[4RSFEDGTO]

I'm installing a mid plate and motor plate on my 67 GTO and everyone is telling me the motor should sit offset to the passenger side 1/2". Mine is closer to center between the frame rails. That's with the stock frame mounts and motor mounts. I measured the pinion and it's offset 1/2" like everyone says. Do I just forget about the measurement and mount everything using the stock mounts as a guide? I think I'm overthinking all of this. Figure never hurts to ask for other peoples input...

[gman005]

I used the original mounts as a guide.

[GTO Dan]

Originally Posted by gman005

I used the original mounts as a guide.

X 2

[Tom Vaught]

Originally Posted by 4RSFEDGTO

I'm installing a mid plate and motor plate on my 67 GTO and everyone is telling me the motor should sit offset to the passenger side 1/2". Mine is closer to center between the frame rails. That's with the stock frame mounts and motor mounts. I measured the pinion and it's offset 1/2" like everyone says. Do I just forget about the measurement and mount everything using the stock mounts as a guide? I think I'm overthinking all of this. Figure never hurts to ask for other peoples input...

You might want to follow Jerry Bickel's suggestions in this link:

http://www.onallcylinders.com/2016/1...s-drag-racing/

He builds some very fast chassis.

Tom V.

He says put the crankshaft centerline and transmission shaft centerline EXACTLY down the centerline of the vehicle.

The OEM Engineers put the engine where they wanted it for Clearance with factory parts and the chassis structure.

[cgeise]

there is a train of thought that the offset is to help with weight bias to offset the side of the driver --

[taff2]

I offset my engine by 1" to the passenger side (our passenger side is on the left as you sit in the car 'cos we are right hand drive), this compensates for the drivers weight on the right hand side and helps to stop the left front end(as you sit in the car) of the car lifting too much. Ballast can do the same thing if your engine is on the centreline of the car.

[Kevspontiacs@aol.com]

Should the placement of the rear end come into play?
If you move the engine over an inch and a half should be pinion also be moved over the same amount?

[Tom Vaught]

The drawings I have seen show some slight offset is allowed left to right but the pinion yoke cannot point towards the tail stock yoke. One of those deals where the trans shaft center-line is on one plane and the yoke center-line is on a different plane but parallel.

Never claimed to be a chassis expert so only going by the "construction" plans I have seen for drag cars and road race cars.

There are images on the web that do a decent job of explaining the concept.
I do know that having the pinion yoke pointed upward is a bad idea.

Tom V.

[Kevspontiacs@aol.com]

I 'ASSUMED' a bit of an offset would be fine always best to ask

[tiacguy]

Iv'e built a few chassis and installed engine plates and what I found in most cases off setting the engine to the right is almost always a must in order to install the steering column with enough room for the exhaust. Even with using the rack steering you still need to get a steering column even w/joints through the left side to the rack or box is a challenge. This becomes even harder with the 28" wide chassis most mid size cars require. My 61 Tempest engine is 1.5" to the right and the car leaves straight and level and I have no anti roll bar on the car.

Wanted to add that I run a 9" Ford rear and my drive shaft crosses the car at a slight angle but is parallel. My cars been 138.00 MPH and no issues at all. It actually helps with phasing.

[GoatRider]

The article in Tom Vaught's first post was very informantive and helpfull without getting TOO technical. Thanks!

[Tom Vaught]

Jetty Bickel is a fine race car builder and an even better teacher and writer.

Jerry has built a couple of cars for Mike Cooper over the years. His old Tempest and now his Firebird.

You can obviously take his info to the bank. Glad it was helpful for the board.

Tom V.

[4RSFEDGTO]

Well I used the factory mounts as a guide and everything seems to line up with the rearend. Driveshaft is straight as an arrow. Hopefully it's all good..

[Tom Vaught]

Drive shaft should not be straight from the center of the trans shaft to the center of the pinion yoke. Trans shaft angle should be parallel to the yoke but not a straight line (looking from the side. If the yoke is pointing at the transmission, the yoke under acceleration will cause severe stress on the driveshaft. This might help a bit in racer terms, Mike. Image is good for a vehicle driven on the street at all.

http://www.superchevy.com/how-to/eng...203sc-driving/

Tom V.

[twooldgoats]

For a drag-only car, a straight line will work fine. For a street-driven car, it's best to have some angle (as shown in Tom's picture). Since I built my chassis from scratch, it worked out that my driveline is straight and level from front to back (except for one degree or so at the rear end to account for four-link slop taken up under the severe load of a pass). So far, no issues.

Jim

[4RSFEDGTO]

My motor angle and pinion angle are good. I was referring to the side to side. Up and down they are not directly in line. Car is primarily a grudge car with minimal street use....