Posted March 15, 20231 yr comment_651409 I have a question and a problem. I'm doing a 73 restoration that was an auto. I'm changing it over to manual with 72 round top carbs and intake manifold. It appears the carb linkage arm that runs from the firewall bracket to the intake manifold are different lengths. I looked on the micro fisch and it does not indicate that they are different. The mfg date on my 73 is 3/73 not sure the mfg date on the 72 (I only have the engine & trans). Attached are two pics. The yellow one is the original one on the 73 connected to the flat tops the silver one it the same linkage arm attached to the 72 round tops. Note the spacing between the firewall bracket and the upright angle bracket on the linkage arm. Comments, suggestions, resolutions greatly appreciaated. Thanks Paul (z3beemer) Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/ Share on other sites More sharing options...
March 15, 20231 yr comment_651415 The linkage piece that mounts in the balance tube is very different between the round tops and the flat tops including the location of the slot where the shepherds hook connects. The round tops require a longer shepherds hook. I'm not an expert at reading the parts fiche, but it seems to me they did use different parts. Goes like this: 12 ASSY-TORSION SHAFT A 18300-E4600 L241 18300-E4601 L24 7206 18300-N3300 L24 7207-7307 18300-N3600 L26 7308-7408 18300-N4310 L26 7409 I'm thinking you're looking for 18300-E4600 or E4601 which were used until 6/72. Your car came with 18300-N3300 which started in 7/72. Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651415 Share on other sites More sharing options...
March 15, 20231 yr Author comment_651425 Thanks for the input. I guess I'll post in the want ads and see if anyone has a linkage arm from a 72. If not I may be able to cut the one I have, and weld a section in to make it longer. I can also weld a short stub on the shepherd hook. If I can't find one, I may need to call on the group to get a few dimensions. In the meantime, if anyone has a linkage arm from a 72 (round top carb), let me know. Thanks Paul Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651425 Share on other sites More sharing options...
March 15, 20231 yr comment_651433 7 hours ago, z3beemer said: I may be able to cut the one I have, and weld a section in to make it longer. Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651433 Share on other sites More sharing options...
March 15, 20231 yr comment_651435 As some guys here know, i'm also here to learn some english writing.. 😉 Hey Paul.. read your paper on the engine in the first pic.. hihi.. what kind of linkage? I don't have a good answer on your question, but overall.. there are A LOT of differences in these cars parts.. sigh.. Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651435 Share on other sites More sharing options...
March 16, 20231 yr Author comment_651466 Well, I decided I'm going to try to weld an extension in the one I have. Can anyone who has a 72 Z with round top carbs provide me a few dimensions? I would need an overall dimension from the top of the shepherd hook to the end of the rod, and a dimension from the top of the shepherd hook to the end of the hook (the part that connects to the carb linkage). Thanks in advance. Paul Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651466 Share on other sites More sharing options...
March 16, 20231 yr comment_651470 IIRC the 73 part was shorter, because of the EGR set up. Do you have the old one from the 73 to measure? I have two, one is 12.125" the other 12.5" overall. Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651470 Share on other sites More sharing options...
March 16, 20231 yr Author comment_651471 The one from the 73 is 10.75" Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651471 Share on other sites More sharing options...
March 17, 20231 yr comment_651495 You can get a rough idea of the difference between the two by looking at where on the intake manifolds the joint between the parts lands. Use the intake manifold and/or carb mounting bolts as reference markers. Using hoovered pics: Here's the flat tops. Note that the linkage joint is about the center of the rear carb: And here's the round tops. Note that the joint is further forward requiring the longer linkage piece: Link to comment https://www.classiczcars.com/forums/topic/68195-carb-linkage-arms-are-they-different/#findComment-651495 Share on other sites More sharing options...
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