7.5" rear behind a 455?

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Oct 14, 2008
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How tiny are spider gears in the Gov lock? I grenaded the stock open spider gears with a 403 with street tires, very soft and the first failure point then probably the 26 spline C clip axles then gears.
 

Bonnewagon

Rocket Powered Basset Hound
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Sep 18, 2009
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Eaton-style clutch pack, not the clockwork locker
I got the guv-lock carrier and set of 3:23's from John at Gevo's Gears and Rears. It stood up to the 400 no problem. Everything from towing boats to beer runs up the mountains in PA.
 
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spidereyes455

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Mar 6, 2013
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It will survive just fine under normal driving conditions. Start abusing it too hard and it will break. I've blown my share of 7.5's and it was always during a burnout or a hard launch. And it was always the spider gears that failed.
 
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Lowdollarbuild

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Dec 12, 2018
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If I put my factory stock Pontiac 455 w/MY6 overdrive trans in my Bonnewagon might the 7.5" rear live? I know most would say "fugedaboutit". But I ran the same 7.5" behind a harsh Pontiac 400 for 10 years with no issues. I think it would help that I already have the same 3:23 guv-lock gears in it as I did then. The trans has a 3:1 first gear which adds up to 9.69 overall ratio. I feel 10 to one is ideal and this gets me almost that. Then the .75 overdrive reduces the 3:23 to 2:42 which is some nice highway gearing. And of course I am an "adult driver" and I don't do crazy clutch dumping anymore. What I am asking is would a 7.5" rear last during everyday normal driving? Someone on here posted long ago about running a 455 w/Saginaw trans and 7.5" rear. He said be nice to it and it will live. I would not want to search out an 8.5" rear if I don't absolutely have to.
If you drive as if there is an egg on the pedal it will hold up. Wouldn't reccomend a shift kit or jack rabbit starts.
 

android211

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Oct 26, 2019
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I ran one behind a 500 Cadillac for awhile. No problems but it wasnt posi and I used stick size tires. Eventually I swapped in a 8.5 rear from a GN. If you just drive it normally or even full throttle as long as no slicks, shift kits or manual trans bang shifts.
 

lilbowtie

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Jan 7, 2006
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See, that is what I mean. Usually when I hear of a 7.5 or any other rear breaking it is a case of a big motor trying to push dead gears. Change to better gears- take the strain off- live a long time.

You have the 7.5 and by all means use it But if your going to invest money I wouldn't put it in a 7.5
 

pontiacgp

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Mar 31, 2006
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Mark, if you have a 7.5" in your wagon that had a stick and you towed your boat with it that would put more strain on the rear end the 455 unless you drive like a maniac
 
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icr242005

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Mar 3, 2018
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I have a 7.5 behind a 500HP 383. 3 to 4 passes at track, many miles on road with MT’s ET street and haven’t had a problem yet. If u treat it right it will treat u right.
 
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lilbowtie

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If you have that kind of power w/ what are slicks - you have an 11 second car, it's not if but when.
 
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icr242005

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Mar 3, 2018
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If you that kind of power w/ what are slicks - you have an 11 second car, it's not if but when.
Do what ? Are you saying a 500HP motor is guaranteed to be a 11 second car. Without knowing the rest of my set up, u r pretty damn good at this track time thing. Did I hit 11 secs at the track? No. Do I think it could? YES, if I pushed past the point I think the rear end and trans couldn’t handle it. Now go back and read the rest of my post. Treat it right and it WILL treat you right. I think u missed that part. All I’m saying is for a cruise car with street tires that DOESN’T get abused, that 7.5 will/can handle it.
 
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