I agree with Tim's post regarding the long rod issue.
I'm of the opinion the increased popularity of the longer rod in a Pontiac situation came about with Jim Butler's involvement probably 30 or more years ago with his collaboration with the Eagle crank deal. And related, within his articles in Pontiac Enthusiast magazine back then he mentions his use of the 4.250 stroke crank and 6.8 rods, along with his custom JBP Ross pistons. It increases the displacement of the 455 engine. At the same time, the better rod angle, the improved rod-to-stroke ratio of 1.6:1, and the raised pin location in these custom pistons relieve the stress on the block. The higher pin pushes up on the piston instead of out on the skirt and results in less friction.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 )
Old information here:
http://www.hotrod.com/articles/0712p...tiac-trans-am/
Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE
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