Interesting, it seems that a lot of people think seal conditioners make things worse if you stop using them. I doubt a seal would become harder/worse after a product(oil or additive) is used, and discontinued. I'd expect the seal to at worse return to the original condition.
With my oil usage in the one 302, I have to add something between oil changes. I usually add an additive about half of those times, I like the STP version for reducing leaks and smoking, but it used to be $4(now it's over $8(too much)). Rislone makes one I often have on hand, Lubegard has one($12 per usage), and Lucas also has a quart version that sounds good. I rarely add anything to my engines that don't use oil, very rarely. I've tried the old typical slick products, with no gains. For this work vehicle I'm justifying the extra costs for now. In Spring I'll get to doing the trans/TC, exhaust, and then the swap rebuilt heads onto it(GT40 and do the log manifolds). With new heads it should stop using oil(new front and rear seals earlier).
Go at leaks methodically, they can be conquered. I've solved them on every used car I've owned.
