I thought he meant at the engine. Even the 2016 Dodge Hellcat at 707hp is 650 ft-lb of torque and the mighty Cummins 6.7 turbo diesel is only 900 ft-lbs - at the engine. Of course there is a new aftermarket turbocharged HellCat that I saw in one of the magazines that is 900 hp. but didn't see a torque spec.

Regardless if you have driven anything with 500+ HP it is wild. When Viper went to 500 hp I did an accidental donut with one as I was used to the 450 hp version. No damage except to my shorts.

So if you are right about the 1200 ft-lbs being at the trans output then that is still a 480 hp engine using your 2.5 times number. That is a lot of power for a 1955 Ford Truck stock suspension. That truck will need a lot of modification to be able to handle that correctly. Otherwise "all show and no go".

 

I do not have the experience on these old trucks to say very much here, just remember to have fun, take pride in what you are doing, and be safe! When we put one of these golden oldies on the road we do have a responsibility to others on the roadways.
If this is your plan and you have the resources to pull it off good luck to you.

 

OK so there's a lot of talk about what the truck is gonna be used for. Primarily cruising with the occasional pass on the strip. It'll be trailer for long drives going to and from events but it will be driven.
The 1200 is not a multiplied number it's at the rear end where the rubber meets the road. Diesels have a near double he to torque ratio when done right. So the hp would be 600-650, and honestly that's not too much of an upgrade to the engine...medium injectors bigger turbo (or small compound set up)and it's done. The trans will be right about the same cost to build as the engine...and that will be an over built trans as well. The driveshaft is going to be a modified stock shafts from the loaner (03-07 f250) so that will be plenty strong. Suspension will be all replaced (ifs on front and 4 link 9in in the rear).
And yes ive driven 500hp vehicles...my daily driver (04 f250) has power ratio of 500hp and 900ft/lbs. I understand that's a bigger heavier modern frame vic, but that's the fun in building these things isn't it? Try something few have done?
I mean what about throwing fully built race engine in a 60s or 70s Mustang or even and old Vega...that's been done thousands of times and I doubt people were asking "why do you need all that power " constantly.
I'm a diesel guy it's my biggest hobby and love the effies so why now combine the 2?
I'm not trying to be disrespectful to any of yall but I came to you for help. But at the same time I asked a question about frame strength to experienced people. I know that everything is connected so there are other variables (trans, driveshaft, rear end, suspension, etc) but I'll worry about those later. But before I can I need to know that the frame I use will be able to handle it.
So again I apologize if I come over disrespectfully but whether you agree with my project or not, doesn't really concern me. I'm notrying trying to burn bridges either by any means...just looking for some insight.
Hope yall understand
Thanks

Jon

 

Jon.

Something I didn't realize when I first started looking at early F1's is the fact that the frame is actually designed to flex. If you look at the cab mounting it's really clever how it's decoupled from the frame so theoretically it should isolate the occupants a little from what the suspension and chassis is doing. As noted above that wasn't a problem for engines that put out a lot less that 200 lb ft of torque. You are asking the chassis to do something it was never designed to do and that will have undesired results.

A 500 HP diesel will have around 1200 lbft at the flywheel. You will multiply that flywheel torque through the transmission. You will have way more than 1200 lbft at the driveshaft. Do you know what transmission you are going to use? What's the first gear ratio? Multiply the torque by the first gear ratio, that's roughly maximum driveshaft torque.

You are going to be asking the frame to handle something like 8 to 10 times the load it does with a stock 239 V8 drivetrain.

 

I understand the frame is the weak point. I didn't know it was built to flex, that's why I made this thread. And that's they type of info I was looking for (which I'm glad I got). But wouldn't going with an aftermarket frame make that a mute point? Or are there other issues? For get about the power train for now...once the frame is swapped (whether with an aftermarket or modified modern frame) the strength issue is gone correct?

 

Frame flex, yes these old Ford frames do flex. How much flex before damage occurs? We don't know. If we knew the exact steel composition of the frame, factor in how much age deterioration, one of the engineers on here could probably figure out how much power the frame would handle.
Watch an OTR class 8 truck with a monster torque diesel engine get 40K lbs moving and you'll see lots of frame flex. It appears to me there is several inches of flex in those frames.

 

One of the strongest and stiffest frames that I am aware of for the F1 is the No Limit Big 10 chassis. For what you are intending to do something like this might work or would at least be a great starting point.



Compare the cross section of this chassis to a modern truck and it's very obvious that the current frames are much wider in section than this, more of a square section rather than a tall rectangle. Just that section difference will increase both the torsional strength and rigidity as well as the bending even over this custom designed frame.

Current F150 frame

 

Any aftermarket frame should flex/twist less than the stock frame. Some aftermarket frames are designed better than others. The best in my opinion is the Big-10 from No Limit Engineering in Tennessee:

 

Take a paper clip - Hold both ends and twist in opposite directions - That is an F1 chassis
Take a horse shoe - Hold both tips and twist in opposite directions - That is what you need per your original post

 

definitely not a semi a 3406b cat produced 1200ft lbs from factory more like 2200 ft lbs for an older pre 1990 semi and much greater for a brand new one

 

You have to look at the thread dates, the last post was over 6 years ago.