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#1
03-21-2016, 11:17 AM
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TH-400 Pump Question - 6 bolt or 8 bolt
I have two TH-400 cases that I dropped off to my builder & he just let me know that one has a 6 bolt pump & the other has an 8 bolt. He said that the 8 bolt case is the better of the 2, but it needs a new pump.
My question is: Is an 8 bolt pump better than a 6 (I've read conflicting info) and where is a good place to buy one? The trans will be getting a Jake's, stage 2, rebuild kit & will be going behind a 600hp+/- engine in a 67 bird. Thanks! ETA: Street car (mostly) no transbrake.
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No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017 
Last edited by Speargun; 03-21-2016 at 11:34 AM. |
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#2
03-21-2016, 04:58 PM
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Theoretically, the 8-bolt pump will hold "round" better.
Practice; no differences in Pump internals. Just the bolt holes drilled or not. MIGHT see less fluid weep from 2 less bolts... IF the converter was off-balance the 6-bolt might allow the hoola-hoop knock to give you a louder clue. IF the crank/converter/FWD pack/CenterSupport were off centerline the bushing Front Pump//FWD Pack Shaft will wear with either 8/6 front bolt count. In theory; both theory and practice are the same. In practice; practice and theory may differ.. |
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#3
03-21-2016, 05:43 PM
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Have him pull the pump on the 6 bolt case and make sure its not an 8 hole case with a 6 bolt pump. Pretty common to see that.
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Jack Ferris RestoRacing LLC www.restoracing.com Sandy, UT --------------------------------------------------- |
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#4
03-21-2016, 11:30 PM
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The T400s that I have done were all 8 bolt cases. Some had 6 bolt pumps but you could drill them out to 8 bolt if you wanted to. Have to have a nice drill press and transfer punches ect . Just never seen a case that only had the 6 bolt hole drilled and tapped from the factory.
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#5
03-22-2016, 08:43 AM
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Drill it out or just find an 8 bolt core.
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74 GTO Bracket/Street car and another 74 for the wifey to race with! 70 GTO 400, 4 spd, #'s matching and a little to nice for me to own. Friendship is like peeing your pants..everyone can see it but only you can feel the warmth! |
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#6
03-22-2016, 09:27 AM
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Problem solved.
He was under the impression that I wanted to use the 8 bolt case for the build. New question: Should I add a B&M "Shift Improver" kit (or something similar) to the build or is that really not necessary? I always thought those were mainly for people that just wanted to be able to chirp their tires in 2nd gear.
__________________
No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017
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#7
03-22-2016, 09:37 AM
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If you want to put a kit in it go with "Trans Go". Best I have used. You can duplicate the B&M level with just drilling out 2 holes in your stock separator plate and taking out a few of the steel balls.
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#8
03-22-2016, 10:02 AM
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Quote:
THIS ^^^^^^^ or my Recipe |
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#9
03-22-2016, 10:20 AM
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Which Trans Go kit?
Trans Go Kits I'm not looking to snap necks (or parts) every time I shift, but I do want good, quick shifts. Since it will see mostly street time, I plan on setting it up to shift automatically, but still be able to ratchet through the gears when the need arises.
__________________
No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017
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#10
03-22-2016, 11:26 PM
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If you bought jakes kit his website has a step by step way he does them. I did mine that way and shifts very nice and has held up 3 years going 10.80 and faster. If his site no longer has it team chevelle or google it. The kits do the same thing slightly easier but with cost. Rod
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#11
03-23-2016, 10:05 AM
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There isn't much tech info on his website, but Jake sent me this link that covers it.
http://www.crankshaftcoalition.com/w...0_rebuild_tech Thanks to everyone that replied here & thanks to Jake's Performance for providing a quick response to my email!
__________________
No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017
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#12
03-23-2016, 03:39 PM
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here from old website. http://jakesperformance.com/TH400_Rebuild_Tech.html
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#13
03-23-2016, 04:50 PM
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Quote:
That instruction set is okay. I would NOT perform the Manual 1st at any speed: DANGEROUS, and useless. Blocking the Reverse Feed: I block the tiny feed hole in the Separator Plate using 0-80 screw&nut rather than plug the Case; easier better faster lighter... That link makes it seem that Jake sends TH400s out with 5 Checkballs. Too bad. I'd use only 3 checkballs FOR BEST RESULTS. |
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#14
03-23-2016, 11:43 PM
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I put the 1st at any speed so it would not govern shift at 5600 rpm. There may be other ways but works very well in mine. All the previous 400 I built had a lag in the 2-3 shift of about 500 rpms. I do not know for sure which mod made that go away but it did. Rod
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