L76/6L80E install questions

[1967wannabe]

Finally got my L76/6L80E combo stabbed with CPP mounts & stands and need some opinions.
1) I'm planning on a custom drive shaft so I see no reason to leave the motor so far forward, there's a ton of real estate between the motor and firewall, any reason to not move the motor back 4-6 inches?
2) I've seen the 5.3 truck motor with CPP mounts in 67-72's use the factory LS compressor & mounting, mine almost fit, I'll have a little more clearance once I move the motor back. Is the compressor mounting the same on the L76 as the truck LS?
3) The alternator also almost fit, 1/4" less frame rail and it would have slid right in. I plan on trimming the top of the frame rail back about 1/2" to facilitate the alternator as I like the accessories mounted low. I don't want to weaken the frame but it's already much narrower back by the upper control arms so I don't see how 1/2" trimming with affect the strength of the frame.
4) I've heard two opinions on the LS a/c compressor working with a Vintage air unit, anyone know the truth?
5) I had to pull the oil pan as it hits the crossmember, it's a Pontiac G8 pan which looks like a CTS-V pan, pretty sure it'll clear just fine if I move the motor back.

[nlped]

Subscribed!!! I'll be watching, because I am "sorta" doing the same thing, but with a 5.3L with the CPP stands and my motor seems to sit WAY far forward. I played around with moving the stands back to the V6 mounting holes, but the lower hole would require a lot of fabrication (which isn't totally outta the question) and I don't think my TBSS headers would fit then. Get to work.... So, I don't have too

[Hart_Rod]

I'm putting a LS3/6L80 in my 68 (thread in my signature) and I plan on moving it as far back as I can (I'm using the Dirty Dingo slider mounts). This will more than likely necessitate a switch to a high hump. Your stock oil pan will work once you move the motor back. A variable vane A/C compressor from vettes, camaros or anything else will work initially, but won't last (confirmed this with VA and several professional car building shops). Holley make a nice set of brackets that will let you use most of your factory accessories (except a/c) so that you won't have to cut the frame. I think the factory TBSS manifolds might work, but I know that factory 2010+ Camaro SS manifolds will. Do you have the triangle on your transmission ouptut shaft? If so, here's an option for your driveshaft:

http://www.driveshaftshop.com/domest...ece-driveshaft

[Travisc454]

Here is a cheaper way to do the driveshaft. It least i think so.
Link
It adapts to a 1350 flange.
Link

Then you can get the right splines and slip yoke to adapt to your existing driveshaft.
Link
Link
I am thinking about cutting my existing shaft and welding this assembly in. Then i will get it balanced. About $310 for the parts (from dennys, you may be able to find cheaper) I do know that the superduties have 1350 front driveshafts. If you scored one for cheap from a junkyard you could get the u-joint the slip yoke and i think even thing the flange from the cv joint will work. Or for 350 you can get a conversion tail housing. And install it yourself.

[1967wannabe]

Thanks for the input guys.

You say "conversion" tail housing, makes it sound aftermarket. Will a GM truck tail housing work or is the output shaft on the G8 different?

Yes, you will need a high hump. My transmission was way to low even when I had it jacked all the way up and hitting the cab floor. I moved the motor back 3.5 inches, installed a high hump and now it fits perfect.

Apparently I have the 3" forward version of the adapter plates (CPP's first design) which causes the DT 1 7/8 primary tube headers to contact the top of the tubular stands. So I got the grinder out, assuming I'd just have to knock the edge off of the top plate of the stands but no, by the time I was done grinding I was into the tubes and realized this ain't gonna work! After many calls to DT and CPP I've discovered that the original (3" fwd) adapter plates from CPP will not work with the larger tube DT headers. Jamie at DT said not to worry, they'll send me a different set of headers as soon as I call. CPP (that advertises this combo to work), on the other hand, keeps using phrases like "that's unfortunate" and "I'm sorry for your situation" instead of "how can we help"? Cool part is that I've spent $560 with DT and $4,694.44 with CPP so far

First pic is how far back I got the motor (you can just see the extent of the grinding), other pics are of another build on this forum with 1 5/8 DT headers that I think will work. Opinions?

[Travisc454]

Awesome! Now i definitely need to stop by and check your truck out. It will help me out big time to see how it all fits. These guys sell "conversion kit"
here about .625 down the page.
But I have a buddy who is a tranny guy (haha) at GM and he said all i need is 29544368 "extension" housing and 19260884 "gear" together those are $189 (you might need gasket and seal) through gm parts direct. He also said i would have no problem taking the whole trans down to swap the shaft. I have no clue if this is true, he said the only part that is hard is that there is a beast of a snap ring in the center support that requires the mother of all snap ring pliers (3' handled). he says its like a 2 hour job and its Way easier than the 4l80s and 4l60s to empty. But like i said this is hear say and im not sure. But i will find out soon hahaha.

[Travisc454]

$560 for the DT headers? website says $650.