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Discussion Starter · #1 ·
will a 6 spd trans (t56 from 99 z28) work on a 4bt with a clutch disk from a z28 in a 4bt flywheel and Pressure plate not sure about the Pilot Bearing/Bushing :beer:
 

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Compare your transmission's input side to the GM SM465 in this thread:

http://4btswaps.com/forum/showthread.php?t=841

The important parts are the bolt pattern and the 6-1/2 inch stick out length. Also note the possibility of using an AA bellhousing with the Borg-Warner (Ford style) flywheel. Your clutch disk is probably a finer spline which as you stated could be swapped to work. I believe you would be the first to go this route.

Keep us posted on what it takes to put it all together.
 

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The only problem I see is that the lower gears are very tall (1st is 2.66 to 1, less than half of a NV4500's 1st gear), which is not very truck-friendly.
 

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The LS1 does not use a standard SBC bellhousing bolt pattern. Hence, the T56 from the 1998 - 2002 f-body will not bolt to the 4BT using the Chevy tranny adapter from the P30 van. The T56 from a 1993 - 1997 LT-1 equipped car uses a standard SBC bellhousing pattern, BUT it uses a proprietary flywheel and a pull type clutch. It also has a very shallow bellhousing. While the LT1 T56 will bolt to the 4BT Chevy adapter, it will be quite a challenge to get the clutch operational. Adapters are available to mate the LS1 T56 to a SBC bellhousing. Using one of these adapters will allow you to bolt the LS1 T56 to the 4BT Chevy adapter, but you will still have to sort out the clutch.

The 1994 - 2002 f-body T56 ratios are: 2.66/1.78/1.30/1.00/.74/.50. The Ford ZF S5-42 ratios are: 4.14/2.37/1.42/1.0/.77. With the T56, you will need to use a rear axle ratio of 5.50:1 in order to have the same mechanical advantage as the Ford ZF tranny using a 3.55 rear axle gear. The 9" Ford does have a 5.50 ratio ring & pinion available, but the gears have 33 & 6 teeth respectively making it one of the weaker gear sets. With a 5.50 axle ratio, you will be forced to tow in 6th gear. The T56 6th gear is not designed to handle towing.

While the LS1 T56 could probably be made to work, I don't think it is a good choice for a 4BT.

Mike
 

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Use a regular gear ratio...

You don't need a super low gear with the diesel engine since it has so much torque down low.

I'd say it would be a worthwhile swap since the viper spec T56s can handle like 600ftlbs or so. I'd say all you'd need to do is swap clutch discs.
 

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t56 trans

I put a 1995 t56 in my 1989 2 wheel short box chevy the trans does require a special flywheel with a pull style clutch proprietory to the lt1 or lst also this clutch is quite weak as I killed one in less than a year with a stock tbi 350 and 456 gears. The trans is extreamly high geared the the 456 gears it would still go faster in 5 than 6 because the 350 ran out of torque. If you are going to put in something heavy I wuld have at least 456 gears. The clutch could probally be handle by using an after martet slave cylinder that goes on the input shaft of the trans with some kind of heavy duty clutch.
 

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Mike is wrong about the LS1 bolt pattern. It is identical to a SBC, save one bolt. The second bolt from the top on the right hand side is not tapped in a LS1. You would use five bolts between the trans and engine rather than six. No adapters are required.
 

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Mike is wrong about the LS1 bolt pattern. It is identical to a SBC, save one bolt. The second bolt from the top on the right hand side is not tapped in a LS1. You would use five bolts between the trans and engine rather than six. No adapters are required.
Technically, you are correct. The LS1 T56 bellhousing will bolt to a SBC using 5 bolts, but GM intended the use of 6 bolts for a reason. Check the link below for the adpater plate.

http://www.americantouringspecialties.com/downloads/files/4.pdf


Mike
 

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Discussion Starter · #10 · (Edited)
pull type clutch?? it still pushes on the pressure so why is it called pull type clutch my 90 ford f-150 5spd has the same thing?? its all in the bell-housing instead of that arm and external Slave Cylinder.as long as it fits around the input shaft and it pushes on the fingers on the pressure plate thats all i need.and if the input shaft is to long or something ill cut it down :beer:eek:r am i all wrong about the clutch thing
 
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