Custom engine perches and engine angle

[Red Lehr]

Howdy all.
Stupid question, should the FE engine mount perches be welded in level or at a 3 degree angle?
I'm currently working on my 64, Pro Street build. I have fabricated my own engine perches  and I am in the process of welding them in. I will be running a 427 with a dual quad tunnel wedge intake. I have the block, engine mounts, scatter shield and 4 speed toploader mocked up. My dilemma I have a six and a half inch drop from the end of my tail shaft to center of the differential. I have a four link suspension also. How big of a problem is it going to be with that much drop from the tail shaft to the differential?
The engine is sitting up higher so we can clear the Mustang 2 front end. Thank you in advance! See you all in September!
Red

[frnkeore]

You need to take out your X member and set the engine with a level on the carb pad and see how it aligns that way.

[machoneman]

Tim McAmis' vid may be of help. Note his mention of no set formula for engine angles. 

https://www.youtube.com/watch?v=fOsXndHxVyM

Then, check MW's link for driveshaft angle before doing any welding.

https://www.markwilliams.com/driveshaft-measuring.html

[Gaugster]

The pinion angle at the rear end will need to be equal but opposite to the engine angle. This should be the goal while under load and a bit more easy to set with a four link as you are less concerned about axle wrap. I've seen 2 degrees as a target but many other angles work well as stated above. You have a 6.5 inch drop but you should also look at the side to side offset. In the end try to minimize the angles by lowering the engine and raising the rear differential.

[My427stang]

Factory Ford had 3 degree tail down, that is measured as crank centerline, flywheel or bell, not carb pad. 

The idea is to have some u-joint needle bearing rotation due to a little difference in height and driveshaft yoke and crank centelrine on the same plane when under power.  As said above, what it is, is less important than being between 1.5-3-ish and parallel planes

[cjshaker]

With that 4 link, you should be able to crank a little positive angle to it, then modify the rear trans mount to drop to the correct angle to set your degree difference. Your trans is flat, and all factory engines had some drop at the rear anyway. The tunnelwedge will already have that angle built into the carb pad plane. I wouldn't think that would interfere with the Mustang II suspension, but don't know for sure. Maybe you'll have to raise the front a tad?

[GerryP]

I'm not sure how ubiquitous drivetrain down angle may be.  The FE in my '67 Fairlane is right at zero.  Checked with an angle finder on a machined surface on the front of the block with no obstructions.  Standard engine and trans mounts with everything in its stock location.

[Red Lehr]

Factory Ford had 3 degree tail down, that is measured as crank centerline, flywheel or bell, not carb pad. 

The idea is to have some u-joint needle bearing rotation due to a little difference in height and driveshaft yoke and crank centelrine on the same plane when under power.  As said above, what it is, is less important than being between 1.5-3-ish and parallel planes

Ross , does that mean that the engine perches would be welded in at the desired degree whether it be 1.5 to 3 degrees ?  There is only about .05 degrees give to the engine mounts when you put downward pressure on the tranny tail shaft.
Thanks,
Red

[My427stang]

So measuring angles like this is always tough because of a required reference point and suspension movement 

Both the crank centerline and the yoke have to be on the same angle to avoid vibration, problem is the axle yoke is moving, so generally the axle is a bit steeper to come up under acceleration.  A 4 link, if built correctly, should not move under torque, but if incorrectly built could move as the suspension flexes.  Likely something you want to check too

U-joints need some angle too, otherwise the joint doesn't force the rollers in the cap to "roll" they sort of sit there stagnant and wear

I would look close at this calculator and plug your numbers in.  Be sure to click "read more" that's where the good stuff is, this calculator takes out the variable of leveling the vehicle, you just plug in what you see with the suspension loaded and parts bolted together

https://spicerparts.com/calculators/driveline-operating-angle-calculator#more

In the end, if you are measuring the two angles correctly, looks like parallel and minimum of .05 is good enough, depending on the angle of the shaft, but I'd likely try to get it closer to 1-1.5 using their method.  Additionally, remember your driveshaft speed is your max RPM unless you run an OD tranny, then you have to divide your max RPM that you intend to run by the OD ratio

Hope this helps

[wowens]

This is usually ideal for street cars. For a well set up 4 link or ladder bars angles should decrease.