max recommended C notch to a stock 49 rear end

[sqweaka]

hi guys, whats the max recommended C notch i can do, to the rear of a 49 frame? half the frame depth? or can i go higher? i what to lay the frame as low as i can on bags without raising or cutting into the bed floor

[e015475]

I can't personally speak to the question about what the max recommended notch would be, but I found this analysis of c-notch configurations to be informative and provide some guidance on how far you can go-

http://talk.classicparts.com/showthr...light=notching

[Advanced Design]

Originally Posted by e015475

I can't personally speak to the question about what the max recommended notch would be, but I found this analysis of c-notch configurations to be informative and provide some guidance on how far you can go-

http://talk.classicparts.com/showthr...light=notching

Great thread! Thanks for sharing.

[sqweaka]

thanks for that link.. very informative indeed, so its looking like the bed floor is going to have to be raised as the only the last design in that link gave any strength to the frame

[1-ton of fun]

i wouldn't think you could notch more than about 3" without having to raise the bed floor, unless you put tubs in to deal with the frame kick up. the pumpkin would likely be getting close too.

[e015475]

One of the things you ought to consider is 'what's the intended use for my truck?' These trucks were designed as work-horses that carried a payload in the bed.

I doubt mine will ever see more than a beer-cooler and a few lawn-chairs. Towing anything with the truck isn't in the plan either.

If you were going to run a factory configuration leaf-spring rear diff where the spring shackle is behind the c-notch or you plan on a gas tank mounted behind the rear axle, you might want to be a little more conservative with retaining the factory strength with the c-notch installed.

The British saying "there's horses for courses" comes to mind.

[sqweaka]

hmm thats another consideration, if the only thing the rear of the frame is doing is holding up the bed. ie shocks and airbags mounted in front of the notch, does it need to be as strong!

[_Ogre]

good point sqweaka
if using stock springs and shock location, you'd need full strength
if you move all the action and load in front of the c-notch, your only supporting the bed
but... your supporting the bed for every bump and twist on a cantilever

you can also add to the frame up to the bed wood, similar to what i did
i added as much structure to the top of my frame as i could without raising the bed
with the bed sills on the frame i have 1/8'' to the bed floor, i have a static drop on semi-stock springs