4 speed with 3.07 gears ?

[fnoblitt]

blew up the 700r4 ,so i installed a muncie m20 wide ratio 4 speed. takes off great with the 3.73 rear gears. in fact i can start off in second gear from a dead stop with no problems. but i'm doing 3000 rpms going down the freeway. i have the orignial 3.07 gears, i was thinking of switching them to lower the freeway rpms down to about 2500.wich is where i do 90% of my driving. my question is how will the 3.07 gears be for taking off ? anyone have a similar combination?

[BCOWANWHEELS]

Can you say dog

[Longhorn Man]

if you can take off in second no problem, then the 3.07 gears will probably be fine for you. It won't be a face car, but I don't get the feeling that you think it is one now.

[tcb-1]

I have that combo in my truck from the factory. M20 and 3.07's. I've never seen 1st, I take off in 2nd sometimes 3rd, and 4th @ 3250 rpm is 75.

really not long haul freeway gears........

[samwise68]

I have a three speed with 3.07 gears, and take off is a bit doggy, but nothing too major. I'm not sure how first gear on the Saginaw 3 spd and a Muncie 4 spd compare, but it should be fairly close.

Regardless, if you're looking for freeway gears, you'll be golden. And take off may require a bit more clutch, but with a healthy engine, it should get up and go.

-Sam.

[fnoblitt]

it is a mild 350.my truck was a 3 speed /3.07 gears from the factory. i'm thinking the 3 speed 1st gear was around the 2.80 area. and the muncie i have is a 2.56 1st gear. so my only other choise for a 12 bolt rear is 3.42 ?

[airdale94]

The 3.07 will be fine for take off in 1st. And will put you at 2500 RPM at 65mph. The 3.23 will also run at at 2500RPM at 65mph.

[Boog]

Originally Posted by airdale94

The 3.07 will be fine for take off in 1st. And will put you at 2500 RPM at 65mph. The 3.23 will also run at at 2500RPM at 65mph.

I don't think so. You might want to figure that again.

[Mike C]

I'd keep the 3.73 and try and get a taller tire on it. Beg or borrow some rims and tires with a 30-31" tall tire and see how it drives. What size tires do you have now?

[special-K]

3.07s with a 4spd are fine with a V8.It`s not a hole shot gear,but it`s way better with a 4spd over a 3spd.To me,it`s like having 4.10 + o/d.I like grunt in my gears,but times are changin`.I`m planning 3.42s w/4spd because I really want to end up with a Gear Vendor o/d.In the mean time,or if it never happens,the gears won`t be too low and kinda high.I wouldn`t want 3.07 + o/d.

[Wrenchbender Ret]

We have a 60 panel with 3.08 rear end & a close ratio 4 speed. 350 stock engine. It works fine. Takes a little more clutch when starting out but is not objectionable. It probably wouldn't be good for heavy hauling or towing.

[killer71]

for what it's worth, once upon a time i ran 3.08 with a 350/turbo 350 and it helped with the exact problem your having. Killer wasn't a hot rod so i didn't really notice a lag in 1st gear. I even kept that particular gear ratio when i went fuel injected and it ran absolutely wonderful especially out on the hi-way! just my .02

[Mike C]

A close ratio Muncie M21 has a 2.20 first gear, which GM wouldn't sell with less than 3.73 gears. The 2.52 of the M20 is better, but IMO, the 3.07 aren't near enough. Just doing the math, the 3.06 first gear of the TH700 with 3.07 rear gives you a 9.39 overall first gear ratio, which is pretty good for getting out of the hole. The 3.07 with the 2.52 first of the 4 speed gives a 7.73, which is not so hot. If you have a stock cam and it will idle smoothly at 600 rpm, you might pull it off, but with anything in the 270-280 duration, you will need more gear. The 3.73 with the 2.52 first is, coincidentally, 9.39 or the same as the TH700 with the 3.07. Realistically, how much driving do you do on the highway? With 4.10 gears and 34" (measured) tires I turn approximately 2500 rpm at 65 mph.

[fnoblitt]

the 3.07 gears are in. and i'm very happy, it doesn't need to slip the clutch to get going. with 28" tires and stock cam i have pleanty of low end torque. and i like the fact i can wring out the motor a littlle more inbetween shifts.

[caminokid]

I am putting a 454 with a M21 Muncie and a 4:10 set up. I dont think there will be highway driving with this one. Pass everything but a gas station.

[ed2552]

Originally Posted by caminokid

I am putting a 454 with a M21 Muncie and a 4:10 set up. I dont think there will be highway driving with this one. Pass everything but a gas station.

You most definitely won't pass any gas stations!!!

Glad to hear you got the gears in, and are happy with them!