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help me decide 3.45 or 3.7

v8_bomberdore

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i want to do the diff gears im my vp v8 auto but i dont know what to do , i was thinking either 3.45 or 3.7 what im worried about is if i go to 3.45 it might not be enough then ill wish i had of went 3.7s, but then if i go 3.7s im worried it might be a bit much , i do a little bit of highway driving but not alot , im looking for a bit more punch off the line and wen cruzing, im leaning towards the 3.7s but im still not sure
 

redcv6

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i can tell you i am in this same situation, except i don't know whether to go 3.45, 3.7 or 3.9. I'm looking at 3.7 as a nice happy medium, good luck mate
 

danja

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I have stock 3.7's, and no complaints here.

You really have to take into account your gearbox ratios too though, because its the overall ratio in each gear that really matters.
 

eaton v8

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and i love my 3.45s but im manuel
 

greenfoam

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For a 304

Standard cam and manifold = 3.45s
Aftermarket cam and manifold = 3.7s :)

In fact standard cam and manifold you may as well keep the 3.08s
 

betts

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I bought my car with 3.7's and then changed them to 3.45's. I can tell you I definately regret my decision.
 

v8_bomberdore

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true maybe 3.7s are the go then for the autos , ive drove a mates car that had 355 stroker with a solid cam and it has 3.9s i think , it had to much power off the line, u couldnt take off under power with out the tyres making noise and smoke, i know im not comparing apples with apples but it seems 3.9s are to steep specialy for the highway
 

danja

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For the record, my stock 3.7 is on a manual.
 

96SEN8R

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true maybe 3.7s are the go then for the autos , ive drove a mates car that had 355 stroker with a solid cam and it has 3.9s i think , it had to much power off the line, u couldnt take off under power with out the tyres making noise and smoke, i know im not comparing apples with apples but it seems 3.9s are to steep specialy for the highway
If you have a big cam, 3.9s are awesome because they get you into the power band of the cam quicker. You just gotta know how to drive them with street tyres. mashing the pedal off the line with that much power and 3.9s and it does turn into a nice smoke show. I reckon 3.7s for your rig. Even if it revs a bit higher on the highway, it wont use that much more fuel because your engine wont be working as hard to keep its motion.
 

v8_bomberdore

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If you have a big cam, 3.9s are awesome because they get you into the power band of the cam quicker. You just gotta know how to drive them with street tyres. mashing the pedal off the line with that much power and 3.9s and it does turn into a nice smoke show. I reckon 3.7s for your rig. Even if it revs a bit higher on the highway, it wont use that much more fuel because your engine wont be working as hard to keep its motion.
im having a turbo manifold made up so do u think 3.7s will be ok or would 3.45s be the go for a turbo setup
 
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