I just had another epiphany about the design of the 53-56 frame and how they got away with such minimal frame rails; the bellhousing, engine and front engine mount were part of the design to stiffen the frame.

As we all know, the frame rails on the front of a F-100 are pretty flimsy. It's been common practice for engine swappers to weld in 'fish plate' to box the rails for additional strength.

I had already noticed that the bellhousing mounts were directly under the firewall of the cab, and that the firewall of the cab was mounted to the frame quite well. That all works as a unit; firewall, frame, bellhousing all lined up to resist engine torque.

But the frame, from the firewall forward, is a rather lightweight design. When I jack up my truck at one corner when the engine is out of the chassis, the twist in the frame is very easy to see. But today, while working on a 312 for my 54, it hit me how it all fit together - the bellhousing, engine, timing cover, front engine 'rest' all work to reinforce the front frame.

When you start to lift on one of the front corners of the frame when the engine is in place, the rather beefy front crossmember will start to lift on the engine, trying to twist it. The rear of the engine is bolted by its bellhousing to the frame on two widely spaced locations. The frame at the bellhousing is braced by firewall of the cab and that whole system will resist the twisting.

The front motor mount on a F-250 is a widely spread part that would stiffen the entire system even more.

If you stick with an early Ford engine (Ford/Merc Y-block, Lincoln Y-block, FE, or MEL), you can retain this design. Otherwise, you'd have to compensate by boxing the frame and worse.

 

OOOOOHHHHH Paul

Now you've gone and done it !!!! The darksiders will now know that their frames are puny, their 302 engines are girly motors and that Henry knew best.
Another blow struck for us stockers ! or nearly stockers or only mildly dark siders...

Great job and be ready to duck the slings and arrows of the dark side


In my command bunker with the catologue and hard hat

Bubba

 

But Bubba, the dark side has those puny, lightweight engine blocks! We've got big iron engines like the Y and the FE. No worries my friend, we can get away with light frames because we have such butch engine blocks.

Seriously, I think the Ford designers were exploiting the stiffness of the deep-skirt Y-engine block when they incorporated them into the design of the engine and frame.

 

55 F-100 has wimpy front frame??? My 55 has stiffer frame rails then my 67 F-100. Either way I have an FE sitting in it and its thick hide shows no twist when I stomp down on it. Have custom made tranny and motor mounts. Floor shift conversion doesn't budge on take off either. Are you real sure you ain't messing with a Chevy truck?

 

PC ,thanks for shining a light on this design strategy. Sure is good to keep that in mind before firing up hotwrenches.
Hey- formula 1 racers use the blocks as part of the frame- were our effies ahead of their time?
Compliant body on frame design may need lubing now and then but it works. Check the 04 F100 out- those hitech hydroformed metal pieces may make it stiff and quiet but now everything EXCEPT the motor is heavy.
Y blocks go fordever!

 

Once I took the cab off my truck and cut out my stock transmission mount I found my frame to be very weak. If I put my foot on the runing board bracket or front cab mount i could twist the whole frame from my front suspension back to the crossmember thats right under the back of the cab. After I tacked in my front boxing plates and new transmission mount the front of the frame was solid as a rock so I would definatly recomend boxing your frame if your removing the stock equipment.

Paul

 

The design of the earlier frames is a little better. The flathead and tranny were not adding any structure to the frame in my 53 F350, but the non removable tranny xmember sure does. I lucked out and can keep the stock tranny/bellhousing crossmember, the TH400 sits nicely above it so there's no reason to remove it.


Chuck P
53 F350 - 455 OLDS, TH400
46 CJ2a Rock Crawler
www.oldjeep.com

 

Thanks, PC, for givin' me one more reason to love my big ole Y-block.

Fads come and go (look at a late 70's Hot Rod magazine sometime), but STOCK will always be cool.

Fight's on,
ROB

 

Yeah, I like a nice 302W or 351C, but if I have to redesign the front frame to fit an engine properly, it makes a guy think twice.

If you want big power, there is a bellhousing to fit a FE or early MEL and those MEL's can be offset ground to give more than 500 cubes. But for a nice street vehicle, especially with gas prices the way they are, a Y-block is fine.

 

Pcmenten, Thanks for the 411 an dthe good discussion Thread!

GW

 

the original frames,with there underpowered original motors driven by old men on city streets will not be a problem most the time,BUT, add a load then drive them on uneven road conditions or better still on dirt roads, and the limitations will show, u may be very supprised at how many cracks appear when u sand blast what appears to be a nice looking frame. with the advent of modern motors, it makes more financial sence to repower than rebuild ( unless its a restore job), things move on, it is the styling of that period that attracks most, not the lack of power/braking/handling/etc etc etc, your comments are valid, but only one side of a varied topic.
cya..gary

 

just started my 54 and was looking at this very problem any help would be great.

 

What are your plans? A stock type engine like a 272, 292, or 312? Or a more modern engine like a girly 302?

If I were building for a modern, girly engine, I'd look into using pieces of another F-100 front end to box in the front frame. Cut the left side front frame rail off of a donor frame and weld it to your right side frame.

Although fish-plating a frame is fairly common, there are some serious drawbacks to that technique.

 

Not true ... true stockers embrace the feel of an old vehicle. Tastefully loose non-power steering, non-power brakes, etc. are all part of the old truck "scene." I, for one, wouldn't trade my little 223 for anything. She gets 16 MPG, which is about the same as my dad's '99 Suburban.

 

thats why i have all this nice tubbing laying around when im at that stage ill have full pics and designs