B3 racing engines

Not knowing better, I'm assuming the pushrods need to be swapped too? Will they need to be measured and made custom to fit whatever the combo is? Or is there some fixed number 'longer than current' (example: add .180" to your current length), or do they simply get re-used? All the logic and engineering makes sense, and it seems a prudent upgrade for anyone with roller rockers or non-stock cams.

Yes, you will need longer pushrods, but a well built motor will almost always need a custom pushrod length anyway. It needs to be measured after the correction is made, and I always recommend running the longest pushrod possible.