engine and pinion angles

[Gary Seymour]

I will be swapping in a 351C and C6 in my '62 uni. I am also lowering the truck front and rear.

It seems the stance of the truck will effect the engine mount angle and pinion angle. So, does the final stance of the truck need to be determined before mounting the engine?

And for engine mounting, the base of the carb should be level, right?

[jwh f-100]

So, does the final stance of the truck need to be determined before mounting the engine?

Only if you are concerned with your oil pan/axle clearence. You can do it how ever you prefer. Adjusting the engine alignment should be the last thing you do..

I adjusted mine at the tranny crossmember. I used wood shims between the tranny crossmember and the bottom flange of the frame until I had it just right then drilled and bolted. The shims allowed me to remove the jack and have all of the weight completely on the truck.

[Rosati]

You need to set the frame on jack stands at finished ride height and angle.
The engine/trans attitude is determined by the carb surface, it should be level. This means the output shaft should run downhill (as viewed from the side) toward the back of the motor about 5 degrees (most if not all).
Once the engine angle is determined, you MUST set pinion angle the same angle and parallel to the output shaft of the trans.
You can tilt the pinion up a couple of degrees more to account for driveline torque if you want, but only if you really want to.

[Gary Seymour]

That's the way I have been thinking this through. Sometimes I think too much and dont get anything DONE. I am working on getting the truck sitting the way I want to - or at least real close with the spring work done and now my axle is dropped. Next will be the right size tires, discs and dual master cylinder set up. Then I will start the 351C / C6 swap. I can tweak the rear end height some if needed since there is probably some weight difference from the 292 and three-speed.

Thanks for the input!

[Rosati]

I can relate to the extended thinking processes!
I'm in my 6th year with this truck since I decided to actually do some work. It took me almost 4 years to get it road legal and still no paint!!!!

Tire size, spring rates, etc will have little effect on pinion angles. These are all relative to the frame.
The engine and trans are are, for ease of explanation, in a fixed position. So once the frame angle is determined, the engine and trans can be mounted. Once the rest of the drivetrain is installed and setting on the ground, you can use axle shims to adjust pinion angle.
Even if you change tire sizes, you will noy change the angle. Only adding weight to the rear of the vehicle, (ie change spring compression) will the pinion angle change.

Good luck.

[FORDMANLCRACKEL]

Nothing wrong with over thinking, sometimes it saves some $$$$$.

Lonnie

[pipedobber]

Gary, if you don't already have the C6, I would seriously consider an aod. My dad and I just built one and put it in my uni behind a 351C. With just a few small mods, a really stout unit. Chris

[Gary Seymour]

I thought about using an AOD. For what this truck will be used for, mainly running up an down the road in our area with exhaust cut-outs open, and doing smokey burnouts with a line-loc, I decided on a 3:25 trac-loc with a C6. You see, there are some folk that live out here that like to run their dirt bikes around.............. I think some flamethrowers would add to the effect nicely too.