camaro86

which gears should i go with on my stock Lg4 except for exhaust and k&N filter? its my daily driver. im going to go with a carb 350 later down the road. im thinking about going with 3.73 open because im going with carb 350. and 3.42 open cause of gas mileage.

91ChevyRS

well, down the road I plan on going with the 3.42 gears, the reason why I am holding off now is because my current gears are still going strong and they haven't given me any problems....but eventually its gonna go and then I'll have an excuse to buy those 3.42s....

I am not looking for anything extreme, but I heard the 3.73 gears would wear down your tires faster, and you'd be chirping in almost every gear....with the 3.42s you will get the chirps where it matters most.

The cost difference isnt that great with 3.42s and 3.73s but ultimately I think the 3.42s are better.

bitchin85camaro

3.73's are fuuunn. ive got 4.10's, and they are a blast. gas mileage dosent change too much unless your on the thruway alot. but just driving around town, your gas mileage wont change. IMO its worth it. i went from an open diff 3.42, then to a 4.10 posi, and it felt like a different car after everything was said and done. oh and by the way, my car is a daily driver also (i drive 30 mins, each way, downtown 6 days a week to work construction. with a th350 with 4.10's and i still wouldnt have it any other way)

camaro86

will 3.73 work good with the LG4 ? do 3.73 still have a good top speed cause im thinking about doing some road racing?

sofakingdom

iTrader: (1)

That's a WHOLE LOT DIFFERENT from a 700 and high-numbered gears....

One of my little brothers had a LG4/700/3.73 combo. It was beyond gutless on the highway. Had a nice 0-15 mph; it was completely done once it got that far.

I think 3.42 is about optimum for the stock LG4/700 combo. You gotta uncork the motor to where it can prduce meaningful power at RPMs above 3500 in order to go any farther.

There's no sense at all in spending money, and not getting posi. It won't affect your gas mileage.

1meanGTA

well i just fragged my richmond 4.10s, had a set of precision 3.73's put in, got the car back today, and MAN what a difference. i didnt like the 1st gear at all on the 4.10s, way too short. i couldnt floor it at all in 1st without getting major wheelspin, and had to shift to 2nd at like 10 or 15. on the highway, it was high enough in its powerband that the tpi intake started running out of steam. a freakin stock wrx sti took me on the interstate.

now, its more streetable in town, since 1st and 2nd are so much longer. i can be cruising at 25 in 2nd, floor it and the car will go sideways and MOB OUT. theres no doubt in my mind it'll run a quicker 1/4, especially with the spray. on the interstate, it definitely has more ***** now. much more responsive, and better gas mileage and top speed to boot.

lesson - dont get more gear than you need. the guy that had the car before me had a miniram on it, and put the tpi back on to sell it to me. it hauled *** with that miniram, and the 4.10s were a good combo for em.
4.10 + tpi = tire spinning, gas eating mobile. i wouldnt be surprised if it was even a bit quicker with 3.42's and the tpi, but i play on getting a holley stealth ram before too long, and i thought the 3.73's would be just perfect for that, and work well with the tpi.

camaro86

so what gears do you recommand for the LG4?

1meanGTA

i'd probably do 3.42's, but i've never had an lg4, dont take my word for it. if that the tbi 305?

camaro86

3.42 will be alright for road racing?

1meanGTA

would be great, but i would get more opinions than mine before committing.

6SpeedTA95

TBI 305 replaced the LG4 I thought. The TBI motor is an LO3 if I remember right. The 3.42's is what I'd go with, it offers reasonably quick response, still driveable in the winter and will keep you in the power band with just about any motor.

L98IROCZ89

What are you planning to achieve?

A little more go without hurting gas mileage too bad? 3.42

A lot more go and hurting gas mileage by a noticeable amount? 3.73

Trying to get your car to run the best 1/4 time? Match the gears to the trans gears, tire size, etc so that you will cross the line at the right RPM. Just throwing the bigger gear in is not always the best choice and can actually hurt.

Many people, especially TPI are so quick to throw 3.73 in there and then are disapointed because when they go to cross the line at the track they in between on the gears/rpm. That is to say that they need to choose between overrevving the motor a little bit in 3rd or 4th (depending) or shifting to 4th or 5th (depending) it's useless for one of two reasons: either they shift and by the time they engage that next gear they are done and they were esentially in neutral for the very last portion of the track, or they shift into that 5th gear, and have it engaged for the end, but that's not good either.... would you really want to be in an overdrive gear at the track?

Just some things to think about.

camaro86

im not going to drag race much im aiming towards road racing. I dont relly care much about gas milage unless it hurts it too much.

91blkta

3.42's would work the best for your 305 you still have a lower rpm on the freeway. You have to keep a higher rev on the highway with 3.73 which puts much more strain on a stock 305 and burns more gas. If your motors near stock 3.42 will make you happy in the long run.

camaro86

what about 3.23's is their a big difference in gas milage, top end speed then 3.42?

6SpeedTA95

That really depends on your vehicle and how it builds power. 3.42's are a good all around gear. You've got some good low end grunt and you dont wind out of your powerband too quickly. 3.23's also aren't a bad gear for TPI cars. Is this a 5 speed or auto car?

camaro86

its a auto.and about how much top end speed and gas milage will i lose if i go with 3.42 over 3.23?

6SpeedTA95

You wont see much of a difference between 3.23 and 3.42. On a stock vehicle you'll see about 1 or 2 mpg on the hwy and less than that in the city.

camaro86

which will be best for street and road racing 3.23, or 3.42?

6SpeedTA95

I really think on 3rd gens or auto 4th gens 3.42s are the best all around gear. 3.73's are good with the 6 speed 4th gens or 6 speed 3rd gens. Otherwise 3.42 is the way to go.

camaro86

thanks all of you helped me alot im sure im going to go with 3.42.does anyone know how i can find slp posi on their website? do they sell it seperated?

irocbarry

the top speed shouldnt change much with any of the gears, the odds are you arent gonna redline in OD with any of them
i cant in my L69 t5 car with 3.73

as for better mpg not sure what difference itll make, with my stock setup i pull 23-25 on the highway at 70-80 mph with the rpms around 2500 or so

i personally woud go 3.73, unless your car redlines with them in OD, if it doesnt then itll just get you to top speed a little quicker


someone correct me if im wrong but as long as your not redlining in OD the top speed will essentialy be the same for you car, just running different rpm's with different gears

91blkta

If your close to redline in od then you are burning a ton of gas that not good if you want the best of both worlds which is good gas mileage and quick acceleration. Even though your not at redline in od you are still putting more wear and tear on motor at 3500 rpm on freeway then if you where at 2000 rpm. The more rpm you pull for long periods of time the more wear and shorter the motor life.

irocbarry

didnt really mean run it near redline for highway cruising
he said he wanted to do road racing a bit, if your racing you want best performance, not mpg, or atleast in my opinion

91blkta

That makes more sence then

6SpeedTA95

Not always it depends on how the vehicle builds power, in the case of a TPI car with the major power fall off in the upper 4000 area switching gears could indeed lower your top speed even if you're not at redline. A stock TPI car wont make enough power to pull at redline in OD.
In my Trans Am my top speed remained the same, but now I'm close to redline at 165mph. Before I was about 400rpm below redline, but I dont have much powerfall off at all above 5500rpm.
Really it all depends on the motor.
Take a high revving motor that doesn't build much power till 5000+ and peaks at 6500rpm...lets say top speed in 6th gear with 3.42 gears is 165mph and you're turning 5100 rpm. Lets say you switch to 4.11 gears, now your going to be turning 6130 rpm at the same 165mph but you're going to be in a sweeter spot of the powerband, making more power and as a result you'll keep pulling at 165 mph slowly bringing the motor closer and closer to peak power. You may see a 7, 8 or even 10mph increase in top speed depending on how the power curve is for the motor. Realistically with a typical power curve you'd stack on 5mph or so. The opposite can happen if you get a car out of its powerband with gearing.

1meanGTA

jesus, you've taken your car to 165? what mods do you have? i dont really know how fast my car is, the speedo goes up to 145 but it isnt calibrated for the gears. i'd guess it tops out around 135-140. i know you've got 2 more gears but still... damn...

camaro86

remeber im going to get a 350 sooner or later the 350 will aleast be pullling 380HP.

hoogabooga

iTrader: (1)

i have a bowtie od. 700r4 with 3.73 gears. it gets 18-19 mpg with no highway driving.

6SpeedTA95

I've had to to 163mph before I really started modding it...after the mods I pegged it in 5th and it did pull slightly faster. I have 3.73 gears, CAI, catback exhaust when I did the last top speed run. I've added a new computer tune since.

It helps when you have buddies that are cops

edit: My speedo ends at 155, but where the peg is its about 165...on the 163 run I had it clocked on the other run I had to plug the numbers into a calculator because my speedo was off due to the gear change and at that point I didn't have computer reprogrammed. I just noted my rpm and plugged it in when I got home, it came out to 166mph...

86IROCTHD

in my iroc i did 155 in it one night on the highway... my trans am tops out at about 140ish.... its an auto with 3.73's and to who ever posted that a 700r4 with 3.73's is gutless on the highway i dont know what they are talkin about... mind u i dont have a stock motor by any means.... but there are alot of c5 vettes that cant keep up on the highway till i top out of 3rd at WOT... and my 98 ls1 m6 z28 has 4.10's and i have done 165 in it.... if u are gonna put in a bigger motor go with the 3.73's they will help out more... and it will only wear your tires depending on how heavy your foot is....and i am heavy... and my fuzions still have 7/32's left and i was in a burnout contest with them

GOTMYZ

iTrader: (1)

I would use 3.73. I hear a 4.10 is ok as long as you do not drive on the highway. Gas mileage gets in the single digits.

1meanGTA

i honestly didnt even like my 4.10s around town. 1st gear in the 700r4 is way too short with such a steep gear. even with my 3.73's its still too short, im wishing i'd have gone with 3.42's now.

but yeah, its definitely not gutless on the highway. that 4-3 downshift will plant you in the seat, especially on spray.