238 B-R versus 293 B-R ignition coils

[Scott Sims]

For 1970 454 Corvettes there is a listing for 293 B-R ignition coils without TI. There is also a listing for 238 B-Rs but that listing says 'with TI'. Then 1971-1974 lists the 238 B-R as common on a variety of GM vehicles without electronic ignition, not TI. What is the difference between the two? I don't have TI on my '70 454 so it would be a 293 B-R, right? But let's say I change my original distributor to the new HEI with mechanical tach drive. Would I then need the 238 B-R?

Thanks,
Scott

[Joe L.]

Re: 238 B-R versus 293 B-R ignition coils

Scott-----

I'm not familiar with the '293' coil. It may be a 1970+ application. If so, I suspect that it was one of the coils used for big blocks, either for standard ignition or TI ignition. The number would be as I described earlier and would be the part number for the coil + bracket assembly which is how big block coils were generally supplied to the assembly line. The coil, itself, would be the same as that used for small blocks of the same ignition system.

If you change to an HEI type distributor which has been converted to tach drive then you don't use any of these coils. The 75+ HEI distributors use a different type coil which is attached to the distributor cap and is of GM #1985473.

[Scott Sims]

Re: 238 B-R versus 293 B-R ignition coils

Joe, you are correct. I once had an HEI on a previous Corvette and there was no coil. The one question I really wanted an answer to is what is the difference between the two coils. Does one emit more electrical charges or more frequent charges or stronger charges over the other?

Thanks,
Scott