70-71 LT-1 fuel pumps
There has been much discussion and debate over the years about fuel pump dating. The pump that just didn't fit right was the 40709 pump installed in all 1970 and 90% of the 1971 LT-1 cars (only the very late cars differed.) The LH stamping in front of the 40709 indicated November of 1968, and that didn't make any sense.
I recently was looking at a LH40709 out of a mid-February 1971 LT-1, and in the body of the sealed pump, near the pivot for the actuator arm, I spotted a cast-in "68" with, as best as I can see, 10 small dots around it, which easily could indicated October, 1968.
Based on that, I postulate the following:
1) a large quantity of 40709 fuel pumps were made in November of 1968, in anticipation of the production of the 1969 LT-1, which ended up never happening. (A bit like the '70 LS7 which never made it down the line).
2) GM stored those pumps somewhere, and finally used them a year-plus later, when the LT-1s began being produced in January 1970.
3) Since the span of Julian-dated 40709 pumps that we have documented are from 8K to 86K (January 8 to March 27, 1971), and they are found in cars in the 21000 VIN range (total made was 21801), it appears that Julian-dating began 1/1/1971. My guess is that they made enough in calendar year 1971 to ensure that they didn't run out before end of 1971 production. 1972 LT-1s, of course, used a different pump (40956)
4) I believe the above solidifies that H=1968, I=1969, J=1970, K=1971, etc. (My second-owner '70 350/350 made in March has the original BJ40769 pump on it (Feb. '70)
Let me know what you think about the above.
The "68" was hard to capture. The attached is the best I could do.
.
I recently was looking at a LH40709 out of a mid-February 1971 LT-1, and in the body of the sealed pump, near the pivot for the actuator arm, I spotted a cast-in "68" with, as best as I can see, 10 small dots around it, which easily could indicated October, 1968.
Based on that, I postulate the following:
1) a large quantity of 40709 fuel pumps were made in November of 1968, in anticipation of the production of the 1969 LT-1, which ended up never happening. (A bit like the '70 LS7 which never made it down the line).
2) GM stored those pumps somewhere, and finally used them a year-plus later, when the LT-1s began being produced in January 1970.
3) Since the span of Julian-dated 40709 pumps that we have documented are from 8K to 86K (January 8 to March 27, 1971), and they are found in cars in the 21000 VIN range (total made was 21801), it appears that Julian-dating began 1/1/1971. My guess is that they made enough in calendar year 1971 to ensure that they didn't run out before end of 1971 production. 1972 LT-1s, of course, used a different pump (40956)
4) I believe the above solidifies that H=1968, I=1969, J=1970, K=1971, etc. (My second-owner '70 350/350 made in March has the original BJ40769 pump on it (Feb. '70)
Let me know what you think about the above.
The "68" was hard to capture. The attached is the best I could do.
.
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