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2005 gmc
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2 Posts
Discussion Starter · #1 ·
Hi Guys,
I am putting a '05 4.2 L six cyl Envoy engine into my old "51 GMC pick-up. I also want to mate it to a standard transmission. I am looking to use a late model NV 3500 5 speed from a 1/2 t Sierra or Silverado. I am hoping that the trans bellhousing will fit the engine block and am willing to do some modifications if required. The big problem is that the Envoy crank is drilled for 8 bolts on a (approx) 3 3/8" bolt circle. I can't find any listing anywhere for a flywheel that will fit this configuration. Help!!! It looks like the flywheel from my selected donor vehicle(s) has the standard old 6 bolt design. Does anyone know what I can do. I am way into this conversion and really don't want to give up at this stage.
Thanks
Jeff
 

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2003 gmc envoy_slt
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7,190 Posts
:tiphat Welcome :tiphat .Have you tried emailing some of the flywheel manufacturers to see about a custom drill? Also, IIRC, the Canyon, Colorado, and H3 have the same engine but I-5. Is there a standard trans option for them? Good luck.
 

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2003 chevy trailblazer_ls_ext
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24 Posts
Hi Guys,
I am putting a '05 4.2 L six cyl Envoy engine into my old "51 GMC pick-up. I also want to mate it to a standard transmission. I am looking to use a late model NV 3500 5 speed from a 1/2 t Sierra or Silverado. I am hoping that the trans bellhousing will fit the engine block and am willing to do some modifications if required. The big problem is that the Envoy crank is drilled for 8 bolts on a (approx) 3 3/8" bolt circle. I can't find any listing anywhere for a flywheel that will fit this configuration. Help!!! It looks like the flywheel from my selected donor vehicle(s) has the standard old 6 bolt design. Does anyone know what I can do. I am way into this conversion and really don't want to give up at this stage.
Thanks
Jeff
I took a quick look at Summit's online catalog. I didn't see anything for the 4.2 I6. You might have to have something custom made (pricey!). If so you are going to have to determine if that engine is balanced internally or externally as this may affect the flywheel. If you are dealing with an external balanced engine,...I would highly recommend that you take the whole rotating assembly to a reputable machine shop and have it balanced.
 

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gmc
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830 Posts
Hi Guys,
I am putting a '05 4.2 L six cyl Envoy engine into my old "51 GMC pick-up. I also want to mate it to a standard transmission. I am looking to use a late model NV 3500 5 speed from a 1/2 t Sierra or Silverado. I am hoping that the trans bellhousing will fit the engine block and am willing to do some modifications if required. The big problem is that the Envoy crank is drilled for 8 bolts on a (approx) 3 3/8" bolt circle. I can't find any listing anywhere for a flywheel that will fit this configuration. Help!!! It looks like the flywheel from my selected donor vehicle(s) has the standard old 6 bolt design. Does anyone know what I can do. I am way into this conversion and really don't want to give up at this stage.
Thanks
Jeff

http://inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=50690#Post50690

This flywheel will fix your problem. Also PM I can provide more info.
 

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Registered
gmc
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830 Posts
Hi Guys,
I am putting a '05 4.2 L six cyl Envoy engine into my old "51 GMC pick-up. I also want to mate it to a standard transmission. I am looking to use a late model NV 3500 5 speed from a 1/2 t Sierra or Silverado. I am hoping that the trans bellhousing will fit the engine block and am willing to do some modifications if required. The big problem is that the Envoy crank is drilled for 8 bolts on a (approx) 3 3/8" bolt circle. I can't find any listing anywhere for a flywheel that will fit this configuration. Help!!! It looks like the flywheel from my selected donor vehicle(s) has the standard old 6 bolt design. Does anyone know what I can do. I am way into this conversion and really don't want to give up at this stage.
Thanks
Jeff

Here is a picture of a stock 4200 in my '51 GMC...

http://profile.imageshack.us/user/efi_diy/images/detail/#299/p9090075ck4.jpg
 
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