Keith,

I know there is some 'sweet spot' in the powerband that favors that tight separation, I'm wondering have you done testing of larger cube motors with small (stock or near stock) exhausts? I've almost always seen that the overall powerband is broader ( though maybe not in terms of absolute 'peak" torque) with a wider spread.

A good example comes to mind with AndyF's 470 motor running stock ehaust manifolds, of all the cams he tested the old .single pattern MP528 with a 112 split worked best. The tight 'sweet spot' of torque you speak of logically has to cost you some horsepower ( literally the motor's ability to gain rpm past the VE peak) on the top of the range, and of course (as Andy also found out) the induction side is impacted as well. Sidebar: WAY too O/T to get into here but the VE curve in terms of keeping the crank from slowing (rpm/sec) after peak torque helps keep the induction charging, a peakier curve means the crank is slowing at a faster rate after the peak, not an issue with Good heads but when they're not.... We need to talk over a few Barley pops some time ;-)

I know a number of Stock eliminator and even circle track combos have a very narrow "sweet spot" and they do their best to optimize the car dynamics around it and a degree or 2 of cam timing the wrong way really screws things up to where it won't fall out of a tree. I agree with you in terms of peak that a narrow spread can usually peak higher SOMEWHERE in the powerband, I've just not seen very many that can hold a better average curve (VE) typically falls quicker after the peak. It's all what your after and what class limitation (ex: FAST) you have to contend with. All the motor combos and even porting techniques play a big role unmaking a combo work....or not.

Also overall drivability and especially weight and gearing can come into play, if your running a 416 with stock exhausts and an OD trans with a 2.94 final drive I'm not sure I'd go 108 centers even if the torque peak was slightly higher for need of a smoother more tractible low RPM roll on. Also individual intake/exhaust duration specs can have a near equal effect on effective overlap than the physical spread itself.

I've worked on and consulted on a lot of 'stealthy' combos over the years, nothing surprises me much anymore....except Buicks



Sorry to get so O/T !!!