3.4 to 3.8 bell housing

[Ramchargerjay]

I'm wondering if the 3.8 in the Grand Prix has the same bell housing pattern as the 3.4 in my Montana. Will it bolt right up? If so are the flywheels and torque converters the same. Will the computer run the trans and new engine or will changes need to be made there? Any other thoughts? I plan on having a GTP parts car so I should have everything I need.

[joshuamc]

I might be wrong but no they are different I ask awhile ago I wanted to swap my 3.1grand prix trans to the 3.8s hd trans I think the 3.8 bolt pattern is the same as a v8

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[3400-95-Modified]

4T60E and 4T65E bolt patterns are the same and they used the 4T65E behind the 3800 motors and a 4T65E-HD on the 3800 SC'd engines. So to answer your question the 3400 and 3800 engine in the Grand Prix will share the same bell housing bolt pattern. Flywheels and torque converters may not be the same and the ECU may not run the trans if they are not the same version... I'm not sure what came in the Montana because you didn't list the year.

The bolt pattern for the HD trans never matched a V8 motor, but GM made a LS4 engine that matched the 4t65e-HD bolt pattern to be used in FWD applications like the GXP and so on.

[joshuamc]

Ok yea that sounds right it's been years since I did any research on it but I thought the 3.8s are in the sbc family

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[Guest]

Ok yea that sounds right it's been years since I did any research on it but I thought the 3.8s are in the sbc family

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3.8s from the early/mid '80's have the BOP pattern (still not the same as a SBC), but the 3800s use the "small corporate pattern", that the 60 degree V6s and several other engines use.

[Superdave]

Ok yea that sounds right it's been years since I did any research on it but I thought the 3.8s are in the sbc family

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You're thinking about the 4.3.

[joshuamc]

Yea but that's why I thought the 3.8 and 4.3 were the same

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[Guest]

Yea but that's why I thought the 3.8 and 4.3 were the same

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Nope, definitely not.

[Superdave]

Not at all.

I'm working on a RWD 3800 swap (2000 engine/trans) into an '84 Regal that has the old BOP 3.8. The 3800 has the same metric pattern as all my 60v6's did.

[joshuamc]

Not at all.

I'm working on a RWD 3800 swap (2000 engine/trans) into an '84 Regal that has the old BOP 3.8. The 3800 has the same metric pattern as all my 60v6's did.

So off subject but with that being said isn't there a 3.8 with a t56 in the 2000 fbody? So that bell housing bolt up to a 60degree v6?

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[joshuamc]

Scratch that I did some research no 3.8s got t56.well in America. That sucks lol

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