69 C10 with a 6l90 transmission HELP

[reddogg]

Hoping to get some help. I have read that when putting a 6l90 that I would need to cut the floor and use the high hump. So I did that and put the cab in the frame and as you can see by the pic the end shaft and the 3 bolt flange are inside the cab. I have Holley motor mounts and tinworks frame stiffener with trans mount. I don’t know the angle of the engine and transmission. I know it should be 3 deg I just don’t know if that will give me the clearance I need. Let me know what I need to do. TIA

[notsolo]

Not the same as your application, but mine took 3 different motor mount combinations before getting engine placement correct.
.. More information needed for others to help solve your dilemma. Photos also get you better responses.....good luck.

[reddogg]

Pic

[Willie Makeit]

considered ditching the huge bolt flange and using a slip yoke?

[Joyridin]

I am a bit confused on your set-up. Do you have a picture of the crossmember mounted in the vehicle without the transmission? I do not see the crossmember by itself.

I have a 6l80 and granted it is a bit smaller, I doubt that would affect the mounting location. I have no problem at all with a high hump and a standard yoke.

[Accelo]

The output yolk style is different between the car and truck on this transmission. The 2-wheel drive truck transmission is harder to find. Getting a drive shaft to work for this transmission is a separate discussion. I did find a picture of the parts required to change a truck transmission to a Camaro, just to give you ideas.


I recommend getting the driveshaft type straightened out before committing to engine/transmission height as it is likely the transmission cross-member will require modification to get everything to work together.
Sometimes it requires a different tail shaft. Depending on which drive line style you choose.
If you measure the distance from the top of the cross-member to the center-line of the transmission output shaft it would establish a starting point. Is it possible the cross-member was designed for a more common conversion?

[AussieinNC]

A word of caution....the large tri flange drive system is designed to fit into a vehicle with a rear end that does not move relative to the vehicle chassis.

If the vehicle you are installing this into has a live rear axle, you MUST have some form of slip joint in the drive shaft to permit the driveshaft to move in and out of the transmission with the movement of the suspension.

Unless you are running something like a corvette independent rear end, you should have a slip joint in the driveshaft.

[reddogg]

I have the driveshaft taken care of through PST. It will have a slip yoke. I am just wondering about the clearance under the cab and the rear cab support it doesn’t seem like it will clear without cutting it

[Joyridin]

Originally Posted by reddogg

I have the driveshaft taken care of through PST. It will have a slip yoke. I am just wondering about the clearance under the cab and the rear cab support it doesn’t seem like it will clear without cutting it

Do you have a picture of the crossmember by itself?

[reddogg]

From the bottom

[Joyridin]

Originally Posted by reddogg

From the bottom

Where the rubber mounts sits on the crossmember is about 1.75" from the bottom of the frame. That is the dimension on my truck. I have a Tejas crossmember in my truck with a 6l80 transmission.

Just looking at yours, it looks to be a bit higher than that, but it is hard to tell. Your trans might be bigger than mine on the tailshaft also.

[reddogg]

Thank you for that it gives me something to work with.

[Shyster7]

Im running into the same issue you are. I have the qa1 front crossmember and engine mounts with a dirty dingo crossmember for my 6l80e. I ended up cutting more of the floor and modifying the high hump panel to clear the three bolt flange.

[bigmoe]

Reddog what angle is your motor sitting at? I used the smaller 4L60e and the low hump. The lowest angle I could get on the motor was almost 6 degrees.

[Hart_Rod]

Check my build out: https://67-72chevytrucks.com/vboard/...358692&page=17

[reddogg]

I ended up having to Refab the transmission crossmember. I am now sitting at about 4 deg and have cleared the bottom of the cab.