "Engine Pro" logo on them, so I'm betting they screwed them up before sending em to ZZP. Luckily they have the lot # on them so I'll contact them directly.

I understand mistakes happen but this is a bit of setback for me. $600 on damaged heads and another week without a vehicle of my own.
 

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I would talk to the place that sold you those heads and get them replaced with ones in like new condition.....or, return them for a refund and get heads from a more reputable source. That sucks! A few years ago I went thru two sets of big block ford heads before I got a nice pair. Seems some of these places try to dump off the crappy ones first. No way to conduct business. Jake
 

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To me it just looks like someone was careless in handling them. I'm also not happy they sent me L36 heads when I have an L26 with larger intake ports and valves which ZZP should know.

I'm going to send them back for a refund and go the junkyard a ways from here. They have 2 vehicles in the yard now with the Series III engine so and I can get both sets of heads for $120 as opposed to the $600 I just spent on these boat anchors.
 

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Care

They prob figured you wouldn’t notice like the other 99 people . In my opinion though heads are not where you want to cheap out on .
 

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For the price of the salvage yard heads (both vehicles are the same as mine, one an 06 the other an 08) I can get two sets for $120, still have them magafluxed and shaved if needed and not come close to what I'd spend on reconditoned heads from ZZP.

Given it's 2-3 days shipping to return the heads I'm not waiting around for ZZP to send me a decent set. I also wasn't happy about the valve springs. They informed me the #90 LS6 springs were out of stock and sent the #105 instead, however it looks as if they didn't use oil or any kind of lube to assemble the heads at all. I couldn't get the valve keepers loose to put my stock springs back on the damn things.

I tried penetrating oil along with a socket that fits snugly around the top of the LS1 retainers and give it a good whack with a rubber mallet but they still wouldn't pop loose like my stockers did disassembling my old head. I did all this before checking the mating surfaces and luckily didn't even leave a mark on the retainers. I took my old cracked head and drug it across the cardboard on the garage floor to see if it damaged the mating surface. I doubted it would and it didn't, only thing I did was accidentally ding my old head with a razor blade before I found the cracked valve seat.

Either way, I'm getting it all done asap because I'm waiting on a local machine shop to do a gasket match on my lower intake. I almost went Milzy but this guy has been around for over 30 years, does nothing but race engines and knows his ****. Prob will take a week or two with how his shop is full of engines right now but I'll take that over Milzy who can't even bother to respond to my emails.
 

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I can't believe this. ZZP's heads have been sitting in the garage for less than 24 hours and have already accumulated a considerable amount of rust.

I'm definitely not going to purchase another set from them.

 

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Considering my stock heads that were pulled off have no rust period Im not gonna risk the setback of a 2nd set. In my teardown I discovered a bad rocker I got in the ER Rocker set. Someone drilled straight through the rocker when relocating the pushrod cup and tried to fix it with rather poor grinding of the filler metal. They also drilled a smaller oil hole compared to the other intake rockers which caused more wear on that one rocker than any of the others. I'd say 1/32-1/16 of an inch diffrence in depth. Even with detailed photos ZZP danced around calling it an issue on their end and just said we can sell you another for cheap.
 

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Hmmm

Exchange sure .buy another set lol they crazy .if I knew what I was doing with my car I’d sell you my l67 heads cheap
 

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They said theyd sell a single rocker for cheap. Im ok with that Im just peeved they admitted it could only happen if the wrong drill bit was used then turned around and ask me what exactly I wanted them to do about it like they were shrugging off any adknowlodgement that it was poorly made.
 

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Being an auto tech for EVER, I suspect ZZ does not build these heads. They are pretty much stock and purchased from a reman company. You could probably do better buying a good used set(maybe at a local salvage yard) and having them machined/rebuilt at a good local machine shop or cylinder head shop. When I last bought a set of heads for my GTP, I ended up buying two new bare castings from a local GM dealer and having them machined by a good local CYLINDER HEAD SHOP. No hiccups at all...... If you lived round here I'd send you right over. That said, maybe do some searching for a similar machine shop near you and do the same..... I never looked back and still 100% satisfied along with excellent performance............

Send those heads back, Jake
 

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The heads came in a bag labled Engine Pro which does Remans but they also sell the bags to protect cylinder heads. Even if ZZP didnt make it they wouldve been the ones to install the #105 springs and LS1 retainers which would ve the proper time to do a QC. Compare that with one of the bags being filled with rust particles and I really only see ZZP using the bag. However I will say Im pleased with the valvles as they appear larger than the ones I had in my L26 heads. Ive never rebuilt a head before but everything was installed dry which binded the keepers to the retainers.
 

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Agree

Local machine shop is going to be your best bet . I like zzp ,but returns and customer service are lacking . that’s being generous. Especially since they are pretty big now . As you have found out it’s went from what can we do for you mentality to what do you want us to do about it mentality
 

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Send

I would send both back get your money. back get a used set . Prob have them rebuilt and ported at a machine shop for what you paid at zzp
 

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Discussion Starter #20
So what exactly is wrong with those heads? They are iron so rust with build fast anyway. Clean them up and spray wd-40 on them. The mating surfaces don't have rust so i don't see what's wrong with them. I'm more interested is ZZP's CNC heads not the reman. heads. I'm trying to see if ported heads will gain me much with a Intense S1X turbo cam and a ZZP Z7 kit at 15 psi.
 
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