Slick 60's

Yep, right rail side in front of front axle. It usually consists of the prefix and suffix on separate lines without the basic (5005) part number. It will also have a date code below the numbers. Unfortunately it is often really hard to find and read. Thus the remark about checking tomorrow; I have several blasted frames which may reveal the data.
Paul

ICEMAN6166 wrote:no
rating is determined by the spring packs (and frame thickness, f250 has thicker frame than 100, 350 is thicker than 250)
flaresides came in f100, 250 and 350s

Your correct but the question I meant to ask had only to do with the F100 step and fleet side. I was wondering why swb F100's with same transmission, suspension and engine came with two or one piece drive shafts. As far as frame thickness of my two trucks I listed above, they are both 7/32 thick.

EDIT: The lwb F250 I own has the same front axles, spindles and springs as a half ton. Factory overloads and D60 4:10 rear axle. Maybe other variations of the F250 2wd had thicker frames?

somewhere i came across info that stated the f250 frame thickness was more than f100
going to see if i can find that again.
might be difference is between 2wd and 4x4.

chris401 wrote: I was wondering why swb F100's with same transmission, suspension and engine came with two or one piece drive shafts.

so you are saying swbs had 2 piece driveshafts

4x4 do in fact have a (slightly) thicker frame according to the "modulus" listing.
I have never encountered a swb with 2 piece shaft; certainly doesn't mean they did not make them. As to GVW, there were various combos, some designated by the VIN, some based on options and packages; and some dealer options. The F100 Camper Specials are a good example. The base GVW remained the same as the regular long bed, but the rear spring pack has considerably more leaves. The all-knowing parts catalog of the day did not spell out all these options, but replacements were available via VIN.
Paul

Chris, to my knowledge, GVW ratings do not take bed capacity into consideration. If there were a significant difference in the weight of the two configurations, then the lighter would be able to carry additional load to meet the common GVW. The one ton specialty beds are a good example; if equipped with a heavy after-market bed, the truck would have less actual load capacity than the same configuration with a lighter bed. I suspect (but don't know) that driveshaft selection was more dependent on potential pinion angles. By "fixing" one shaft, engineers could be certain there would be an adequate shaft to driver/ driven angularity under all conditions.
I need to research this; I am certain there are more criteria than I am considering!
Paul

I was wrong. I went and looked at my Cruse-O-Matic. Its a bolt on yoke, no carrier bearing, one piece drive shaft. I should have looked before I typed.

Toyz wrote:Chris, to my knowledge, GVW ratings do not take bed capacity into consideration. If there were a significant difference in the weight of the two configurations, then the lighter would be able to carry additional load to meet the common GVW. The one ton specialty beds are a good example; if equipped with a heavy after-market bed, the truck would have less actual load capacity than the same configuration with a lighter bed. I suspect (but don't know) that driveshaft selection was more dependent on potential pinion angles. By "fixing" one shaft, engineers could be certain there would be an adequate shaft to driver/ driven angularity under all conditions.
I need to research this; I am certain there are more criteria than I am considering!
Paul

Paul,
I'd be interested to hear what you research reveals......

BarnieTrk

Only additional info I gleaned is that the accepted maximum length appears to be around 70", which corresponds with the slick's longest listed shaft being 69.5". Seems this is based on the maximum practical weight and the sag involved. It was stated that a doubling of shaft length resulted in a fourfold increase in "whirling" , evidently related to sag. Thus, it would appear that modern shafts have somewhat reduced that problem with alloys and composites. Lincoln Mark VIII's had a problem with vibration even with a two piece setup. Changing to a one piece composite shaft solved that in my vehicles, and apparently others as well.
In an interesting footnote, my four cylinder Mustang SVO would develop a vibration within a short period of time even with an aluminum shaft. Painting a line the length of the shaft revealed the source of the problem. The driveshaft was twisting, even with the incredible torque of the Pinto motor! I wondered how people with big inch V8's handled that problem. I discovered it was often handled in the same manner I did; when it got noticeable, replace the shaft! Probably also explains the availability of used aluminum shafts on C/L !
Paul

For what it's worth, when i did the 460/C6 in my '66 I was going to use the driveshaft from a 1969 Cougar that had an FMX transmission in it. Lo and behold it was a perfect fit! I only had to trim the unsplined end off the slipyoke.

Toyz wrote:Only additional info I gleaned is that the accepted maximum length appears to be around 70", which corresponds with the slick's longest listed shaft being 69.5". Seems this is based on the maximum practical weight and the sag involved. It was stated that a doubling of shaft length resulted in a fourfold increase in "whirling" , evidently related to sag. Thus, it would appear that modern shafts have somewhat reduced that problem with alloys and composites. Lincoln Mark VIII's had a problem with vibration even with a two piece setup. Changing to a one piece composite shaft solved that in my vehicles, and apparently others as well.
In an interesting footnote, my four cylinder Mustang SVO would develop a vibration within a short period of time even with an aluminum shaft. Painting a line the length of the shaft revealed the source of the problem. The driveshaft was twisting, even with the incredible torque of the Pinto motor! I wondered how people with big inch V8's handled that problem. I discovered it was often handled in the same manner I did; when it got noticeable, replace the shaft! Probably also explains the availability of used aluminum shafts on C/L !
Paul

VERY Interesting, Paul!

Re: your 'twisting SVO' D/S; I assume you would place a straight edge along the painted line on the shaft, how much would it be twisted? 1/4" off of straight or ??

BarnieTrk

I actually put punch marks front and rear for reference. No straight edge needed; it was that obvious. I originally ran the stock non-World Class T-5 with the modified engine, which means an ultra-low 1st gear. I attributed the twisting partly to that until it repeated with the World Class and much more rear ratio.
Paul

That is all very interesting, Paul! Thanks for sharing!

During a recent "surfin' outing" on the subject, I came across this link: http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

Maybe you've seen it already, but I found it quite interesting.

BarnieTrk

I had the 69 shaft shortened and reused the new U joints that were in the 66 shaft.

BarnieTrk, thanks for the link! There's a lot of good info there, especially for our slicks. Considering the wave of lowered and raised trucks, as well as engine swaps, it would be recommended reading for anyone, especially concerning multiple plane angularity.
Of note also is that I have always set two piece shaft supports parallel to transmission, but not in the same plane; with the thought that
splitting the angularity between three points equally was the correct process. Guess I will go back and review Millwright 101
Thanks again,
Paul

Here is an (off-topic) link to driveshaft failures in late model V6 Mustangs. http://v6mustangperformance.com/modific ... riveshaft/
Think I will check my CS shaft for parallel and put it on the balance machine before the new engine goes in!
Paul