87CIZ

iTrader: (8)

In my buddies car, that we are swapping a carbed ls1 in to, we stuck with the 700r4 since it was already built and could totally get rid of the pcm. Problem we ran in to tonight is he bought the stainless works long tube swap headers from hawksthirdgenparts and they won't clear the 700's bellhousing. Any one have any experience with this? We're also running the Spohn swap tubular k member.

The headers are hitting the "ears" of the 700r4 bellhousing so tomorrow i'll be cutting those off. Any ill effects? Car is going to be sunny street driven and track car only so i don't think it will hurt open to the elements. flexplate and convertor will already be exposed to the elements.

Garry87IROC

I ran into the same issue and came up with the same solution. To cover up the flexplate and converter I picked up a chrome cover and made a bunch of modifications including a spacer made of square tube aluminum and drilled new mounting holes in the transmission flange. Not all that pretty, but seems to work.

ls six

Have you used a 1/2" spacer between the block and the bellhousing?

If not you are seriously risking your trans.


If you noticed, the back of the 3rd gen motors is different than the 1st and 2nd gen motors. The flange for the bellhousing is moved forward by about 1/2". There are two concerns here.

#1 is that the upper right bolt hole has been deleted from the 3rd gen block because there is zero space between the flange surface and the water jacket/cylinder bore.

#2 since the flywheel/flex plate surface on the crank is in the same position relative to the trans and the rest of the motor as the 1-2G crank the late 4L60E bellhousing is 1/2" deeper than the 700R4/early 60E trans.

Using an early 60 or 700 on a 3rd/4th gen motor moves the entire trans forward by 1/2".

What this means is there is little or no space between the converter hub and the inner pump body.

Even if there is some tiny amount of clearance left the flexing of the flex plate and or expansion of the converter will push the hub into the pump body and destroy it.


Get under the car, remove all the converter bolts and push the converter as far back as you can into the trans. If you dont have close to 1/2" clearance between the plate and converter you need to replace the trans or come up with a spacer.

87CIZ

iTrader: (8)

we used the conversion flexplate and spacer for the tranny. Our last problem is the long tubes, no idea why they won't fit.

ls six

Good deal then

The problem with the headers is the ears for the dust shield. The 4L60's used with 3rd/4th gen motors uses a modular 360* bellhousing. It actualy bolts to the cast pan around the bottom for stregnth and NVH reasons.

You can cut the ears and drive the car without issue though. I have the dust shield off of mine just because the Y pipe made it a pain to re-install.

87CIZ

iTrader: (8)

i cut the ears off but when trying to maneuver the headers in to place the collector hits the transmission pan. And one of the primaries is hitting the spohn k member keeping me from manuevering it out of the way.

ls six

Well that's an issue you run into when swapping non stock parts and aftermarket stuff.