need advice on the best 6 speed to hold up in a chevelle behind a 572 , any one running this engine zz 572 650 hp

need advice on the best 6 speed to hold up in a chevelle behind a 572 , any one running this engine zz 572 650 hp

How many options are there, Richmond makes a 6 speed and the T56 GM uses in the corvette, that would not be my first choice.

The reworked Viper 6-speed tranny that I wanna say is called "Godzilla" or some such hell-for-stout name.

It's supposed to be good to something like 1200hp????????????????

pdq67

I have the ZZ572 and have a TKO 600 behind it with a .68 OD and can only use it above 65 mph. At that speed the engine is at about 1,800 rpm and that is about as slow as it likes to turn with my 3.50 gears. I would never use 6th gear if I had it.

I have a bullet proof 6 speed for sale from my 71. It is a T56 with the best of everything. Even allows full power upshifts by just tapping the clutch pedal. Pretty sweet.

I have the ZZ572 and have a TKO 600 behind it with a .68 OD and can only use it above 65 mph. At that speed the engine is at about 1,800 rpm and that is about as slow as it likes to turn with my 3.50 gears. I would never use 6th gear if I had it.

The rectangular port heads on the 572/620 or the 572/720 do not help with lugging it down in the RPMs. Also, the intake and the camshaft powerband play a major role here too.

Jeff has a great baseline for you to compare, his final drive 3.50:1 x .68:1 is a 2.38:1 in 5th. If you choose a 5 or 6 speed with OD, keep your final drive where his is. If not, you will be downshifting a lot.

Jeff, What is the RPM band of the 572? Something like 2k to 6k?

Jody,

Exactly, anything under 2,000 is like riding a bull. It pulls very well above that and 6,500 is high as I take it on the other extreme. One other point, 5 gear is not on option unless I am on the highway. My 4th is 1 to 1 and great for around town driving.

Jody,

Exactly, anything under 2,000 is like riding a bull. It pulls very well above that and 6,500 is high as I take it on the other extreme. One other point, 5 gear is not on option unless I am on the highway. My 4th is 1 to 1 and great for around town driving.

I guess pulling down to 1000 rpm in fourth and pushing all the way to say 7000 without shifting is out of the question:D:D:D

My 390/427 with a solid cam, Offy dual plane manifold and a Holley 3 barrel would do this. M20 trans and a 4.56 out back.

This was back in the day when guys ran a little gear in there car, not all these wussy 3.55 and 3.08.:yes::yes:

Sorry, just could not pass this bye:):):)

I was talking to the GM Parts Performance people at Super Chevy/Maple Grove this weekend. They stated that the 572 will come alive at 3,500 RPM and is not user friendly with an overdrive transmission or a final drive operating below 2,000 - 2,500 RPM. He did state that some guys have installed the ZZ502/502 camshaft and some have also installed the ZZ502/502 camshaft and oval port heads on the 572. These change outs would allow for the low RPM lugging of an overdrive.

I asked them if there was any dyno info on the HP loss doing any of these change outs but, they didn't have any answers or figures. Maybe if you contact the GM Peformance Dept, they might have this dyno info?

I hope this helps.