I found these carved/machined pieces of wood in the primary fuel bowl on the 4801 Holley on a low-mileage 71 LT-1. Anyone ever seen these before? What would their function be? (two pieces--front and back pics of each)
-
-
Re: 71 LT-1 Holley Why were these in there?
they were also in the 450 HP 454 chevelle engine carbs. they were there to cut down on the amount of fuel in the bowls to cut back on evaporative emissions. they are some type of molded plasticLast edited by Clem Z.; January 7, 2010, 11:04 AM. -
Re: 71 LT-1 Holley Why were these in there?
I agree with Clem. Paul 18046Comment
-
Re: 71 LT-1 Holley Why were these in there?
Put there by GM, or as aftermarket piece?Comment
-
Re: 71 LT-1 Holley Why were these in there?
They are original to the car from the General. Paul 18046Comment
-
Re: 71 LT-1 Holley Why were these in there?
Mike------
I expect they were installed by Holley as part of a GM specification for the carb. However, I've never run across these before, so this is all news to me.
Interesting side-note: I can't find that these pieces were ever available in SERVICE. I presume that they were part of the fuel bowl assembly. For quite a few years, GM cataloged NO SERVICE fuel bowls for 71-72 Corvettes with Holley carbs. Finally, in the late 1970's they cataloged the same SERVICE fuel bowl as used for 65-69 applications. Obviously, these did not contain the inserts. So, apparently, there was no way one could obtain these pieces in SERVICE, either separately or as part of a SERVICE fuel bowl assembly. Whether they were supplied as part of the complete SERVICE carburetor assembly, I don't know. However, since the SERVICE carburetor was the same part number as PRODUCTION, I presume that the SERVICE carbs did contain the inserts.In Appreciation of John HinckleyComment
-
Re: 71 LT-1 Holley Why were these in there?
Yes Joe the over the counter service carb did come with these blocks. I purchase a service replacement back in 1977 for a 71 LT-1 a 4801 list and those blocks were inside the bowls. Paul 18046Comment
-
Comment
-
Re: 71 LT-1 Holley Why were these in there?
I remember seeing a notice, with illustration, about them either in the Holley technical materials or in Chevrolet Service News. They must have started in 1971, because they were not in my List 4555.
Paul, could the over the counter 4801 you bought have a letter or dash number following the part number or list number? I am just curious.TerryComment
-
Re: 71 LT-1 Holley Why were these in there?
Terry------
They MIGHT have been included with 1970 LT-1's with NA-9 and using carb Holley list 4489, though. Given that they were, apparently, part of the EEC system, included only with NA-9 for 1970 but included with all 1971-72, that would seem to "fit".In Appreciation of John HinckleyComment
-
Re: 71 LT-1 Holley Why were these in there?
I agree, and this along with the TI capacitor question in another thread just might force me into the frozen and snow-bound garage over the weekend. If I ever get done shoveling snow.
That probably makes you love California all the more, eh Joe?
TerryComment
-
Re: 71 LT-1 Holley Why were these in there?
Terry------
Right now it's 52 degrees outside with clear blue skies and not a flake of snow in sight. I don't expect to see any, either. I base that on the fact that in 52 years of living in California, I've only seen snow in the "lowlands" ONCE. That was a dusting about 45 years ago that was gone almost as fast as it happened.
We did have an earthquake about an hour ago, though. It was quite a jolt here since the epicenter was nearby.In Appreciation of John HinckleyComment
-
Re: 71 LT-1 Holley Why were these in there?
I was pretty sure Snow wasn't something you were familiar with at home. You guys have to go to altitude to ski on it. At least, unlike the folks to the north and east, I don't have to buy snowshoes. The lake effect is burying Patrick this winter.
Earthquakes and mudslides are not on my list, but floods are -- I think it is all a trade-off. We get some good, and you do too. We get some bad, and you do too.TerryComment
-
Re: 71 LT-1 Holley Why were these in there?
All------
I checked further. There was a special fuel bowl once available in SERVICE for 1970 LT-1's with NA-9 and carb GM #3972123 (Holley list 4489). These were GM #3979502, primary, and GM #3972540, secondary. These were never cataloged for the 1971-72 LT-1 applications but I have a hunch that they were the ones used.
Strange thing about these fuel bowls: in the early 70's when Holley fuel bowls for most applications GM listed for about 37 bucks, the aforementioned bowls carried a GM list of only about 11 bucks.
Both the 3979502 and 3979540 were discontinued without supercession in October, 1977.In Appreciation of John HinckleyComment
-
Re: 71 LT-1 Holley Why were these in there?
The 1970 NA9 primary fuel bowl had a vent pipe that connected via a hose to the evaporative emissions canister in the driver's side fender. A "feature" that the non-NA9 fuel bowl didn't have. I am not sure what external differences, if any, there might have been for the secondary fuel bowls.
At the risk of confusing the issue even more, there was available a plastic part to go inside the fuel bowl(s) called a "whistle" because of its shape. The purpose was to keep sloshing fuel away from certain areas inside the fuel bowl, especially during acceleration. It was shaped differently that what Mike Ernst showed, and served a different purpose. I don't know if the "whistle" ever came OEM or was strictly something that had to be added after the fact. I expect Clem would know more about that.TerryComment
Comment