65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => Transmissions => Topic started by: dsags on July 15, 2009, 06:51:16 PM
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Three thousand RPM at 70 mph is getting a bit tiring. Taken two long trips totaling 1,400 miles and would really like to find a way to get those RPM's down. I've got a 4 speed manual transmission and I do not want to do any modifications to the the floor to make something fit.
Anybody have any ideas or experience in this conversion ? How about using a Gear Vendors overdrive unit ?
All info and ideas appreciated.
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WildBill Burton from the V8 site is currently installing a gear venders od. I'd holler at him and pick his brain.
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Thanks for the lead. Is WildBill what he goes by on the V8 site ?
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Yup. Wildbill.
You can also ask 'Larry70GS'. He has one on his automatic car. He always raves about it.
You could consider a Richmond 5 speed. They fit under the floor, but will need to enlarge the shifter opening.
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Walt, did a search on 'Wildbill' at the V8 site and came up empty. Am I doing something wrong ?
Do not want to enlarge the opening. No cutting, pounding, etc allowed. What 5 speed do you have in your car ?
How about the Tremec ? Several sites mention that the shifter position can be altered.
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Sorry, he goes by 'Topcat'.
This thread has some pics of his project:
http://www.v8buick.com/showthread.php?t=105846
I have the Richmond street 5 speed. Has a 1:1 5th gear and a 3.26:1 first gear, so it works well with rear-end gears in the 2.42 to 3.08 range. Used ones can be had for $1500 or thereabouts. New is $2000+
Richmond also has a new overdrive 5 speed. The case looks to be the same size, so maybe it will fit without floor mods. They're over $3k.
A Tremec will require major floor modifications...
The Gearvendors overdrive looks like a nice setup. Expensive, but nice!
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Thanks for the information. That is a great thread. Beautiful Wildcats. But did you see the hole he had to cut in the floor of a Wildcat to fit the O/D unit in ? Damn. I would think that his transmission hump is bigger than mine. But his is an automatic so maybe its different.
The Gearvendors website lists the unit as $2,795 for a T-10 like mine. That's pretty comparable to a new O/D Richmond or a Tremec.
Also have traded messages with 'racenu' on the V8 forum. He has a manual transmission in a 70's GS. Claims that both the Richmond and the Tremec require cutting to fit.
Things are not looking up at the present time. Could be time to call Gearvendors and listen to their story.
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I'm running a 200R4 behind my 455 with the stock rear gears. I can cruise at 70 while only turning 1600-1700 RPMs. If I drive normally, I'll get close to 20MPG on the highway.
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Walt, that is brilliant, as the Buicks have those highway gears more often than not.
How much torque can the Richmond handle do you think?
Ted
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Ted, Richmond 'conservatively' rates it at 450 ft lbs. Note that their T-10 4 speeds are rated at only 300-375 ft lbs.
http://www.richmondgear.com/07pdfs/RG20.pdf .....scroll down to the bottom.
I did read an explanation Richmonds were rated with 5000 rpm clutch-dumping drag racing in mind. Under street use, they will take much more. I bought one of mine from 'Brent' on V8Buick. He has one behind a turbocharged 455!
I wonder what the torque ratings are on the old BW T-10's and Muncie 4 speeds???
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Ted, Richmond 'conservatively' rates it at 450 ft lbs.
After re-reading it, they state "Capable of managing 450 ft. lbs. of torque at the rear wheels"
I wonder how that differs from the Buick 401 rating of 445 ft lbs torque??
I now have about 100 miles on my 401/5 speed combo. So far, so good! I only use 5th over 50 mph.
My GS's 2.93 rear/ 3.26 first is okay (9.55 overall) It's still a close-ratio trans, so expect to shift often. If you can afford it, a wide-ratio would work nice if you do a lot of Highway cruising at 70+ mph. I'll have more info after I get more miles on this beast. :icon_biggrin:
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:icon_biggrin: Shift often? hehe. I'm always skipping gears no matter what I drive...kinda goofy but in my old '03 Cobra 6-speed, I'd start in 2nd, then 4th then 6th...( slow driving, like in front of police station) maybe thats why I like 3-speeds!
With the Nailhead torque and broad power band mare gears are fun but not totally necessary IMHO. Not theat they are not fun! My Wildcat (vert) has the original gearset and I slip 1st ( ride the clutch) and skip 3rd pretty often. Thats why I've got the wider ratio in the 65 Skylark GS...for drivability and 1st gear ratio. My 3-speed Wildcat is great, although it could use an overdrive for the highway.
I wonder about the 450 rating...at the rear wheels would be different from at the flywheel and I have to think how that works. Does that get divided by the rear end ratio?