A.L.DUNN heads...........
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Race Director
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From: Fremont Ca
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A.L.DUNN heads...........
Ive noticed an optoin on 95? ZR1s that state they have A.L.DUNN heads.What is this option and was it only offered on 95s.Thanks
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Re: A.L.DUNN heads........... (z51jeff)
Not an option just a change some 95s had only one late 95s had R&L
Melting Slicks
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From: Construction Sucks! MI
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Re: A.L.DUNN heads........... (We Gone)
http://www.zr1.net/ZR1_faq.html#heads
edit: in case the link doesn't work this is what it says:
All the engines were produced substantially before the 1995 and about 1/3 the way into the 1994 production periods (i.e.., Fall of 1993). The motors were stored at the plant and assembled into the cars by some methodology known only to the guys who brought them to the line. There is no guarantee the last 1995 cars built got the latest engines built, or that some of those engines may not have found their way into earlier serial number cars. Also, some motors went to SPO for replacement or sale requests while cars were being built. As we all know, many other engines made their way into the public's hands.
So, the only way to determine if a car has A.L. Dunn heads, is to be able to recognize them when you examine the car. Vehicle production S/N is no guarantee. To see if you have Dunn heads using a mirror look for a triangular shaped tensioner cover on the passenger side heads with 3 bolts and a center adjuster that lies under the cam cover. Look for a little casting mark with a mirror just under the cam covers of A.L. Dunn heads - left of the dipstick as you look through the wheel well on the passenger side. You will see a sort of rolling scroll (a similar font is bauhaus 93 if you look in WORD or AOL) that reads "dunn" in all small letters; and then what appears to be an "l" on the left side head, and an "r" on the right side head. The Dunn casting mark is also present on the driver's side in about the same position
Also, it is possible to get one head of each design from SPO if you order a replacement pair. They don't open the boxes when the heads are shipped to see if the surfaces are machined or cast. There is also no part number difference between the two heads. GM's rationalization is there is no performance difference.
[Modified by 86_RedRider, 12:50 PM 1/29/2004]
edit: in case the link doesn't work this is what it says:
All the engines were produced substantially before the 1995 and about 1/3 the way into the 1994 production periods (i.e.., Fall of 1993). The motors were stored at the plant and assembled into the cars by some methodology known only to the guys who brought them to the line. There is no guarantee the last 1995 cars built got the latest engines built, or that some of those engines may not have found their way into earlier serial number cars. Also, some motors went to SPO for replacement or sale requests while cars were being built. As we all know, many other engines made their way into the public's hands.
So, the only way to determine if a car has A.L. Dunn heads, is to be able to recognize them when you examine the car. Vehicle production S/N is no guarantee. To see if you have Dunn heads using a mirror look for a triangular shaped tensioner cover on the passenger side heads with 3 bolts and a center adjuster that lies under the cam cover. Look for a little casting mark with a mirror just under the cam covers of A.L. Dunn heads - left of the dipstick as you look through the wheel well on the passenger side. You will see a sort of rolling scroll (a similar font is bauhaus 93 if you look in WORD or AOL) that reads "dunn" in all small letters; and then what appears to be an "l" on the left side head, and an "r" on the right side head. The Dunn casting mark is also present on the driver's side in about the same position
Also, it is possible to get one head of each design from SPO if you order a replacement pair. They don't open the boxes when the heads are shipped to see if the surfaces are machined or cast. There is also no part number difference between the two heads. GM's rationalization is there is no performance difference.
[Modified by 86_RedRider, 12:50 PM 1/29/2004]
