700R4 & 3.73s: too MUCH gear ratio???

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08-08-2003, 08:04 AM

#21

UKPaul

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Re: 700R4 & 3.73s: too MUCH gear ratio??? (Glensgages)

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But, I'm not gonna 'cut-it-up' (swap motor and/or transmission) in any way.....

Couldn't you swap the cam, raise compression, dual pipes, etc to get a bit more out of the motor? That's about what I did with my '81 & it pulls in OD when locked. Like you, I've got 2.87 on the back & I've got a 2004r so 1000rpm @ 40mph is what I also get. It pulls OK from about 50mph in OD. With a set of decent heads I've no doubt that I'll get a lot more go out of it.
:cheers:

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08-08-2003, 12:59 PM

#22

Glensgages

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Re: 700R4 & 3.73s: too MUCH gear ratio??? (UKPaul)

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Couldn't you swap the cam, raise compression, dual pipes, etc to get a bit more out of the motor?

Yeah, I 'could', if I stay with-in the parameters set by the 'primitive' (by current standards) and 'un-tunable' ECM. Members on The Cross-Fire Forum are very helpful, but even there, one member claims you can run 'such-n-such' cam, while another person says, 'Nope, it'll screw-up the ECM'. Members on that Forum are trying to incorpoate a 'tunable' ECM, but until then.....It's no wonder very few persons ever hot-rodded one of these things. One young guy in Texas goes 11.60's on nitrous, but I'm not aware of ANY Cross-Fires running 12s 'on the motor'

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08-08-2003, 02:50 PM

#23

ENCHANTMENT

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Re: 700R4 & 3.73s: too MUCH gear ratio??? (Glensgages)

Hi Glen,

I had a 700-R4 with 3.73 gears in my 406 SBC. I felt it was an ideal combination and would not have gone higher or lower with the ratio given it was a street driver. Since then I have gone to a stroker and T56 and the 3.73 seem a little too much.

Good Luck,

Ken,
Albuquerque

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08-08-2003, 02:55 PM

#24

Fevre

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Re: 700R4 & 3.73s: too MUCH gear ratio??? (CORKVETTE1)

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i said it before and i will say it again a lot of gear is just a crutch for lack of horsepower look at my 3:07 rear gear 700r4 does 1.50 60 ft and it will be in the 1.4s soon as we have better air in the fall :cheers:

Think you mean torque, that is what launches you. Bet you would get better times with a higher gear but loose some mph. Impressive times non the less.

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08-08-2003, 03:39 PM

#25

Glensgages

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Re: 700R4 & 3.73s: too MUCH gear ratio??? (ENCHANTMENT)

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I had a 700-R4 with 3.73 gears in my 406 SBC.....

WOW! :eek: 3.06 1st gear, 3.73 ring & pinion, AND the 'long-arm' 406 mouse? I doubt a good-running Cross-Fire (with-out N2O) will EVER make torque like a 406; maybe 3.73s ARE what I need... :thumbs: OK; now who here can get 350 HP out of a Cross-Fire (w/o N2O)? Don't be shy; step right up!!! :rolleyes: :crazy: :mad :lol: :banghead:

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07-21-2015, 10:49 AM

#26

78 old school

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Originally Posted by Glensgages

I know some members here have put 700R4s in their C3s. The 1st gear ratio in 700R4s is 3.06:1. My '82 Cross-Fire (no-laughing, pleeze!) has the 700R4, and 2.87:1 rear gears. The Cross-Fire needs ALL the help it can get, so, I'm considering swapping the 2.87s for 3.73s. My question is this: the 'effective' gear ratio in 1st will be 11.4:1 (3.06 x 3.73), deeper than my Z28 with custom gears in the THM400 (2.75:1) and 4.10 cogs (11.27:1). I'll eventually up-grade the Cross-Fire to 300-325 HP (where's CARTEK when you need 'em?

), and run BFG Drag Radials, but, WILL THIS THING HOOK-UP? Is it 'too-much' 1st gear? Other offereings are 3.31:1 and 3.55:1 ratios. Anybody with the 700R4 and 'gears', please respond. THANKS in advance.....