[SS4Real]

Here's a correct summary of 1970 Chevelle SS Tach's. Ultimately, you must look at the car's original build sheet to verify which tach came in the car (not all SS Chevelles came with a tach but all SS Chevelles had the round dash pods). You begin by looking at box 107 of the build sheet to see if the car came with the U14 IP Gauges option. If it does have the U14 IP Gauges option, then your next step is to look at box 72 to see the code for the tach in your car (if your car does not have the UP14 IP Gauges, then you will have --- in box 72 which means no tach). After looking at the code in box 72, here is the breakdown of the tachs that came in the 1970 SS Chevelles:

L34 396/350 hp 5500 rpm tach code 985
L78 396/375 hp 6500 rpm tach code 983
LS5 454/360 hp 5000 rpm tach code 938 ****or****
LS5 454/360 hp 5500 rpm tach code 985
LS6 454/450 hp 6500 rpm tach code 983

It's also possible that some cars **may** have come with different tachs due to different assembly plants or parts shortages. Again, ultimately to prove that exception you would need an original build sheet to see what code is in box 72.

Atlanta built LS5's commonly came with the 938 5000 RPM tach and some Baltimore built LS5's did as well. Again, you have to check the code in the build sheet (if available) to verify.