tranny/rear end question
Thread Starter
Member
Joined: Sep 2007
Posts: 253
Likes: 1
From: Charlotte/Wilmington, NC
Car: 1991 Z/28 1LE
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42
tranny/rear end question
Alright, so I'll be getting a new engine soon, zz4, rated for 355 hp/405 ft-lb at the crank.
My car is a 6 cylinder right now. I've heard that the transmission was the same for 6 and 8 cylinder engines was the same, just with a different bell housing. Is there any truth to that? If not, will a 700r4 be strong enough?
Also, my rear end is non-LSD/Posi with drum brakes. Can I just buy an LSD rear end off the classified from an 8 cylinder and hook it up? If I get one with disc brakes will I need to change out the cylinders? Will that rear-end even be strong enough?
Thanks a bunch guys.
My car is a 6 cylinder right now. I've heard that the transmission was the same for 6 and 8 cylinder engines was the same, just with a different bell housing. Is there any truth to that? If not, will a 700r4 be strong enough?
Also, my rear end is non-LSD/Posi with drum brakes. Can I just buy an LSD rear end off the classified from an 8 cylinder and hook it up? If I get one with disc brakes will I need to change out the cylinders? Will that rear-end even be strong enough?
Thanks a bunch guys.
Joined: Sep 2005
Posts: 27,918
Likes: 2,448
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: tranny/rear end question
The transmission is the same MODEL (700-R4); but it is not THE SAME. The bolt pattern where it bolts to the engine is different, and the 6-cyl is altogether weenier inside (fewer clutches in the clutch packs, etc.) It does not have a "bell housing", the case is one giant piece including that section. So, no, it will not work. You need a V8 one.
Best thing to do for a rear is to get one from a LS1 car (98-02 V8) with a stick shift; it will have disk brakes, posi, and a decent gear (3.42). It will work with your existing hydraulics except that if it comes from a car with 4-channel ABS you will have to re-plumb the brake hydraulic lines because instead of one feed to both wheels like your car has, it will have separate right and left feeds; and some minor creativity will be required for the parking brake.
Best thing to do for a rear is to get one from a LS1 car (98-02 V8) with a stick shift; it will have disk brakes, posi, and a decent gear (3.42). It will work with your existing hydraulics except that if it comes from a car with 4-channel ABS you will have to re-plumb the brake hydraulic lines because instead of one feed to both wheels like your car has, it will have separate right and left feeds; and some minor creativity will be required for the parking brake.
Thread Starter
Member
Joined: Sep 2007
Posts: 253
Likes: 1
From: Charlotte/Wilmington, NC
Car: 1991 Z/28 1LE
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: tranny/rear end question
The transmission is the same MODEL (700-R4); but it is not THE SAME. The bolt pattern where it bolts to the engine is different, and the 6-cyl is altogether weenier inside (fewer clutches in the clutch packs, etc.) It does not have a "bell housing", the case is one giant piece including that section. So, no, it will not work. You need a V8 one.
Best thing to do for a rear is to get one from a LS1 car (98-02 V8) with a stick shift; it will have disk brakes, posi, and a decent gear (3.42). It will work with your existing hydraulics except that if it comes from a car with 4-channel ABS you will have to re-plumb the brake hydraulic lines because instead of one feed to both wheels like your car has, it will have separate right and left feeds; and some minor creativity will be required for the parking brake.
Best thing to do for a rear is to get one from a LS1 car (98-02 V8) with a stick shift; it will have disk brakes, posi, and a decent gear (3.42). It will work with your existing hydraulics except that if it comes from a car with 4-channel ABS you will have to re-plumb the brake hydraulic lines because instead of one feed to both wheels like your car has, it will have separate right and left feeds; and some minor creativity will be required for the parking brake.
And, will a stock tranny from an 8 cyl be able to handle the engine? If not, I'll just do one of the upgrades for it, but I'd rather know beforehand.
Yea, yea, I know, a shop is doing it. But it's a deal with my parents and they won't let me do it myself.
Joined: Sep 2005
Posts: 27,918
Likes: 2,448
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: tranny/rear end question
I can have a rear end with say, 2.73 gears right?
But then, why bother with all that motor?
Thread Starter
Member
Joined: Sep 2007
Posts: 253
Likes: 1
From: Charlotte/Wilmington, NC
Car: 1991 Z/28 1LE
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: tranny/rear end question
Well, I'm going to have 2 sets of gears. I already have 3.73's from when my car had a 350 ( it was originally a 350 car, but I sold the rear end when that engine died. same for the tranny.)
I was going to just put in the 2.73's for school, and over long breaks, like christmas, spring break, summer, etc, put in higher gears.
I just wanted to make sure that'd be kosher, that it wouldn't chew em up.
I was going to just put in the 2.73's for school, and over long breaks, like christmas, spring break, summer, etc, put in higher gears.
I just wanted to make sure that'd be kosher, that it wouldn't chew em up.
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: tranny/rear end question
Thread Starter
Member
Joined: Sep 2007
Posts: 253
Likes: 1
From: Charlotte/Wilmington, NC
Car: 1991 Z/28 1LE
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: tranny/rear end question
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Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: tranny/rear end question
Thread Starter
Member
Joined: Sep 2007
Posts: 253
Likes: 1
From: Charlotte/Wilmington, NC
Car: 1991 Z/28 1LE
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: tranny/rear end question
Oh, I've got the garage, the tools, and the know-how. I'd be doing it myself. I pretty much do all of my own work, the only reason I'm not doing the swap is because my parents are paying for it as a reward for getting a fat lot of scholarships, and they want a warranty with it.
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