Back-half, Corvette C4 in 69

[PBFAB.COM]

Originally Posted by Rokcrln

A few more questions for you if you don't mind. With the vett set up out back what size tire/rim combo will fit between the bed lip and forward control links while still laying frame? Also if you can please explain to us theadvantage of this set up over a solid axel. Handling, bed floor clearance at same givin heights, tire size!

Thanks for your time. Also you have two packages headed your way

Kevin
LFD Inc.

I have not measured the max width tire/wheel combo we can fit back there yet. The new bed-sides and bed pieces will be here next week. I do know that I am running a 295 40R 20 on the blue 55 with a 20x10 and 7" backspacing. At full dump the tire is 1/16" (and that's a generous spec!) away from the stock upper link mounting bolt (the tires toe-in hard at full dump). We will be building our own links on this truck to make clearances a little more acceptable! Advantages to an IRS are all performance. It's true that a strait-axle can handle exceptionally well if set-up properly, but the function of an independently suspended rear is obvious. Advantages are gained in cornering, each wheel is allowed to react independently. As for bed floor clearance, the top of the framerail (2x4) sets 4" above the stock bed floor, and the frame lays on the groud with a 29" tall tire (to achieve this, new tie-rod links are made that relocate to the bottom side of the spindle, or rear hub, whatever you want to call it. If you want to keep stock tie-rod linkage, notch the frame a little, or move the whole thing up an inch). One main advantage to those of us who are afraid of heights and like to minimize the space between our frame-rails and the pavement is that the rear wheels camber in during bump (compression). This allows more clearance at the fender lip, minimizing bed hacking, and maximizing tire width! Besides, how cool is it when all four wheels are cambered in at full dump!!!!

[PBFAB.COM]

Originally Posted by blazntn

Did you have to narrow the rear any? What is the track width on it?

The rear-end is not narrowed. These suspensions do not lend themselves to being narrowed. It causes some major changes in the suspension geometry. The rear frame-rails do need to be narrowed. As for track width, I have those measurements at the shop. All the specs you will find on-line are from tire center to tire center, I have the hub to hub measurement at the shop, and will post it up on Wednesday. (I should know it by heart, but with so many measurements to remember, I just memorize where to find them, not what they are!)

[PBFAB.COM]

The C4 rear end measures 63.5" from hub face to hub face (this is with the rotors in place).

[Rokcrln]

Where are the new pic's I am starting to get the shake's and need a fix

Will a C4 front set up allow you to go as low as your drop member? Are their any advantages to it over the drop member other than all alum and much better brakes. I would think having matching brakes would make things alittle better for master cyclinder set up.

Kevin
LFD Inc.

[PBFAB.COM]

Originally Posted by Rokcrln

Where are the new pic's I am starting to get the shake's and need a fix

Will a C4 front set up allow you to go as low as your drop member? Are their any advantages to it over the drop member other than all alum and much better brakes. I would think having matching brakes would make things alittle better for master cyclinder set up.

Kevin
LFD Inc.

Meet me in the alley behind the liquor store on 3rd and Oak... I will be wearing a red baseball hat and white Reeboks.
I just unloaded all the new sheetmetal for the truck yesterday afternoon, and will be working on it again next week (late in the week). I have too many irons in the fire right now and am trying to keep everybody happy! As far as C4 up front there are some performance advantages to it. The design produces more camber gain and has a lower roll center than the truck front ends (dropmember included). Brakes are also a little better. Unsprung weight is greatly diminished due to the aluminum construction. As for allowing for the same drop, I am pretty sure it can lay frame and still have a 4.5" ride height, that's how I set em up on the 55-59 trucks. The only draw back is the difficulty in retro-fitting a C4 suspension to these trucks (63-87), not the price of components. A complete front end for the 88-96 Corvette can be found in wrecking yards for $800-$1100 in fairly good shape (you can then sell off the parts you don't use to re-coup a little cash). Tube arms, drop spindles, and new brakes will set you back beyond that price. True, it is by no means "cheap or inexpensive" and there may be some wear parts that need replaced, but it still probably isn't as expensive as most people might assume. I am working on a C4 bolt-in front end similar to the dropmember for 63-87 trucks... maybe it will make it a possibility for more people??????

[valleycustom]

I love your work!

[smbrouss70]

Originally Posted by porterbuilt

I am working on a C4 bolt-in front end similar to the dropmember for 63-87 trucks... maybe it will make it a possibility for more people??????

I'd probably buy that. I can weld and do some light fabrication, but when it comes to the front susp, I'm just a little weary of getting everything in just the right place. Although I might not be able to wait that long for you to come up with a kit, so I might just have to go with a dropmember. You do some amazing work to make it easier for the little guy. Do you offer any discounts for board members?

[onehot69stepside]

Originally Posted by porterbuilt

I am working on a C4 bolt-in front end similar to the dropmember for 63-87 trucks... maybe it will make it a possibility for more people??????

If you did some major marketing and advertisement, they would sell like hotcakes!

[bagged69c10]

I am very impressed. Its about time we see someone doing bad ass work and still putting the frame on the ground.

[PBFAB.COM]

Originally Posted by smbrouss70

Do you offer any discounts for board members?

I offer a 10% discount to board members (I just charge a 10% service fee first ). All joking aside, I do offer a discount to board members. The price I have advertised on the board for the Dropmember is the Board's price (already discounted), and I offer a 10% discount on air suspension components for board members (you have to PM me to recieve the discount, that way I know you're a board member for sure).
I do appreciate all the interest and compliments on the work, I take pride in what I do, and it's good to hear when people acknowledge it. Just don't get too carried away, I wouldn't want my head to get too big!

[Frizzle Fry]

Originally Posted by porterbuilt

...to achieve this, new tie-rod links are made that relocate to the bottom side of the spindle, or rear hub, whatever you want to call it.

I thought of this thread when I saw this:

[PBFAB.COM]

Originally Posted by Rokcrln

A few more questions for you if you don't mind. With the vett set up out back what size tire/rim combo will fit between the bed lip and forward control links while still laying frame? Also if you can please explain to us theadvantage of this set up over a solid axel. Handling, bed floor clearance at same givin heights, tire size!

Thanks for your time. Also you have two packages headed your way

Kevin
LFD Inc.

I don't know why I didn't think of this earlier, but one huge advantage of using an IRS like this C4 is the fact that the driveshaft stays stationary as the suspension goes through its travel. One huge obstacle when putting any vehicle on the ground (when they are equipped with a straight axle) is having to clearance everything for the driveshaft.
And Kevin, the step in the framerails are LESS with the C4 than a straight axle (by at least 4"), minimizing the amount the floor will have to be raised. You were right the whole time !

[72CSTC5]

Your fab work is incredible and this is from a guy that is EXTREMELY picky. You do incredible work. Keep us all inspired please as you build your customer's trucks.

[PBFAB.COM]

Did some more welding on the frame today, should have it all back together tomorrow.

[PBFAB.COM]

a couple more.

[blazntn]

Does anyone know how much a junk yard C4 rearend runs. I am thinkin about trying it myself if I can find one for fairly cheap.

[Rokcrln]

Show off!

Kevin
LFD Inc.

[PBFAB.COM]

Originally Posted by blazntn

Does anyone know how much a junk yard C4 rearend runs. I am thinkin about trying it myself if I can find one for fairly cheap.

They seem to be around $800-$1000. Sometimes more, sometimes less.

[FRENCHBLUE72]

Nathan congrats on the truck feature in classic trucks... Very nice work..

[gmcracing92]

i think that looks awesome. being someone who works in a fab/weld shop, i know quality when i see it, i also love the look of those welds, i didnt see one bad one.

[PBFAB.COM]

Originally Posted by gmcracing92

i think that looks awesome. being someone who works in a fab/weld shop, i know quality when i see it, i also love the look of those welds, i didnt see one bad one.

Thanks! Do you think I would POST a pic of a bad one!!!!

[70c10]

Can't wait to see the finished truck!. I just saw a cool 68' truck today on Craigslist that used a C4 rear under a modified 88' bed.

[cstanley]

awesome work!
a little hijack...would there be any advantage to going IRS on a mostly stock truck, daily driver, never intended on bagging (or really any substantial lowering?) the cool factor would be way on up there, but anything else gained? cornering, ride, clearance, etc?

also, would a lot of load (weight) capacity be lost?

[PBFAB.COM]

Originally Posted by cstanley

awesome work!
a little hijack...would there be any advantage to going IRS on a mostly stock truck, daily driver, never intended on bagging (or really any substantial lowering?) the cool factor would be way on up there, but anything else gained? cornering, ride, clearance, etc?

also, would a lot of load (weight) capacity be lost?

The cool factor would definitely be raised up a notch! As far as performance gains... there would be some, but to achieve the greatest gain, the truck would need to be lowered significantly. If you intended to leave the truck at a stock height, or slightly lower than stock, you would notice little gain in performance The load capacity would be diminished, but using a coil-over instead of the monoleaf would help.

[LUV2XCLR8]

Not to sound gay or anything, but will you marry me, I need your help