need advice please
Thread Starter
Racer
Joined: Dec 2003
Posts: 270
Likes: 0
From: owensboro ky
need advice please
i have a 69 with a 489ci motor that makes right at 600hp and right at 600 ft lbs. motor makes 500 ft lbs or more from 2500 rpm thru 6200. so my question is, its an auto with 308 gear. i also have a m20 4 speed and another rearend with 355 gear. wich tranny and rearend combo would you guys reccomend from what i have? also the stall conv. i have for the turbo 400 is 3500. i have not drove the car as of yet. its almost ready for paint. thanks for your thoughts. greg
Racer
Joined: Sep 2005
Posts: 359
Likes: 0
From: Shoemakersville Pa
Unless the car is strickly for racing I'd go with the m20 and 3:08 gears. I will be more fun to drive. The m20 has a lower 1st gear than the m21 or m22 so go with the higher rear. If your only racing I think the auto will work better.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
You'd better go with a "stout" clutch system with that engine [stock clutch is not strong enough]. I agree with the 4-spd.. If you use it as a driver most of the time, 3.08 gear is best; if you drag it a bunch, wide rear tires and the 3.55.
Thread Starter
Racer
Joined: Dec 2003
Posts: 270
Likes: 0
From: owensboro ky
it is a street car but needs to be pretty fast to hang with the crowd around here. will the 4 speed be strong enough?
car is for weekend crusing and such. has 335-30-18 on rear. im leaning towards the 4 speed but the gears im not sure about. i would think it would hook better with the 308, but pull better with the 355 or it might just blow the tires off with eaither gear but when it stops spinning wonder which would be better. thanks, greg
car is for weekend crusing and such. has 335-30-18 on rear. im leaning towards the 4 speed but the gears im not sure about. i would think it would hook better with the 308, but pull better with the 355 or it might just blow the tires off with eaither gear but when it stops spinning wonder which would be better. thanks, greg
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
if you want to hang with the fast crowd, then use the M20 and the 3:55, but keep in mind, using the first three gears will be riding a rocket, but once you're in 4th, the R's will drop dramatically.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
it is a street car but needs to be pretty fast to hang with the crowd around here. will the 4 speed be strong enough?
car is for weekend crusing and such. has 335-30-18 on rear. im leaning towards the 4 speed but the gears im not sure about. i would think it would hook better with the 308, but pull better with the 355 or it might just blow the tires off with eaither gear but when it stops spinning wonder which would be better. thanks, greg
car is for weekend crusing and such. has 335-30-18 on rear. im leaning towards the 4 speed but the gears im not sure about. i would think it would hook better with the 308, but pull better with the 355 or it might just blow the tires off with eaither gear but when it stops spinning wonder which would be better. thanks, greg
The automatic will shock the driveline less and hold up better. The TKO 600 and .82 OD with your 3.55 is the hot setup.
I don't think they should have ever built a Corvette with an automatic. Got to bang gears
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Thread Starter
Racer
Joined: Dec 2003
Posts: 270
Likes: 0
From: owensboro ky
both trannys are stock. i have to start with one or the other. then aquire a stronger one later. so it looks like i need to find a clutch and break pedal. anyone have one? to sell that is! i have been working on this thing since march. thought i would be done by now! i so much wanted to drive this car before winter.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
You don't [necessarily] need to tear the heck out of the 4-spd. You can't put all that HP down to the pavement at the start anyway. You should be able to 'feather' the clutch and throttle enough to keep the tires from lighting up...then throttle up! {If you put larger tires than that on, you might have some problems.}