[AdamIsAdam]

Originally Posted by TedRamAirII

Whatever 4 speed trans you choose isnt going to alter your highway speed/rpm. I have the same issue with my M21 and 3.31. I want a M22Z trans. That would get the first gear ratio at 9.86 which would be easy on the clutch. http://www.5speeds.com/cart/index.ph...&product_id=60

If I ever changed the tranny, I would want to go to an overdrive unit, not a 4spd if at all possible.

Originally Posted by highrisk

Adam,
Good to hear from you. I hope you are doing well. I think your car is prime for a 5 or 6 speed. My car is making about 476HP and around 573Ft/Lbs torque. That is what DeskTop Dyno estimates it at with a high flow intake. If you believe Edelbrock where they rate the RPM intake at max flow then those numbers would be 509HP and 574Ft/Lbs of torque. Either way the engine is very strong and close to your numbers. I ended up with the TKO-600 with the .64 OD from American Powertrain because you don't have to cut the floor. I got their White Lightening shifter which comes up at the stock location. Because of the offset I had to cut the top out of the shifter porch but that was easy. Then I only had to dent the floor in a couple of places so the transmission wouldn't touch the tunnel. If I did not mind cutting the floor and had the extra money I would have loved to go with the 6 speed close ratio with the .80 5th gear and the .62 6th to give an extra step before hitting OD. The only problem is 1st gear in the 6 speed is 2.66 versus 2.87 in the 5 speed. So you would loose some 1st gear grunt. But I am actually very happy with my combination and as I continue to work out problems and gremlins it is getting better.
Dale

Dale,
I'm well thanks, you?

I would think the TKO 5-speed with the .82 OD would suit my needs, no? 2.87 x 3.42 = 9.82 for 1st gear. Too much or is that ok?

With .82 and 3.42 and 26" tires that's 1,993RPM @ 55 (vs 2,650 today), and 2,356 RPM @ 65. MUCH better than I'm currently at.
FYI: at .64 OD that's 1,556 RPM @ 55 MPH and 1,839 @ 65.

Hmm, maybe the .64 would be better. I would LOVE to cruise at 1,800 RPM and actually get somewhere in a reasonable amount of time.


What 6spd fits our engines, they seem to be for LS motors?

Oh, and I don't mind hacking the poop out of my floor to make it fit. It's a clone and I have no center console to worry about. I just want a nice finished product that drives well and can handle the abuse.

[Smokmup]

I have 66 GTO with tko 6 speed, 27 1/2 rear tire, 390 gears. Have 5 thousand miles on car. Car runs and performs fantastic, wouldn't change a thing.

[highrisk]

Originally Posted by AdamIsAdam

If I ever changed the tranny, I would want to go to an overdrive unit, not a 4spd if at all possible.




Dale,
I'm well thanks, you?

I would think the TKO 5-speed with the .82 OD would suit my needs, no? 2.87 x 3.42 = 9.82 for 1st gear. Too much or is that ok?

With .82 and 3.42 and 26" tires that's 1,993RPM @ 55 (vs 2,650 today), and 2,356 RPM @ 65. MUCH better than I'm currently at.
FYI: at .64 OD that's 1,556 RPM @ 55 MPH and 1,839 @ 65.

Hmm, maybe the .64 would be better. I would LOVE to cruise at 1,800 RPM and actually get somewhere in a reasonable amount of time.


What 6spd fits our engines, they seem to be for LS motors?

Oh, and I don't mind hacking the poop out of my floor to make it fit. It's a clone and I have no center console to worry about. I just want a nice finished product that drives well and can handle the abuse.

I like the lower RPM cruise of the .64 OD. At 70 MPH I am turning right at 1900RPM with 26.7" tires. I guess it all depends on your engine but it sounds like it has plenty of torque. When I was looking at rear end ratios there are a lot of guys running the .82 overdrive and like it compared to the .64, I guess it all depends on what kind of driving you will be doing. If it is a lot of interstate the .64 will give a better cruise RPM. If it is a lot of 2 lane at 55MPH or less the ,82 would be a great choice. Check these guys out for transmissions and install kits http://americanpowertrain.com/ they are great to deal with and so far I am impressed with them. I did buy their Street Slayer clutch and did not like it for street driving and ended up replacing it with a McLeod twin disc street clutch, much nicer and it bolted right up to my stock flywheel.
We are doing fine and getting ready for Christmas,
Dale

[Formulajones]

Agree with Highrisk. I much rather prefer the .64. As expensive as these swaps can be for an overdrive, I want an OVERDRIVE. .82 just isn't much, I'm not paying $3,000 to $4,000 for just a 20-21% in rpm reduction. Rather just live with a 4 gear.

I'd recommend the .64 and get the most for your money.

As an example, I've run a couple of T-56 6-speeds. 5th was a .74 and even that wasn't really a big drop. 6th was .50 and loved it. Quite honestly I found 5th gear a waste and never really used it, skipped it most of the time driving. In my opinion the 6 gears aren't needed. GM could have made that a 5 speed and I'd have been happy. Now they are making the 6 speed with a .80 5th, that's even worse. I just need 4 forward gears and one overdrive.

[GTO TOM]

I am running 3.42 gears in my 66 GTO with a 461 Stroker that makes 450 HP & 500 Lb/Ft at the rear wheels. I cruise at 70 with 1950 rpm and 255X60-15 (27 inch)tires in the rear. I like the combo.

[TedRamAirII]

I just am thinking about dollars spent/ vs MPG gain. I may drive my car 500 miles in a year. So I think if you drove your car 10000 miles at 15 mpg @ 2.50 per gallon and now after spending maybe $4000 on a OD trans, now you get 20 mpg. Your fuel cost would be 1666.00 @ 15 mpg and 1250.00 @ 20 mpg. So thats $625 savings for every 10000 miles driven. So you would maybe have to drive 32000 miles just to break even....if you actually got the 5 mpg gasoline savings. I dont even know my actual MPG, I really dont want to know, and I dont care. So I would not consider it unless you have a cruiser and put more than 10000 miles per year. ; )

[The Champ]

Originally Posted by TedRamAirII

Whatever 4 speed trans you choose isnt going to alter your highway speed/rpm. I have the same issue with my M21 and 3.31. I want a M22Z trans. That would get the first gear ratio at 9.86 which would be easy on the clutch. http://www.5speeds.com/cart/index.ph...&product_id=60

Last year I swapped my 3.42's for 3.08 with my original M20 (2.56 1st gear) - so currently I have a 7.88 effective 1st gear (compared to 8.75 with the 3,42's). I'm most likely going to end up with an M22Z which will net me a 9.17 effective rate.

But It really isn't too bad right now as I'm so close the the original setup the car came with (3.23's which nets an 8.26) running 26.7" or 27.1" tires (recently switched to 17's) when I was running the 389, but now am running a 462.

With the current 26.7" tires at 70 I'm cruising at 2700 - much better than 3000.

And I can still run my original Hurst shifter and console...

[highrisk]

Originally Posted by TedRamAirII

I just am thinking about dollars spent/ vs MPG gain. I may drive my car 500 miles in a year. So I think if you drove your car 10000 miles at 15 mpg @ 2.50 per gallon and now after spending maybe $4000 on a OD trans, now you get 20 mpg. Your fuel cost would be 1666.00 @ 15 mpg and 1250.00 @ 20 mpg. So thats $625 savings for every 10000 miles driven. So you would maybe have to drive 32000 miles just to break even....if you actually got the 5 mpg gasoline savings. I dont even know my actual MPG, I really dont want to know, and I dont care. So I would not consider it unless you have a cruiser and put more than 10000 miles per year. ; )

For me MPG on a long trip was part of the decision, we are hoping to do a few cross country cruises with it. The other part, which is probably the biggest reason, is 1900RPM at 70MPH versus 3000 on an 8 to 10 hour a day cross country trip. Plus its cool to say I have a 5speed in my 65 GTO
Dale

[David Jones]

.64 and a 3:73 here. 455 with a 230/236 on a 110 cam

[highrisk]

Originally Posted by The Champ

And I can still run my original Hurst shifter and console...

I kind of cheated with the shifter. In December 2007 we had a house fire that destroyed my 66 GTO. For some reason I kept the shifter. I took the shifter apart and took out the shifter arm then cut and ground on it until it matched the attachment point on the 5 speed shifter and drilled two holes. I also use the stock 4 speed shifter ball so it really does look like I have an original Hurst shifter in the car. You have to excuse the Hurst shifter boot, the original 65 boot would not cover the 5 speed shifter.

Below is before and after of the 66. Very sad day.
Dale

[Formulajones]

Originally Posted by TedRamAirII

I just am thinking about dollars spent/ vs MPG gain. I may drive my car 500 miles in a year. So I think if you drove your car 10000 miles at 15 mpg @ 2.50 per gallon and now after spending maybe $4000 on a OD trans, now you get 20 mpg. Your fuel cost would be 1666.00 @ 15 mpg and 1250.00 @ 20 mpg. So thats $625 savings for every 10000 miles driven. So you would maybe have to drive 32000 miles just to break even....if you actually got the 5 mpg gasoline savings. I dont even know my actual MPG, I really dont want to know, and I dont care. So I would not consider it unless you have a cruiser and put more than 10000 miles per year. ; )

Yep, gotta plan to keep the car a long time if you drive it that little. On the other hand 10k a year on a classic is common for us.

[AdamIsAdam]

It's gotta be for the driving experience and comfort and not the MPG, IMO.

[Formulajones]

Originally Posted by highrisk

For me MPG on a long trip was part of the decision, we are hoping to do a few cross country cruises with it. The other part, which is probably the biggest reason, is 1900RPM at 70MPH versus 3000 on an 8 to 10 hour a day cross country trip. Plus its cool to say I have a 5speed in my 65 GTO
Dale

The other benefit, and I've done these cross country trips too, is that lower rpm cruising is so much quieter than buzzing 2800.
I don't concern myself too much with the MPG increases, mine do pretty darn good without an overdrive, but the engine working less, less wear and tear, less noise, is pretty nice.

I don't recommend OD's for some. I've done 3 swaps for a fella in 3 of his cars. I did the last one about 2 years ago. He doesn't drive any of them any further than 4 blocks to the local cruise. Really a waste of money in that instance, should have just left the 4 speeds in them.
Guys that really enjoy the cars, and I mean a "real" car guy that actually drives these things, the OD's are pretty sweet.

[Formulajones]

Originally Posted by AdamIsAdam

It's gotta be for the driving experience and comfort and not the MPG, IMO.

Yep. These cars can be pretty darn decent on fuel if tuned properly, and a combination that all works happy together. So MPG for us isn't the first thought when considering an OD.

[AdamIsAdam]

Originally Posted by Formulajones

The other benefit, and I've done these cross country trips too, is that lower rpm cruising is so much quieter than buzzing 2800.
I don't concern myself too much with the MPG increases, mine do pretty darn good without an overdrive, but the engine working less, less wear and tear, less noise, is pretty nice.

I don't recommend OD's for some. I've done 3 swaps for a fella in 3 of his cars. I did the last one about 2 years ago. He doesn't drive any of them any further than 4 blocks to the local cruise. Really a waste of money in that instance, should have just left the 4 speeds in them.
Guys that really enjoy the cars, and I mean a "real" car guy that actually drives these things, the OD's are pretty sweet.

x2 for sure! One of my regular cruises is 30 miles away very early Sunday mornings. It's about the furthest regular cruise I go to. I tend to drive 55 to keep the engine RPMs lower. I'm fine with that, but would much prefer to be doing 65 and 2200 RPM! Just not $5k worth.

[Formulajones]

Originally Posted by AdamIsAdam

x2 for sure! One of my regular cruises is 30 miles away very early Sunday mornings. It's about the furthest regular cruise I go to. I tend to drive 55 to keep the engine RPMs lower. I'm fine with that, but would much prefer to be doing 65 and 2200 RPM! Just not $5k worth.

You bring up another perfect example.

Here our speed limit is 75 mph. Most go much faster. Now myself, I'm happy going 65 mph, maybe 70. 65 mph in most of our cars is 2800-ish rpm (no overdrive) So not a big deal.
Our bigger cruise inns here are a 200 mile round trip for us to attend. I've been doing that for over 10 years, and there is no winter break here, we cruise year round. So in my case the cars could benefit from an OD. Can't afford to do them all, but may do one for myself one of these days.

I've done 4,000 mile cross country trips like this and I'm okay with it (65 mph at 2800 rpm)

[AdamIsAdam]

Yea, but when I'm doing 45 MPH, it's SOOO much more enjoyable inside to have a conversation and to not be worried about the higher RPM's.

[The Champ]

My favorite show is a 230 mile drive one way with a mix of Interstate and 2 lane roads. Dropping 300 RPM by doing the gear swap really made me feel a lot better on the Interstate sections. In cruising mode - I can pull about 18 MPG with the 462.

After I retire (Feb 2019), I may do an EFI conversion to help with driveability on longer distance cruises with varying altitudes. If it helps out the mileage a little, fine, but not that important to me.

[Formulajones]

If you liked a 300 rpm drop, you would really enjoy nearly a 1,000 rpm drop with a .64 overdrive.

[tom s]

With my 3.36s im about 1900-2000 right at 70.Will turn Waze on next time I drive it to be exact.Tom