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Join Date: Aug 2004
Location: Nanimo, B.C. Canada
Re: Street Duty Solid Roller lifters and Tall Deck BBC question?
Interesting question. All the aftermarket blocks that are now available, and the newer Bow Tie block have raised/enlarged lifter bosses that allow .300"taller lifters. The taller lifter bosses reduce side loading on the lifter body.
Aftermarket tall roller lfters have a taller lifter body, but I'm not sure that the pushrod seat is relocated the same amount. In fact, I think the height of the pushrod seat in relation to the centerline of the lifter axle is very close to stock height lifters, but it varies slightly from one company to another.
For example, a 10.2" tall deck block would normally need 8.685"intakes and 9.656" exhuast pushrods. In my case, using a 10.2" Dart block with Crower tall body roller lifters and AFR heads ( which normally require .200"" or slightly longer pushrods) I would nedd something near 8.885 Int and 9.856"exh. If you subtracted the .300"for the taller lifters, it would be 8.585 / 9.556 pushrods. After measuring I actually needed 8.850 intakes, 9.750 exhausts, very close to the original estimate without taking the tller lifter body into account.