Terrance P. Perryman
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What problems did the early GN1 heads have?
What problems did the early GN1 heads have
- Thread starter Terrance P. Perryman
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For daily drivers I dont think that there were many issues, i think it was more driven towards racers trying to push the limits. I have seen of cracks between spark plug holes welded up and then their decks were beefed up for strength. My early set came off of a car that was running 9.7 and 9.8's with the Scorpion pedestal mount rockers. No serial ( casting) numbers but still in excellent shape. I dont know exactly how much futher they could have been pushed without damage. I am sure others will chime in as the may have been running the shaft mount rocker setup which should be more stable. My setup is a 14 bolt set that has been on an off center stage block it's whole life. 8 bolt heads were common also.
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14 bolt lasted just long enuf to drive to the dyno.....made no pulls as the coolant was dripping out of the 4" crack.
Total junk. But, the upside was, it only took 15 weeks to get them "repaired".
Total junk. But, the upside was, it only took 15 weeks to get them "repaired".
Terrance P. Perryman
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What about the 8 bolt heads on a daily driver with limited track time?14 bolt lasted just long enuf to drive to the dyno.....made no pulls as the coolant was dripping out of the 4" crack.
Total junk. But, the upside was, it only took 15 weeks to get them "repaired".
strungout6
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How can you tell if they are the "early" heads or not. Im running a set of GN1 aluminum's 14 bolt on a 109 block with the stud style scorpion rocker arms. My car was in boxes when I bought it and these were in the pile of stuff. So far I have had no issues. ARP studs and cosmetic gaskets.
strungout6
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Yup, mine are the same way. Now I am curious on what head casting I have.
Terrance P. Perryman
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I think these heads were the early production made between 2000-2005. I seen where Bison inquired abou
Terrance P. Perryman
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I think these were purchased between 2000-2005. I heard that the early production heads were prone to cracking. I don't know if they were referring to the 8 or 14 bolt heads.
750H.P.V6
Brutal 6 Racing
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Terrance,
Give me a call and I can give you the low down.
Neal
Give me a call and I can give you the low down.
Neal
These were the early casting, right Chuck? My engine builder bought mine last year, new casting, and had no fears about putting them on my very expensive rebuild. You may know my engine builder, Dave Roland.14 bolt lasted just long enuf to drive to the dyno.....made no pulls as the coolant was dripping out of the 4" crack.
Total junk. But, the upside was, it only took 15 weeks to get them "repaired".
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Yep...The 2nd set wasn't much better. They didn't crack, but the valve seats sunk/came loose.
Under what conditions? Heavily raced motor or a street/strip or both? Just like to know what I'm in store for.
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Street engine. 274". 116 race gas at all times. Only a couple track visits. Never over 22# boost..
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I'd not do that.........
My wife would kill me if I tried to sell the car. I'll keep the TT Street Tune and just enjoy cruising.
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I wouldn't sell it either. If the heads that you got last year were new from a vendor I wouldn't be worried about them at all. I think the heads in question probably pre date 2004 maybe even 2000. I dont know exactly when the problems went away and I was sort of hoping someone that was reading this thread had a receipt or date of purchase that could narrow down when the run of great heads started. I have a set of 14 bolts ( no serial #'s on the intake valley) with the red Scorpion 1.65 pedestal rockers that has been on an off center 4.1 stage 2 ( 256 cu in) since 01/02 that came from Bowling Green Customs. They have never been pushed faster than 9.74 in the 1/4 and have ran in the 9.8s regularly. This car was a daily for a few months also a few years ago, the motor was pulled to be freshened up and those heads will be inspected in the coming weeks.
Thanks. I talked to my engine builder about GN1 heads and he said the issues of the cracking were addressed and that no other new issues had popped up since the "redesign". However, I should have gotten TA heads. Even my own engine builder said they have the potential to outflow GN1s. I will probably never push my GN1s to their full potential. I'm just trying to get into the high 10s. Originally the goal was low 10s, but I've been told that my block might not live long pushing it that hard because the weight of my car which was over 3800lbs with me in it. It may have lost 30 lbs or so switching to the GN1 heads. 3770 is still pretty heavy.
