Lower exhaust, lower transfers, compression, etc? More than one way to skin a cat. For instance when I ported a 241 i gutted the strato and raised the transfers to about 120 and had great lean on. I couldnt leave well enough alone so I took them on up to 117. That was a mistake. Still cut good but killed the lean on and every 241 Ive seen has great lean on from the factory. U can definetely make a turd as I learned and u know this for sure as u have a ton more experience than I do and that I respect u for. Ive ported a few myself to know the difference in one than can be leaned on and one that cant