What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1 ?
According to the NCRS Judging manual the 1970-71 LT1 should have the following radiator hose numbers. Lower - #3946854 JQ AU, the upper shows #3946852 JP AU and also shows #3959554 (late 70). Well my questions is, what would the correct UPPER HOSE be for a late 1970 LT1 or a very early 1971 LT1 that was built in August of 1970? would it be the #3946852 or the #3959554? Any thoughts? Thanks, Tom
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Dave,Gary, OK so if the 3959554 is correct for the July 1970 LT1, would you have any thoughts on the correct application for the 3946852 upper hose? Maybe as to when they might have started to use the 3946852? The LT1 was made in 70, 71 and 72. Was the 3946852 the replacement style and number for the later cars? TomComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Right now, I don't have a 71 or 72 LT-1 with a copper radiator here. Have two LT-1's with aluminum radiators, I'll let you figure that out :-)
It's a $100 trip now for me to go look a building full of other cars. Toll road and $5.90/gal for diesel. I'll add this to my list of things to look at, next time I go in. I'll also ask a few of the TIM&JG revision team to look at there cars.
Patience please.
Gary BComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
My early july 70.
Screenshot_20220705-173151_Photos.jpgComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
This radiator hose if off a 1971 with a VIN under 000075 and has a trim date code of A17-August 17th. What I can see the number is 3946852.PAT, Central New Jersey and Florida Chapters
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
OK, I appreciate all the help from everyone to try and figure this out. I went back and looked at my vintage GM 1953-1973 Corvette Parts Catalog, which was a revision from 7-73 and from what I can determine is the following. the upper hose # 3946852 as correct for the 71-72 Corvette w/Sp H/Per (350) LT1. It also shows that #3959554 is correct for a 1970 Corvette w/Sp H/Per (350) LT1. It appears to me that the 3959554 was for only the 1970 LT1 ?? I have attached as photos the pages in the GM Corvette Parts Catalog the i am using. If there is anyone who has a 1971-72 LT1 with original upper hose that could verify this would be appreciated. Any photos would also be helpful. Thanks, TomComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
I have received data from (5) original, unrestored cars with original upper radiator hoses. It appears early 1970's used the 3946852 upper hose on the copper radiators. Sometime in mid production ?? 1970 they switched to 3946854. Sometime after July 7th, 1970 and into early 1971 production GM switched back to 3946852. Later production 1971 and all of 1972's used 3946854 hose. The 70-72 TIM&JG Fig. M21.16 shows a 3946852 from a Jan. 29th, 1970 car. Pat Fullam posted a picture of his 1971 with a 3946852 hose, with Vin lower than 0075. I might steel that picture and use it in the 70-72 TIM&JG.
Your original question was... "what would the correct UPPER HOSE be for a late 1970 LT1 or a very early 1971 LT1 that was built in August of 1970? would it be the #3946852 or the #3959554? "
I would use a 3946852 based off Pat's car. His picture shows an original hose !!
"We will" continue to look for better breaks on the usage of each hose. I'll pay more attention while judging. I'll also update the 70-72 TIM&JG with what we know today, make it a little clearer.
Gary Bosselman
70-72 TIM&JG CoordinatorComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Gary, seems a bit confusing to me because the 3946854 that you state is actually a lower hose not upper hose?? and the photo of Pat Fullam with the 3946852 hose appears to be of an early 1971 but with a base motor not an LT1 ?? I am mainly concerned with the LT1 correct hose. I would say that the early 70 LT1 used the 3946852 upper hose , then GM changed to the 3959554 upper hose probably in mid 70 production of the 70 LT1's , that's why it says (late 1970) in the TIM&JG , and then went back to the original of 3946852 for the later 1971's and all 1972 LT1's. Would you have any idea of when GM possible made the change back to the original upper hose 3946852 for the later 71 LT1's and all of 72 LT1's? what are your thoughts? I am getting this right? Again, I am just trying to figure the correct upper hose number for the LT1's and when the changes were made. Thanks, TomComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Does this sound right??
1 Early 1970 LT-1 engines used a 3946852 upper hose. (See Fig. M21.17) Sometime in mid-1970 production GM switched to a 3959554 upper hose, and used this hose through at least July 7, 1970. Sometime between July 7, 1970 and 1971 Vin 0075, GM switched back to 3946852 upper hose. This hose, was used through the remaining 1971 and 1972 production.
Gary Bosselman
70-72 TIM&JG CoordinatorComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Gary, yes! I think that is correct now. I have a friend that has a late 1970 LT1 ( not exactly sure of it's build date, it is July 70 something, but I'll find out ) and his LT1 has the 3959554 upper hose. I have an early 1971 LT1 (Sep 4, 1970 build date) and it has the 3946852 upper hose. That is the reason that I started to inquire about which upper hose number is correct and when they were used. Thank you for all your help. TomComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Let me know what the 70 build date is please. Jim looked at his two 71's, both have the 6852 hoses, but are later cars. Gary Craig's 71 is 6852. All are original unrestored cars with original hoses.
Appreciate your help!
Gary BComment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
And my 71 is a Sept 11 1970 build and has the 6852 upper hose.Comment
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Re: What is the correct upper radiator hose # for a late 1970 or very early 1971 LT1
Gary B, the build date of my friends LT1 is "G29" Jul 29, 1970 , last six of vin - 416991Comment
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