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Author Topic:   lifters
Dirt Forum Racer

Total posts: 87
posted October 29, 2003 05:28 PM  
how much vacuum can you gain by changing lifters to duration lifters. sbc 58cc heads comp cam 114 lob center 477 480 lift. it now pulls 15 inches and need 17

rico 08
Dirt Forum Champ
Total posts: 1139
posted October 29, 2003 10:23 PM  
I you are referring to crane style variable duration lifters and rhoads lifters they will probably give you the extra vacuum you need,also some tuning may help too.

Dirt Forum Champ
Total posts: 823
posted October 29, 2003 10:30 PM  
I would ask a engine guy, my understanding on those lifters is that they dont pump up at higher rpms thats it.

Dirt Forum Champ
Total posts: 635
posted October 30, 2003 02:28 PM  
The Crane lifters seem to help our motors idle a little smoother. We don't have a vacuum rule, but it seems like it smooths out some and ticks almost like a solid would. They're claimed to reduce duration 8 -10 degrees below 3500 rpm. From my limited experience with them, seems to work.

rico 08
Dirt Forum Champ
Total posts: 1139
posted October 30, 2003 03:10 PM  
66jj is right you never seem to get all of it back,car craft did a test a while back and they did give more vacuum but were not as strong in the higher rpm's.But for a vacuum rule class you do what you gotta do.

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