I have a 305TPI and with a stock paper air filter, 3" cat-back, and TB coolant bypass (I don't know if this has any effect..lol), I ran a 15.5@88 with my 2.73 posi rear and auto with a 2.25sec 60ft time.

I blew my differential to pieces today (1/5 or so of my pinion teeth are missing, and quite a few of my ring teeth are ground off), and I'm going to be upgrading to a 4th gen rear with either 3.23s or 3.42s and posi. Main reasoning is for the disc brakes.

Anyways, my question was...would swapping up to 3.23s or 3.42s make enough of a difference to get into the 14's? Also, which gear ratio should I try to go with? My LT1 intake and cam should be here in the next two weeks or so as well, and my car will like the upper RPMs quite a bit.

 

are you spinning for that 2.25sec? if so sus mods may be you ticket. either way going to a 3.42 will probobly only give you about 2-3 tenths. mabey 3-4 if your lucky. but the lt1 intake and cam is gonna be where your real gain will be, they should push you into the 14's on their own. get headers to, cams and headers love each other

 

Hell no.

 

oh yeah, (imo) 3.73 or 4.10 + some good tire will do you some good.

on my car going 2.73-3.73 only gave me like .2sec but when I put on DR's to deal with the spinning I went from 14.8 straight to 14.3 and 2.2 60'(like you) to 1.8

 

Interesting. That 2.25 was with no tirespin. That same day I ran two 2.3x times and they involved a little bit of spin. I was just curious as to how much of a difference the gears made. I've never driven a car before/after a gear swap. If I'm not going to notice much difference, I might be better off with the 2.73s for gas mileage, lol. The higher gear ratios would be better for a higher-revving car though, no?

 

also replace that stock filter man...........itll help alot.

 

I'm waiting for my LT1 intake and cam to arrive before I bother, but yes, I will be making a CAI like the 4th gen SLP kind with a K&N..

 

gears mainly help you on the holeshot. however a lower gearset will allow you to get into your powerband alot quicker. if you can get the rear like you are talking about you might as well becouse 3.42 is not that bad of a gear for mileage. you might actually get better mileage around town because it will take less torq to get the car going.

and if you have the tracktion consider a higher stall converter when you get the cash. converters will lower your milage but they do wonders for your 60' and 330'

 

456s bud would get you into the 13s that and a 26in tire would with susp mods and your engine mods of course gas mileage will go down but who cares youll be fast

 

4.56 gears will turn a 88mph high 15 second car into a 13 second car??? Will a K@N filter put it in the 12's?:lala: :lala:

 

there's a guy around me with those gears. its a camaro with a modded 350. he beats me out of the hole and it takes me a long time to catch up but if we run from a roll I'll annialate him every time

 

Yeah, I don't think I'll want 4.56 gears...and I don't see them putting me into the 13's either. I'd be spinning tires at 5-10% throttle.

We'll see which gears I get. Whatever 4th gen rear I can find around here (local) at a decent price, I'll take, and I'll go from there. I could just buy the gears for my current rear for like $190, but my whole rear is really rusted and I wouldn't mind having disc brakes, and if I can find one with low miles. I don't want to replace my ring and pinion to find that my posi fails a few thousand miles later...

My goal is to eventually get the car into the high 13's with the current motor, and 12's with the 355 I'm planning to drop into it. I think I can get 13's with home-ported LT1 intake, LT1 cam, K&N (duh!), headers w/ hiflow cat, home-ported heads, and chip-tuning. That will raise my powerband quite a bit as well. Give my buddy's '97 Z28 a run for his money

 

first of all you wont spin wiht 456s if you have great tires and some susp mods. and i dont see why it wouldnt shave off a second or two.

 

(imo) even if you could get great hook with a 4.56 (which many people do) if you don't have the top end HP and high RPM to back it up you will be left very vulnurable at high speeds. especially on the street.

 

but on teh street its only till 60 and you should be able to get that fast. besides gives you another reason to build a better motor

 

I think I'll be happy with 3.42s for a while. By the end of this summer, I'm hoping to have 275ish HP (not at the wheels though, at the crank), and it'll be all top-end. The LT1 intake and cam will be able to pull all the way to 6k, especially with ported heads. I may not bother with the porting until winter though when I have a second car to drive. I may lose some torque with that intake/cam setup, but the 3.42s will still make it feel "torquey" and should give me enough low-end to still be fun on the streets, yet have the high-end for track and highway, even with the 3.42 gears.

 

I dont see it taking a second off as the TPI cars arent known for their high RPM steam... There is a point where too much gear hurts you, and I think 4.56s would do it in a TPI car. I know when they tested a Mustang a while back, it saw good times with 4.30s and anything more it fell on its face!

 

Well, I will have the LT1 setup which is much more free-flowing at higher RPMs. But 4.56 gears would drop my 18MPG (around town) to like 10-11MPG, and I can't have that seeing as my girlfriend lives 1/2 hour away (about the same as school too and not really "highway" driving). The 3.42s will still bring me down to 14MPG or so, but I can live with that I guess.

Maybe I'll get pulleys to give me a tad bit of gas mileage back and quicker revving Also, the AIR will come out when the headers/cat get put on, and the A/C is already gone (compressor will be gone soon enough), and I'm considering an electric water pump and removing power steering for a manual gearbox. Race car!

 

umm 342s wont make you feel torquey unless your down to 273s or lower. also an lt1 intake on a 305 is still a 305 and electric water pumps are like race only pulleys really dont do jack just my
jon

 

Actually I haven't even considered the electric water pump. Was just saying stuff taht should improve my gas mileage, lol

I do have 2.73s....well, had, before I blew them up. I'm sure going to 3.42s from 2.73s will be quite noticeable. Everyone else that's done it seems to have had only good things to say about it (except of course the gas mileage )

All I was saying about the LT1 intake is that its going to allow me to rev higher and will raise the powerband. I didn't compare my car to a 350. I'm just saying that the shorter gears (3.42 vs. 2.73) will like the higher RPMs more..

 

hell yeah i went from 2:73 to 3:73 and the car feels totally different it definatly alot faster too now if i could just get the speedo to work right i'd be set

 

itll be noticeable but ur gas mileage wont suffer that greatly i know a guy with 411s 10:1 compression the works in a 62 nova and gets 7 miles i get 8 in the elco but with the 355s he had earlier he was only getting 10 so obviously it wont hurt u that much to go a little steeper i would guess if u went to 373s ud be a 15 mpg

 

That's a 30% reduction in mileage. Doing the simple calculator math...

2.73s...18mpg (same gear)
3.23s...15mpg (15% loss)
3.42s...14mpg (20% loss)
3.73s...13mpg (27% loss)
4.11s...12mpg (33% loss)
4.56s...11mpg (40% loss)

That's just going "(x / y) * m = n" where..
x = current gear ratio
y = new gear ratio
m = current gas mileage
n = new gas mileage

 

I went from a 2.73 gear (15.6 @ 85) to a 3.23 gear (14.9 @ 92) There was a major increase in power. Itll spin the tires until i let off now. I also did a shift kit at the same time. All of this was done with my TBI car.

 

Now, that's what I'm talkin about. Actually someone just emailed me saying they have a rear off an '00 Camaro with 3.73 gears in it

I'm going to eventually get around to a shift kit. That's pretty easy, no? Just drop the pan drain the fluid unbolt the valve body, and replace it with the new valve body, or do the kits make you actually mod your own valve body? Either way, doesn't matter to me, I just want to know what to expect.

 

a shift kit does not replace the valve body, you ger a few parts to modify the valve body, modivacations for the pressure valves and the accumulators. or at least thats whats in a B&M kit.

unless you have done it a few time I highly suggest you have someone that has done it a few times watch over your shoulder. the first time I did one I put the pressure valve in backwards and I blew the trans. however since then I have done several succesful shift kit installations.

*btw most will flame me for this but a shift kit will not really make you that much faster, mainly it makes your trans a little stronger

 

Where do you live around here? I'm from Bloomingdale (about 1/2 hour NW of Chicago). I've been considering a kit from TransGo for a while. They tend to be fairly cheap on eBay.

 

im about 2 1/2 hours west from chi town. I have the B&M kit. It has parts to upgrade your valvebody in it. The shift kit DOES NOT make your car any faster. I dropped the pan and followed the instructions. Its not hard just time consuming. I also installed the corvette servo when i did mine. If you Firmer shifts just go with the vette servo. It is well worth the $19 shipped.

 

Well, I would've thought it would make the car a tiny bit quicker in the 1/4, but even then I don't really care. I don't want my trans slipping, and I like the feel of hard shifts I'll probably just go with a $36 shift kit off eBay, that separator plate (if there's any advantage, its only $16), and the vette servo sounds good too. I have a post in the drivetrain board about that now though.

 

want hard shifts do what i did get a manual valvebody with a trans brake

 

good thought, however I think he is looking for somethin a little more streetable and on a much smaller budget

 

Put a stick in it, and get those hard shifts, as well as more streetable and better gas mileage!

 

Nah, that's okay. I did want a 5spd..but I figured it was next to impossible to get a 5spd/V8/T-top car, so I settled for V8/t-tops. Also, my buddy in a '97 Z28 M6 car was running 2.4x 60' times and I was running consisten 2.3x times with one 2.25. Granted, his times would be much better with a better driver...but he's had a lot more experience than me with a stick. By the 330' though he was murdering me

 

my car is for sale it has a 5 spd t tops and its a l69. passes smog too

 

Well, I'm not looking for a car right now. And if I was, you're 1500+ miles away.

Anyways, I'm not looking to buy a manual valve body, and I don't quite understand the concept of a trans brake. A bit too pricey there when I can just get a shift kit for $65

 

with a trans brake basically you get an electric servo in the valve body that causes the trans to disengage gear when the button is down

you rev up your motor at the tree and when the light tuns green you just release the button and hold down the go fast peddal

allowing you to rev to an RPM that is higher than your converters stall speed enables you to get a higher stall out of the tc when the button is disengaged. this also drastically improves your consistancy and r/t when used correctly


btw, your buddy with the 94' Z must not know how to launch if he is only pullin 2.4 60's. even for a stick that is slow

 

Ah, thanks for the info. Yeah, it was the first time at the track for both of us that day. He ran a 14.4@96 I think with 2.4x 60'

 

14.4 is about right for a semi stock 94 Z. He must be missing traction.

 

i dont think that shift kit is gonnabe the magic answer ur looking for. if u wanna go fast you gotta have money they go hand in hand

 

Maybe if your car runs 15s or 16's. My firebird gets to 60 so fast its pointless to only race to 60 because I haven't even hooked the tires up by that speed. I'd say a more average street race speed on a "safe" road is 85-95. Its kinda dumb to setup a car to only race to half its 1/4 mile speed. Kinda like premature ejac......well you get my point.

 

i only race till 60 because thats a still sane on the street. stop light to stoplight is the usually won and lost by the first 100 ft or so. i can hook and my car dips into the 12s so.................. and 85 on the street is just asking for trouble what do you do if u hit a curb that fast. it be like hitting it a 60 cept alot worse.
jon