Difference in 273

Great info. on valve springs guys . Thank you very much.:thankyou: Love to learn even at my age.lol
Always thought 2bbl & 4bbl 273's used the same springs but checked my service manual also and low and behold there is info krazycuda posted. Since I have a set of 4bbl heads( on car ) and 2bbl heads ( laying in garage ) to compare that I'm pretty sure are both original. Checked this morning and the springs sure look slightly thicker to me on the commando heads than 2bbls.