>At 08:09 AM 7/12/2002 -0500, you wrote: >is all this talk going on the assumption that all the comparisons of >vehicles are using the same rear end ratio? that will make a difference in >off the line snap. > > mo jo Almost Imperials from 1959 had 2.94 gear ratios (its actually 2.9375, quoted as 2.93 early on). There is a 1961 CarLife road test somewhere in the site (413) where a 3.23 gear ratio was used, and certainly helped acceleration. The 3.23 413 Imperial was still a bit slower than the 2.94 67 440 Imperial (which also had larger tires). >Also, is it possible that the casting mass and cylinder wall thickness >contribute to quieter operation? Certainly it won't hurt, but most of the engine noise is coming from the intake and the exhaust, so I am not sure if this will make any significant difference. >but wasn't the 413 >originally intended to be a smooth, quiet, powerful piece for Imperials and >the like? Well, I know for sure that certain 413s on Chrysler 300s made excellent high performance engines that surpassed the earlier hemis. The ram manifolds and large cams produced some seriously powerful engines energizing 300F's and G's to some very high speeds, in spite of the cross ply tires and relatively low gear ratios. It seems that the 413 was a fine engine, no doubt. But if the 440 had certain shortcomings against the 413, my opinion is it was an overall improvement. >And if I'm all wet, why did they continue to use 413's well into the 70's for >medium duty truck use? Why not just use the common 440 at that point? Is it possible that there was an inventory of left over 413 parts and blocks which had to be utilized? D^2