Quote:
Originally Posted by CobraEd
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Most Chevy books give me a headache too
Ford 400C rod..........................= 6.580"
Ford 351w crank (1/2 stroke......)= 1.750"
Piston for 331w stroker, pin height= 1.165"
Total stack height of combination.= 9.495"
Late model 351w deck height.......= 9.500"
As an aside to this I built a 200cu in straight six Falcon to compete alongside a 202 cu in Holden straight six many years ago. Holden was 3.25" stroke with a 5.25" rod ( 1.61/1 Rod Ratio), Falcon was 3.125 stroke with 6.25 rod (2.0/1) rod ratio.
Series tech guys insisted we initially run the same cam specs, with this the Falcon idled like a baby where the Holden had a distinct lopey idle...just as the article you posted suggests- with the long rod the piston is 'parked' @ TDC during the cam overlap phase that the scavenge effect is virtually killed off at low RPM, now while some might say this was a negative it worked fine in this car & it was competitive from day one...later I plotted out the piston dwell @ TDC versus valve overlap & transferred this on to a 'new' cam profile to suit the Falcon. The Holden guys were not amused
I should point out this was the 'old' cast in head inlet manifold Falcon engine, not the later seperate intake setup.
So, in all the long rod 351 should idle more smoothly than its short rod version given the same cam /head etc, but have a bit extra at the top end.