Thread: SBC in a model A chassis

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My question is what would be the best way to mount a SBC in a Model A frame. The frame has been Z'd 9 in. in the front. The problem is the Z is in front of the motor and if I use standard Model A mounts the oilpan hits the ground and the bellhousing won't fit. I've seen the taller motor mounts but have no idea where to get them. How much of a angle can the motor be mounted at? Any info would be helpful. Josh

"My question is what would be the best way to mount a SBC in a Model A frame"

Oil pan down, carburetor up.

Sorry, I couldn't help it

As far as motor mounts, you may have to fabricate some to custom fit the car. It's no big deal. Just get some cardboard and cut it with scissors or razor blade to the proper design, then transfer your pieces to 1/8" cold rolled steel and weld it up.

To get the proper tilt on the motor, have the car at ride height and level the motor by the carburetor pad on the intake manifold. This will angle the motor at 2 1/2 to 3 degrees, depending on the angle cut on the manifold. Use it to also level the motor side to side. It's ok if you have to move the motor to the passenger side a little to miss steering or headers, just make sure the centerline of the motor/trans is parallel with the centerline of the car. In other words, if you move the motor from centerline, DO NOT point the trans tailshaft at the center of the differential, point it straight back, no matter where it points to. The u-joints in the driveshaft will take care of the misalignment. That's their job. The pinion in the differential should point up about the same amount as the motor points down, 2 1/2 to 3 degrees for a street cruiser. If you will be drag racing some with the car, you might lay the pinion in at a lesser angle, maybe 1 to 1 1/2 degrees up.

Techinspector1, I'm unsure as to why it's necessary to line the engine trans with the centerline of the car. Seems like aiming it at the diff would give less angle to the u-joints. I'm not arguing, and haven't thought about that before, but I'm curious. There's a real possiblilty I'll run into just that problem with my Model A.

Lar.

Originally posted by biglar
Techinspector1, I'm unsure as to why it's necessary to line the engine trans with the centerline of the car. Seems like aiming it at the diff would give less angle to the u-joints. I'm not arguing, and haven't thought about that before, but I'm curious. There's a real possiblilty I'll run into just that problem with my Model A.

Lar.

The included angle of the two joints (front and rear combined) must be at zero to prevent vibration and premature failure.

If you have, for instance, zero lateral angle on the front joint and 5 degrees lateral angle on the rear joint, then the two joints are out of phase. If, again, for instance, you have the front joint at a lateral angle of 2 1/2 degrees and the rear joint at a lateral, but opposite 2 1/2 degrees, then you have a zero included angle and everything goes down the road happy.

Techinspector has just steered you on the straight and narrow.
Be assured what he has advised is factual.

When the driveshaft is at an angle, the universal joints speed up and slow down as they turn. IE as the engine universal speeds up, the axle universal slows down, and vise versa. If kept in parallel, they cancel each other out. If not kept in parallel, they will cause a vibration.