what stall converter should i get with my 4.56 posi rear end. in a 1967 camaro thats a daily driver. i wanna be running about 12 second aswell.

 

I do not know much about automatics, but the car you drive is a daily driver I would not go much over a 3000-3500rpm stall. And 3000-3500rpm stall is a bit big for daily street driving.

What gears does the car have now? Going to 4.56 you might not be able to run the intersate to well, it will turn mad rpms. Gas mileage will fall too.

I don't think the gear and the stall will get you into the 12s alone. Maybe you were planning on other mods as well.

 

yeah i plan on doing other mods as well. i just dont know what yet. if u have any suggestions id be very thankful to hear them. i am running a 3.23 rearend now. w\o posi. i know i can't go highway with the new one. but i got it for a great price. how much time do u think would drop from my 1\4 mile just doing the 4.56's, posi and a 2800 stall converter? thanks.

 

Your Welcome. And Good Luck Man.

You might want to wait for a guy to come on this thread that has an automatic and knows more than me about it.

What does your timeslip look light right now. 60ft times, 1/8 times and mph, and 1/4 times and mph? What kind of tires are you going to run at the track? With 4.56 and a stall you need some sticky maybe drag radial tires.

I would say you could pick up a half second with some good tires if not more. Now don't quote me on this. You need to wait for someone to come on that has an automatic.

 

i can't find my timeslip. i sorta remember tho.

60 ft. 2.23
1\4 14.96
mph . 93.5

i dont remeber 100 ft. or 8th mile.

 

Yea I think you could go mid to low 14s with the gear and stall. The 60ft is so important though. You have to have good tires.

 

right now i have Dunlop G\t Qualifiers.
275.60.15 once i heat em up they actually stick pretty good. i next to no wheel spin.

 

The biggest key is the 60ft times.

Generally every 1 tenth off your 60ft times, are about 2 tenths off your 1/4 mile time.

 

What tire size do you use. Running tiny 26" tall tires and 3.73 gears is like using 28" tall tire and 4.56 gears. Using 4.56 gears with 26" tall tires may overpower the tires very easily. It will also make the engine run at high rpms to run at highway speeds.

The 4.56 gears will let the engine work at a higher rpm. The stall speed of the converter should be matched with the gears but should also have a camshaft matched for that rpm. If the cam operates below 5500 and the converter stalls at 3500, the 4.56 gears will kill all the performance.

My car uses 4.56 gears and 29" tall tires. I shift at 6700 rpm and the converter stalls at 5500 (using a transbrake) and I only launch at 3500 rpm. It's only geared for 1/4 mile passes. At the end of the 1/4 mile I have no more rpm or gears left. Of course I'm maxed right out at close to 120 mph.

You don't pick a gear ratio to use just by choice. The engine and torque converter need to be matched to a specific rpm range. You then stuff the biggest (tallest) tire you can into the wheel wells and choose the gear ratio to use those tires with the engine/torque converter rpm range. You'll notice prostreet cars in magazine running 4.56 or 5.13 gears. You should also notice that they use 33" or 36" tall tires. That keeps the engine rpms down to a more streetable range.

 

my tires are about 28.5 inches tall. so what should i do? is that a good size for 4.56's or no? :S

 

What rpm does your engine shift at? The tire size looks good for those gears but you should have a red line range somwhere in the mid to high 6000's.

For street driving it "may" not be too bad with such a tall tire. My truck has 4.10 gears and 28" tall tires. With the OD tranny, 60 mph is around 2600 rpm. Cruising at 110 kph is just under 3000 rpm. Now that's with an OD tranny. Use a TH400 or TH350 and those rpms will be higher. Your 4.56 deeper gears and slightly taller tires will also have higher rpms.

A converter in the 4000-4500 stall range would probably work well for performance but will depend on what cam is in the engine. A converter with that much stall will build a LOT of heat driving on the street at low rpms since it has to slip so much below the stall speed. Keeping it more streetable would need a converter in the 3000-3500 range.

It's hard to build a vehicle that works best on the street and at the track. What you gain for one you'll lose for the other. You need to find a happy medium. If 4.56 gears and a high stall converter give you the best performance then fuel mileage and streetability will decrease.

 

You didn't mention anything about the motor and transmission in your car. I feel from your mph that you probably need a little more motor to make use of those gears. If the motor is in good shape a new cam, lifters, and valve springs might be in order. Once you build a little HP and match the converter to your cam you might want to buy a set of Cal-Tracs to help your sixty foot times. Oh, and buy some better tires, as tall as will fit.

Daren

 

i have a 350 small block. were puttin in a new cam and doing my heads pretty soon to get more power. gunna have about 430-460 horsepower im hoping. i have a th 350. i know my engine is weak right now thats why were doing it up. as for my tires. im not gunna fit any bigger tires than what i have in their. we already had to lift the rearend 3 inches and stifen the springs just so they don't rub. there 28.3 inches high. is a big tire and tall gears good? what will it help me with,