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#41
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Ahh ok, I was aware of the change. The 80e I have is an earlier design. What are you guys doing for a rebuild for say, 600 / 600? I'd live to get away from the adapter plate but the replacement ultra-bell is expensive. If you run a 3.08 gear with t400 it is the same as a 4.10 with an 80e in overdrive. |
#42
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LOL yeah I'm not putting a 3.08 gear in it. Not only is that a carrier change, That would absolutely kill the 60, likely push the converter out of it's usable range and another converter would be needed, and would slow the car down to the point I'd be digging into the trans for a low gear set (which still wouldn't get effective ratios where I am now) to try and gain back some of the ET I'm currently running. I'd much rather go the 80E route, keep the 4.10 setup that really works well with the RPM range this engine likes to cross the finish line at, and then enjoy the .75 reduction and gain 20 mph on the highway. It's a win win, best of both scenario, but it costs money of course. Maybe at some point if I stop racing the car so much I may drop the rear gear down to a thin 3.73 that works with the Moroso Brute Strength 4 series carrier, but I'm not going to be in a hurry to do that. I'm likely going to go with Hughes "street/strip" 4L80E rated at 850hp and give me room to grow for the new engine setup, plus they are local to me. Last edited by Formulajones; 07-05-2020 at 11:11 AM. |
#43
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I went with Gearstar because they're within driving distance for me. Akron, Ohio. https://gearstar.com/gm-4l80e-perfor...ssion-level-2/
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'04 GTO Yellow Jacket, A4, Kooks, CAI, etc. '02 Firebird, V6, auto '68 GTO Convertible, HO, 4spd, driver '66 LeMans Hardtop, 400, FI, A/C, 4L80E. '64 GTO Hardtop, "389", Tri-power, 5 speed, A/C, Yorktown Blue. http://www.gtoaco.com |
#44
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I probably would have done the same if I still lived in Ohio. Location is a big player in choice for me.
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#45
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final drive ratio can also bring up some other considerations. Friend of mine with 462" olds in an 87 cutlass with 6 speed manual (5 is .75:1 and 6th is .5:1), 9" ford rear. He autocrosses occasionally, and drives it city/highway/whatever. He's got 4.30s in the back and in 6th its up to 2.15:1! Problem he had to deal with is driveshaft diameter. With that 4.30 gear at 80-85mph, you have some sustained high driveshaft rpm. He had a vibration that stemmed from insufficient driveshaft diameter for the rpm it was running. The engine is just purring along, but that driveshaft is spinning like the knob on the ****house door.
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Clutch Guys Matter _______________________________________ 53 Studebaker, 400P/th400/9" 64 F-85 72 4-4-2 Mondello's VO Twister II 84 Hurst/Olds #2449 87 Cutlass Salon 54 Olds 88 sedan |
#46
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Agree, driveshafts should be considered. I ran a couple of 6 speeds for a while, with .50 overdrives and 4.10's.
In all the overdrive swaps I've done I always had a new (stronger) shaft professionally built and balanced, usually with larger joints in the process. I generally end up with thicker wall tubing and stick with steel if the length isn't excessive. Once they get to a certain length, whipping becomes a problem because of the weight, and why GM went to aluminum drive shafts. You see that in trucks a lot, where GM used to use a 2 piece steel shaft with a carrier bearing in the middle for support because they had to be so long. When that idea was eliminated they went to one piece aluminum shafts to keep the weight down, then the shafts could be made much longer. Always something to think about. |
#47
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There is also a lot more heat generated in the rearend with the low ratios. The heat problem with 3.90's and lower wasn't much of a factor with the old Muncie because we worried about what the extended term RPM was doing to the engine. While we might have bumped speed up for a few miles with the lower gearsets, we didn't get on the freeway and go for an hour or more at high speed. We tend to forget that that little pinion is madly spinning away since the engine now loafs along in overdrive.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#48
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Another reason the extra capacity aluminum covers are a good idea.
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#49
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Ford style 9 inches used in nascar have fluid coolers and pumps, because of the sustained time they are used, (roughly 3 hours) even though the ratios are mostly 3.50 and numerically lower, they still build heat running in a high heat environment, exhaust proximity, and black asphalt that routinely can be in excess of 140 degrees. |
#50
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And trucks usually have larger diameter tires which reduces axle speed.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#51
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3.55 or 3.42
I had a 700R4 on my 65 Goat and with that annoyingly low first gear of 3.06, it was super revy around town with 3.73 - I dropped down to 3.55 and about right, especially with big tires.
if you have more stock tires, I'd say 3.42 is perfect. Just my experience. Remember that 3.06 is made to get a heavy truck or SUV rolling from a dead stop, gets a little annoying in a GTO for driving in stop and go traffic, and you can't start off in 2d.
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1974 Lemans Sportecoupe GT (daily driver) .030 over 354, #47 heads (84cc), Lunati voodoo 700 camshaft (207/213 @ .050), logs, 2.5 duals, X-pipe and Dynomax super turbo mufflers, 3.08 rear |
#52
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Jeff |
#53
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Question SJdiesel, Since lugging at 60 is your concern, can't you adjust the lockup with the controller you are using?
All the "E" transmissions I've messed with you could program the lockup to engage or release at any speed desired, and even play with TPS input so at 60 MPH if you pushed the throttle passed a given percentage, the converter unlocks so you don't have that chug or lugging sensation. That is the beauty of having an electronic trans. Even with an aggressive camshaft you can delay the lockup anywhere you like for smoother operation at low speeds or have it pop out with more TPS input. Something that is nearly impossible to do and work well with TV cable OD's and lockup converters that work off a vacuum switch. Very limited with what you can do with those. Just curious, what controller are you using? Does it not have that kind of adjustability? |
#54
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What flexplate is used with the 4L80e? Can a flexplate for a T400 can be used? Do most converters have a three or four point mount? I gather the converters are different between the 4L80e and T400?
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#55
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Some even have a 6 bolt mount. I just installed a real 69 GM L88 converter in a 400 here and it's a 6 bolt flexplate mount. The flexplate only had 3 of the 6 holes, so I only used the 3. Could have drilled the other 3 just wasn't ambitious enough.
The last 4L80E I had here had a GM converter in it and it was a 6 bolt. |
#56
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I guess I should clarify the "lug" I was talking about earlier. Its not really a bad lug, the engine makes plenty of low end torque to pull it. And yes when traffic slows down I sometimes drop to third, but I have since played with the controller and it now unlocks the converter which seems like the engine is happier.
I guess I just figured why have such tall gears with an OD trans. Maybe I'm overthinking it. I'm running the USShift controller. Thing is awesome! Well worth the $$$. Mick, I am running a regular flex plate I purchased from Butler. Same one I ran with my th400. My 4L80e converter has 6 bolts but the flex plate only lines up with 3. So I have three installed. like I said earlier, I am going to leave the 3.23 gears for now. I want to swap out the converter first for something more "sporty" .
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Sean 1967 GTO Koerner built 468 with Edelbrock RP’s 315cfm by Butler, Luanti Voodoo HR 20510713, 4l80e, Holley Terminator EFI |
#57
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#58
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This doesn't have a whole lot of relevance, but does have a little. My 67 "Cruiser" had a Chevy 3.31 rear for many years with the 200-4R. When I was getting ready to put it up for sale I figured it was time to rebuild the stored 10-bolt so the car would be a little more correct. As long as I was at it, I changed the gears out to 3.55's. Not much of a change, but after so long driving it with the slightly higher ratio I found myself cruising five MPH slower with the 3.55's if I didn't watch the speedo. Funny how we get used to a specific engine sound/vibration. I just mention this because if you live with the 3.23's for very long, a change to a lower rear gear might seem a little unnatural buzzing down the freeway.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#59
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Under what conditions does it unlock? |
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