Sweet drop kit for 67-72 C-20

[Jon Yaffe]

Hey guys,
I just registered for this site today; let me tell you, it's sweet. I have been looking for a good 67-72 truck forum for at least a year. I just found this place; what a blessing. Anyway, I wanted to let you C-20 guys know about a sweet breakthrough. I am currently developing a drop kit for 67-72 chevy/GMC 3/4T 2WD. I have been working on this for about 7 months as an independent study to recieve my master's degree in mechanical engineering. It should be entirely built and tested by this August. I am also hoping to start my own suspension design company by next year, and this should be a good start. I have been unable to find anybody that builds an entire kit for these trucks, which does not replace 3/4T components with 1/2T stuff. If anybody is interested in the specifics please let me know; however, I write this post for a more important reason.
I have been trying to research some weight ratings for these trucks, and GM won't help me. Can anybody can supply me with the following information: what is the factory payload capacity and the factory towing capacity (camper's special, or any big block/manual tranny)? Any good estimate of these would be appreciated. There is one other request; I am also looking for the factory curb weight of these trucks. I have measured mine to be about 3800lbs, but that was without a bed, and I don't really have the means to measure the weight of the bed. Even better, would be if anybody has placed scales under each tire to get an accurate weight distribution of the truck. I am currently working on trying to measure this, but a quick response would certainly help my efforts.
Thank you for all responses. I look forward to being a part of this awesome website.

[chevykevy]

Jon,

I recently acquired a 67 3/4 ton coil rear C20 Chevy. I was wondering about dropping it with the current components (ie. spindles and rear). What have you been working on?

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68 Chevy LWB CST project
67 Chevy 3/4 project

[Jon Yaffe]

Hey chevykevy;
Thanks for replying to my post. Unfortunately, this kit will require quite a few mods, which means it won't be cheap and easy. However, it's gonna be a real nice setup. I'll give you a quick overview, but I would prefer not to go into to much detail, because I am going to try and market this and also get a patent on the design. Here are some crucials:

Initial design incorporates 4"FR/6"RR of total drop.
Front: Retain stock spindles (allows use of both discs and drums),
Front: Replace stock upper and lower control arms with specifically designed tubular replacements.
Front: Replace stock coils with specific air springs.
Front: Replace stock shocks.
Front: Some additional small mods, including tie-rod improvements.
Rear: Replace stock 3-link or leaf spring setup with specifically designed tubular 3-link replacement and the use of air springs.
Rear: Replace stock shocks.
Rear: Some additional small mods, including driveshaft shortening.
Addtional add-ons: Recommend front, rear swaybars and the use of a Dana-60 rear axle (these won't be requirements).

Hopefully this gives you an idea of the things that will be required. As I said before, it may not be ready for the market till August, but when it is, I figure it will cost around $1500, which includes everything to drop the rig and make it roll. It's about the price of comparable kits for newer 1 ton chevys. The big things that I'm concentrating on is improved handling (cornering, acceleration, brake dive, etc.), ride quality and load capacity. The last thing I want is another 3/4T gone 1/2T, why destroy such an important feature? Also, there is now a decent amount of 8x6.5" wheels available in 18,20 and 22" sizes with tires also available that can handle heavy loads. So, no need to convert to 1/2T to get large wheels anymore!
Anyway, I definitely don't want this to look like an advertisement, because this is obviously not the place for it. Just let me know if you have anymore questions; I'll certainly be updating everyone on the progress of this new kit.

Sincerely,
Jon Yaffe