Glide Vs turbo 400

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prairiehotrodder
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Glide Vs turbo 400

Post by prairiehotrodder » Sun Mar 13, 2016 11:13 pm

Which is gonna be quicker? Car is an 81 malibu, 3200 pounds with driver, 4.10 gears, 540 BBC with around 700 engine hp , no nitrous, 29.5 x 9 ET drags, ATI 5200 stall 8 inch convertor.
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Re: Glide Vs turbo 400

Post by Speedbump » Mon Mar 14, 2016 10:32 am

I'll make a WAG here and say with that gear, the 2.40 low gear of the 400 will be quicker if the tires hold the launch. Question is whether it will beat the 100 pound weight penalty. I'd say the glide wants a 4.30 to 4.50 gear but then you need to figure what your trap rpm needs to be.
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Re: Glide Vs turbo 400

Post by Greenlight » Wed Mar 16, 2016 6:59 pm

In a drag race only application, I have never seen a stock TH400 (no ultra-light parts) run quicker than a stock based Powerglide. When NHRA allowed Stock eliminator cars to run any "GM" transmission, most of the high HP cars that came from the factory with TH400 switched to either P.G. or TH200 transmissions. They ALL picked up a lot of ET. I suspect 0.15 seconds was typical.
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Re: Glide Vs turbo 400

Post by Coloradoracer » Sun Mar 20, 2016 10:02 am

The weight of the car will have a significant effect on the performance, and the converter will be critical. With your weight at 3200, the TH400 should be the better choice. A glide will be VERY converter sensitive, and even with that it will typically be a little slower off the line than the th400, but both should et and mph about the same. In that case, my preference is the th400.

You'll hear a lot of hype about how the 400 takes "x" amount of hp to drive compared to the glide. In actuality, the hp it takes depends on the rate at which the internals are accelerated, and the hp required to drive either the glide or the 400 is not a set number. I've seen people buy into the "glide is faster because it takes less hp to drive" deal before, pull out a 400 and install a glide, only to find out they run the same et at the end of the track.

Also, there is not a 100 lb difference in weight between the two. It's about a 30 lb difference and its not going to affect the car as much as you'd think. But here's the thing to consider: A basically stock th400, properly assembled, will last for years and hundreds of passes behind what you described. No special parts needed, although an aluminum direct drum is always a good idea, but it's not needed. A stock power glide however is a different story. If it's a 1.86 gearset, you're going to have to buy a new one. Those won't hold any amount of hp worth mentioning and it's wise not to test that theory. The 1.76 gearset is a much better choice, IF you can find one....if not, you're looking at a minimum of about $800 for a new gearset. The high drum piston will need to be machined for more clutches, as will the reverse piston, and you'll need an aftermarket dual ring servo. The valve body is a wash on either trans, as a good t-brake style is about the same on both. The stock input shaft will have to be replaced unless you like breaking them. A decent one is only about $100, but that's still adding to the cost. IF the pump is in good condition, there are mods you'll have to do to it for it to live, but a better choice again here is an aftermarket one, or a stock one that's been professionally prepped. Lastly is the case. If it's an OEM case, you're dealing with a 40+ year old case that may be questionable. While there are many still in service today, finding a good used one is getting harder and harder. Sometimes its better to try and find an SFI case that's out of date someone might be selling. You're also going to have to make some mods to the case as well.

I also mentioned with the th400 the converter choice isn't as critical as it is with a glide. They are much more forgiving in that area. If the converter for the glide setup isn't dead on, you're leaving et on the table. A reputable builder can spec you one, but most are going to be in the $700-1200 range depending on what you get.

Just some food for thought.
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Re: Glide Vs turbo 400

Post by John Wallace » Mon Mar 21, 2016 10:05 am

Mark, are you running a PG in the dragster?

:?:
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Re: Glide Vs turbo 400

Post by prairiehotrodder » Mon Mar 21, 2016 10:40 am

Thanks for the advice. I've been running a turbo 350 for the last 4 years and with street racing traction has been a disaster. Thats why i went to a glide. I have a stock 1.76 gearset, stock case, dual ring servo, BTE trans brake valvebody, ATI input shaft and extra clutches. I'll give the glide a try and see how it goes. I hear what you are saying about the turbo 400. thanks again.
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Re: Glide Vs turbo 400

Post by Coloradoracer » Tue Mar 22, 2016 8:26 pm

John Wallace wrote:Mark, are you running a PG in the dragster?

:?:

I am.
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Re: Glide Vs turbo 400

Post by Alan Roehrich » Wed Mar 23, 2016 12:45 am

Greenlight wrote:In a drag race only application, I have never seen a stock TH400 (no ultra-light parts) run quicker than a stock based Powerglide. When NHRA allowed Stock eliminator cars to run any "GM" transmission, most of the high HP cars that came from the factory with TH400 switched to either P.G. or TH200 transmissions. They ALL picked up a lot of ET. I suspect 0.15 seconds was typical.

Actually, in Stock Eliminator, if it came with a 3 speed, you have to run a 3 speed, no car that came with a TH 400 switched to a PowerGlide. Not legally, anyway.

If it came with a 4 speed automatic (overdrive) you can move back to a 3 speed.

Very few of the TH 400 cars swapped to a 200 Metric. Most went to an extremely trick TH 350. Some run a TH 350 with trick 904 TorqueFlite internals.

If both 3 speeds (TH 350 and TH 400) have all aluminum components, there will not be 0.15 between them. In fact, even switching to a 200 Metric won't gain you that much.
If the TH 400 has the straight cut gear set, the TH 350 may not be faster at all, a TH 400 with the new small diameter drums might even be quicker.

Most PowerGlide equipped Stock Eliminator cars (cars that were built with the PowerGlide, and previously required to retain it) have gone the other way. NHRA, about 2-3 years ago, allowed them to move up to a 3 speed. Most of the low HP cars went to a Metric 200, because a Stock Eliminator car almost always has a narrow power band, and when geared to have the best ET, run out of power and RPM. It's worse with a 2 speed. A Stock Eliminator car usually needs a lot of low gear to get off the line, simply not possible with a PowerGlide. And putting an ultra low 1st gear in the PowerGlide doesn't help, because most Stock Eliminator cars can't recover from the 1-2 gear change at that speed. A relatively heavy 283 powered car will often gain a tenth or so going from a PowerGlide to a 200 Metric.

Thomas Arnett is one of the best 200 Metric builders, he told me that his Metric 200 from his big block 69 Camaro might pick our big block 69 Camaro 0.02 over my ultra light low drag TH350. Scott McClay, another well known 200 Metric innovator said he wouldn't bet his 200 Metric would be measurably faster than my TH 350. Anthony Bertozzi swapped out a TH 350 identical to mine (I know, I freshened his transmission and swapped cases for him) for a Pro Trans trick TH 350 with the ultra light 904 Torqueflite internals, and said it wasn't more than 0.02 or so better than mine, either.

A typical 3300-3600# 396/375 or 427/425 Camaro runs a total low gear of 12.1:1 to around 13.5:1. To get there with the lowest possible PowerGlide first gear, you'd have to run a 5.57 rear gear. It would probably run out of RPM and power by 600 feet, and fall flat on its face, at best. It would have to turn close to 9000 RPM at the finish line, considering we turn near 8000 with a 4.88. I don't know anyone with a fast high HP big block car that can pull anything lower than a 5.14 gear. Most of those cars run a TH 350 with light planetaries, a drilled output shaft, and aluminum forward and direct drums. Maybe 1 out of 10 run a Metric 200. We run that combination because it will go around 500 passes with nothing more than a fluid change. It's not worth it to risk breakage and go to a high maintenance for a possible 0.02 ET. I could possibly get a little more trick with my TH 350 and gain that.

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