I understand. I've gotten so many different answers on them that I think that I'll avoid them. I have those 2 A bodies to check out soon and I'm planning on buying one of them and doing a mild cam upgrade sometime over the winter
Because the cam to crank centerline is further apart on the SBM (further apart than a B or an RB) I always used a tensioner.
Is there extra friction there? Sure. Buy a better oil.
And think of it this way. Does the increased friction cost more power than wonky cam timing? I suggest it does not. That little bit of friction is a cheap price to pay for accurate timing.
Of course, if you are that concerned with accurate cam timing you need a fixed idler gear drive. Unless you find one used you won’t get one for a price anywhere near what a TC&G cost.
I eat the cost and use a gear drive. I’m a buy once, cry once kind of guy.