Raising engine crank centerline for better weight transfer (taller)

[corerftech]

Maybe not the most appropriate section to post this question or topic in, feel free to relocate as needed.

Building an ultra light 1987 std/std truck for street/strip use. It’s gutted (really gutted) and will fit NO specific class (and I don’t care).

it’s a really light truck with anticipated 475 hp. With just a bed, axle and bumper in back, plus a seat, steering wheel, engine/trans and cooling up front and inside- there is not much weight to send backwards.

I have contemplated moving the empty firewall back but it’s just cheaper/easier to leave as factory.
BUt like gassers from the 50s and 60s, I’d like to raise the crank centerline much higher to get some serious weight transfer happening.
Unlike a gasser I’ll have a reactive front end, meaning it will have shocks and coil springs and not a leaf and solid axle. It also won’t stick its nose up. But not having a good to contend with allows me to live the engine higher (and not rearward more than typical) and that will compound transfer.

So my concern/question;

carbureted engine
Blown
Float bowls need to be level side to side (engine for that matter) but also intake carb flange level front to back.

So am I raising the level engine straight up (altering the firewall relief and trans tunnel accordingly)?? Basically instead of a trans tunnel top of arch being around the hip height of a human, it’s probably several inches above that.

What I see is a really tall tunnel and firewall penetration. Entire drivetrain, without its slope altered from norm, moving straight up in the cab area.

This means my yoke will be very high and I’ll have to accommodate that with pinion angle to match as rear end is set up.

OR———

have I missed the concept?? What am I overlooking???

Headers will exit over the front tires and flow back outside the frame rails to the first bend and turn down.

I need some insight from someone who has seen a few gassers up close to see the trans tunnel and firewall pen for the bellhousing, and the engine bay- well enough to be able to speak into this.

I feel like it’s pretty straight forward! The possibilities are wide open endless with the carb being the single critical angle setting.
Again, what am I missing.

thanks in advance

mike in memphis

 

[Blmpkn]

Before you do all that...

Put battery behind axle? Taller, lighter springs in the front? Double adjustable shocks front & rear?

 

[alwaysFlOoReD]

I would look an leveling the carb with an adapter after setting up the engine. Custom phenolic spacer maybe?

 

[JOLENE_THE_RANGER]

you could design a 4 link system for the rear suspension with rear weight transfer characteristics? that would be the most effective way to gain traction with little weight back there. theres lots of online 4 link calculators that will help you position your link pivots in a manner to help you acheive less than 100% antisquat.

 

[19Walt93]

If you proceed you don't need to tip the pinion upward, the driveline angles front and rear should be equal and opposite. Unless you like the gasser look, I wouldn't do it, they ran nose high because the rear suspension set up wasn't figured out yet. When I was bracket racing, a guy had a Ranger bodied drag car with a 351W based engine that ran low 10's / high 9's and it sat pretty level. If you can tolerate the ride and handling, a ladder bar rear suspension can be made to hook up well and is simpler and cheaper than a 4 link. Just make sure it allows for pinion angle adjustment. A Mustang II based tubular front suspension would be a lot lighter and more adjustable, you could even use coil overs and change the ride height without replacing springs. I assume you'll run a fuel cell and locating it behind the axle will move a little weight. I'd also consider setting the engine back rather than raising it, even though it would mean fabricating mounts and such. Good luck and keep us posted.

 

[corerftech]

I bought two books that are old and on gassers (for sake of old tech).

The truck will have Caltracs on rear, narrowed 8.8, mono leaf springs. But I still don’t think it’s going to stick as well as I’d like.

I contemplated the carb correction plate, I have a phenolic 1” spacer and though——- why not mill it as a corrective spacer. So that is an answer to raising nose of engine and still maintaining some semblance of normalcy in the balance of driveline. If 2 degrees is typical crank angle (any height) then 4-5 would be double and only raise bellhousing/firewall intercept marginally. Tailshaft will drop. Nothing else in engine or a Jerico DR4 will demand that the drivetrain be flatter than 2 degrees.
The 2 degree rule of thumb is for U joint bearing safety, I don’t believe 4-5 would be excessive under high load. Up at 7 might be an issue.

Narrowing rear allows me to set the pinion angle when I weld up the leaf perches.
Contemplating raising the entire drivetrain end to end had me concerned about a top loader 4 shifter set that is already poorly placed in the little truck. Raising it 3 inches isn’t helping.

The added benefit (potentially) of raising engine is that if I didn’t go “full fabbed header” over the front tire, there would be significantly more header clearance at the frame and maybe an option or two that normally would be taboo, become available for use.

I get the rear suspension needs to be right, but if I can spend less on rear suspension and get a cheaper benefit by welding up taller engine mounts, well it needs consideration.

Truck not intended to mimic a gasser in form, just using gasser engine height as a reference for weight transfer improvement to rear.

Throwing spit balls on this- with hopes there may be some benefit.

 

[JOLENE_THE_RANGER]

theres an old saying around the desert racing scene....cheap fixes cost the most.

thats all.

 

[19Walt93]

I bought two books that are old and on gassers (for sake of old tech).

The truck will have Caltracs on rear, narrowed 8.8, mono leaf springs. But I still don’t think it’s going to stick as well as I’d like.

I contemplated the carb correction plate, I have a phenolic 1” spacer and though——- why not mill it as a corrective spacer. So that is an answer to raising nose of engine and still maintaining some semblance of normalcy in the balance of driveline. If 2 degrees is typical crank angle (any height) then 4-5 would be double and only raise bellhousing/firewall intercept marginally. Tailshaft will drop. Nothing else in engine or a Jerico DR4 will demand that the drivetrain be flatter than 2 degrees.
The 2 degree rule of thumb is for U joint bearing safety, I don’t believe 4-5 would be excessive under high load. Up at 7 might be an issue.

Narrowing rear allows me to set the pinion angle when I weld up the leaf perches.
Contemplating raising the entire drivetrain end to end had me concerned about a top loader 4 shifter set that is already poorly placed in the little truck. Raising it 3 inches isn’t helping.

The added benefit (potentially) of raising engine is that if I didn’t go “full fabbed header” over the front tire, there would be significantly more header clearance at the frame and maybe an option or two that normally would be taboo, become available for use.

I get the rear suspension needs to be right, but if I can spend less on rear suspension and get a cheaper benefit by welding up taller engine mounts, well it needs consideration.

Truck not intended to mimic a gasser in form, just using gasser engine height as a reference for weight transfer improvement to rear.

Throwing spit balls on this- with hopes there may be some benefit.

If you don't get the angle right or if you change the ride height like I did, there are angled pinion shims available to correct the angle and fix any vibrations that appear. I've seen Caltracs on leaf spring cars and they work great- and they're adjustable.

 

[corerftech]

The more I am reading about gassers and ramchargers of the 60s, the more I am convinced that an increase (not gasser levels!) in engine height will assist in a poor tire quality hook (with rear suspension changes as previously mentioned).

Have to wait a week for books to arrive, bummed. Microwave 2022 delivery apparently has me spoiled.

Most folks want a low mounted engine. It’s just better, safer at high speed, stable and as I have read, with current tire design, a non-issue. Coupled with chassis improvements, just keep it low.

Then there is the mentality/conditions of the 50s/60s: Poor suspension technology, lack of funding, poor tires. Those drivers did much with very little. That is not unlike my situation.

If raising the engine 2-3 inches is equivalent to setting back 2 inches (or even more reactive) then I believe it has merit. Of course the engine will be above the hood a bit so hiding the small block will be impossible. I have read that at the hit the transfer is massive but only for milliseconds. But as speed increases down track the transfer is recovered proportionately. So a moment of massive transfer, an unload and then reload, all varying with lots of reactive parts of the equation.
What is the worst case of I proceed?:
Forced to lower engine.
Maybe forced to change exhaust for clearance reasons
Forced to alter trans crossmember accordingly.
Potentially forced to adjust driveshaft length (unlikely)
Alter pinion angle (shims would accommodate and not a full re-weld of perches, etc).

I think that’s it. That is quite a bit of risk, exhaust the most concerning.

I appreciate the input folks, many thanks.

 

[snoranger]

I like that you’re trying something new (old? Whichever), but I think you’re barking up the wrong tree. Set your engine in as low and as far back as you can reasonably, build your suspension to work correctly, and fine tune it as necessary for track conditions.
I’d prefer to see the front spark plugs inline with the centerline of the front axle… maybe a little further back if possible. Keep the engine low for stability at the top end of the track.

You can get 475hp to hook up in the rain with the right suspension and tires. Your not building a 3000hp ProMod. A ladder bar suspension or even stock leaves with CalTracs should do what you want.