engine height for square tube mustang II

What's a good crankshaft center line height for a square tube Mustang II. It's a ladder-bar car with 14.5-32's
Thanks Joe

If it makes a lot of power mount it low and forward as you can. The ladder bar/ short wheelbase combo will be a hand full!

There is no one-size-fits-all crank nose height off the ground measurement for a full chassis car. Way too many other variables also play a part too like actual engine torque numbers (during launch) to work with, C/G placement (front-back & height), engine setback numbers, front & rear suspension types & the size of each's adjustment window, (& etc, etc, etc). But having said that I will say that a lot of people over the years have used the ancient/generic full chassis door car "crank nose at 10" off the ground on every damn car" thinking. Sometimes it works dead-nuts perfect, and sometimes it's waaay off. A lot of times it's just a coin flip where to put the engine, back & high, forward & low, or some combination somewhere in between.

As an extreme example take an ancient old-school Super Gas/bracket type full chassis door car with limited suspension adjustability (limited by today's standards anyway) with a healthy small block/lower HP big block. And lets say it was originally built with the engine sitting way back at/under the windshield, & with the crank nose sitting something like 12.5 to 13.5" (or more) off the ground. In this configuration it might have worked great for it's time & it's HP/TQ numbers. But take this same car & plug in an engine with big boy power numbers (and/or a big power adder) at the same engine placement & it can become a wheelstanding, tire spinning-shaking handful to get down the track regardless of chassis adjustments.

The other extreme would be a full chassis car built with the engine sitting farther out on the front of the car with the crank nose real low, like say only 9" off the ground (that's meant for big balls monster power). But it gets a low buck "bracket build" type engine instead of Godzilla type power. In this example the cars probably going to be super lazy/slow in the first 60-100ft cuz it doesn't have enough "grunt" to work with to plant the tire efficiently with the greater nose weight to get any initial weight transfer moving. In this case it could dead-hook, lug the engine, & fall flat on it's face not being able to get up-on the tire.....or it could just flat-out spin it's nuts-off.



But all this might be a moot point since this car was built long ago. The question might not be "where should I hang the engine" ....but might actually be "where will the car's older design/layout allow me to hang the engine". This is because an older ladder bar car might not have enough pinion angle adjustment (in the bars) to get the correct driveline angles if you don't hang the engine height exactly where the original chassis builder intended it to be.

That's why if it was my car I would first pull the coil springs off the rear shocks/front shocks. Then set the car on the ground & mock the car up at the correct ride height off the ground (using the coil over shock maker's center-to-center installed height specs) as if it was sitting at full race weight ride height off the ground. Then just take a look at exactly where the pinion it's self is pointing at & how much additional pinion adjustment the ladder bars might allow.

For example lets say you find that while sitting at ride height the bottom of the ladder bar is level with the ground while the front rod-end is sitting in the middle hole of the front ladder bar chassis bracket. And lets say that the pinion at this point is pointing downhill at 1.25* (in relation to the ground). And lets say that even though the ladder bar adjusters might have a very limited adjustment range that they can move the pinion angle up or down (from it's current 1.25* setting) it's current sitting in the very center of that limited adjustment range. And lets say for arguments sake you decide to use a -1.25* U-joint operating angle between the driveshaft & the pinion. That would pretty much mean you point the crank/trans centerline directly at the pinion centerline while the crank/trans centerline is also level with the ground.......and just let the crank nose height measurement off the ground land where ever it lands.