Ok i need to make a decision. 3.25 or 3.5 diff centre. Details are: XY, 366clevo, 750dp, funnelweb, ported 2v's, 624"lift cam with around 252-259deg duration @50". 4into1 pacys with twin 2.5good flowing exhaust. Backed up by a standard ratio toploader. Ive got 4.11's but want to do more highway cruising to the coast and stuff. 3.25's would be good on the highway but not shure. what would people recomend. Would 3.5's still be a touch to much for the highway? I like the sound of 3.5's because id still get a pretty good take off. However on the highway with 3.5's id be doing 3000rpm at 65-70mph.? What are peoples thoughts, comments, experience?
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Just love that V8 sound, rumble, music!
Ok i need to make a decision. 3.25 or 3.5 diff centre. Details are: XY, 366clevo, 750dp, funnelweb, ported 2v's, 624"lift cam with around 252-259deg duration @50". 4into1 pacys with twin 2.5good flowing exhaust. Backed up by a standard ratio toploader. Ive got 4.11's but want to do more highway cruising to the coast and stuff. 3.25's would be good on the highway but not shure. what would people recomend. Would 3.5's still be a touch to much for the highway? I like the sound of 3.5's because id still get a pretty good take off. However on the highway with 3.5's id be doing 3000rpm at 65-70mph.? What are peoples thoughts, comments, experience?
3.5 is a good ratio for launching without frying tyres rediculously easy and is great around town and on the circuit. It does not drive me crazy as long as you are only sitting on or around 100km/h; sitting on 120km/h drives me crazy.
True that 3.25 will be better for the highway but with your cam duration the 3.5's may be more suitable(drivability).What RPM are you happy for it to rev on the highway?
I would say go for the 3.55:1...because if you are using 4.11:1 now,then this will be considerable relief for highway cruising.Going back to 3.25:1 is a fairly dramatic move after using your current ratio,the 3.55:1 will give you some kind of practicallity,while still retaing some launch capablities.
i have a set of solid 4.1:1s and a lsd 3.0:1 .
i use the 3s most of the time , great when your out cruising long trips on the open hwy but a bit fast for around town .
i think that if you are going to be doing more open road driving , 3.25 .
or if you will still be doing a lot of town cruising the 3.5 would be more fun.
the 4.1 i fit if i`m going to get serious.
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dave
`75 XB FAIRMONT SEDAN injected 351, toplaoder, disc brake 9", factory paint+ vinyl roof.
`03 BA XLS ute - lpg, auto, lsd, acid rush paint,
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Ok. Thanks for the comments fellas. Ive always been keen to go the 3.5's. But the old man recconds 3.25's but then he's always really conservative and see's things a bit differently. I'm gona be keeping the 4.11 centre for the strip. But i think the 3.5 might still pull alright times and then i can just drive their and race. It would be a bugger changing centres at the track. I will see what revs it'll sit on on 100kph with 3.5s and see if im happy with that. Cheers fellas.
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Just love that V8 sound, rumble, music!
I find it useful to be able to calculate the revs you'll be pulling using different combinations, this way you can match everything to suit the cam's power band.
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