Hey Peo! Wow that's a cool ride! I've been told that old Caddy's like yours had the engine basically "blueprinted" from factory. I.E. each cylinder bore measured, then pistons made in fractionally different diameters installed to match each cylinder. I've heard stories of old Caddy motors having monumental torque. Also I bet the compression ratio is well over 9 to 1.
So--dialing in that beast better than stock--no surprise you can break the tires loose on corners or otherwise!
I wonder how you Grooved that carb without Ron's bits. I know that off-the-shelf bits shaped like Ron's dont exist, I consulted w/ a master machinist, he'd never seen anything like 'em. I was wanting to Groove the iron throttle body from my Subaru carb w/o risking our valuable bits. In the end I had a certain industrial bit modified, used it to begin my Grooves, then finished with the small one from Ron. Interesting thing was how easy it was to cut iron! Mine was actually easier to control during cutting than any aluminum throttle body ( who woulda thought?
)
I have a 5-cent question about the Groove and it's interaction w/ engines. Has to do with ratio of cylinder bore to stroke also rod angles. Would engines w/ bore legnths (swept area of cylinder-how far piston top descends in bore at bottom dead center) greater than bore diameter-also called "stroker" engines---would that be better than the reverse bore/stroke ratio. In other words does the greater distance pistons travel in "stroker" engines increase the vacuum pulse generated in the intake stroke, compared to the vacuum generated in an engine of same displacement with larger bore/shorter stroke?
I'm reasoning here that the longer piston stroke creates a faster piston acceleration since the piston must descend a greater distance during the same amount of time compared to an engine w/ shorter stroke. Seems to me since the intake vacuum is generated by that piston descending during the intake stroke--the faster it moves per unit of time the stronger the vacuum signal would be. But also the vacuum's intensity is also governed by how far open the throttle is. More the throttle is closed the stronger the vacuum is. So the long-stroke faster piston-speed engine should have stronger vacuum pulse off idle, so goes my guess here...?
If I remember correctly, Peo, I think those old Caddy motors had a longer stroke than cylinder bore diameter, plus they were basically factory-blueprinted. I don't know if anyone else knows their facts about the Caddy engines' specs. Or if anyone more knowledgeable can weigh in about my piston-speed to manifold vacuum ratio theory...I'm pretty sure other factors are involved like valve diameters, manifold design, etc. I do remember that those old Caddy's had gobs of torque, to rival anything else from Detroit in those days.
Another factor in engine dynamics is rod angle. In other words, when the piston is at the halfway point going down the bore, how far off vertical is the connecting rod? I remember reading in some Mopar-related magazine years ago, that the Chrysler 440 cu.in. engine had one of the very best rod angles, meaning that at 90 degrees after top dead center crank rotation, where piston is halfway down the bore, the point where the rod is at it's greatest angle offset from vertical straight up-and-down, the 440 had a shallower angle. Less angle offset from vertical the rod has here, means overall less stress on cylinder walls, pistons and rings. Meaning longer engine life, better ring sealing, etc. I'm gonna common sense guess here, therefore, better vacuum generation as well.
I dont know at all what the bore/stroke ratio or rod angle (or rod ratio, that's another thing) are for your Caddy. Whatever we have or are working on, that stuff is already "baked in". But things like this I'm sure are part of why some engines respond to the Groove better than others!
Well if you have made it this far and are still awake, thanks for suffering through my thinking with my fingers, Peo! PS-any pics of your Caddy project and of your Groove job(s) would be cool!
TracyG Gadgetman Reno