C10CJ: A Pro-touring '71 Stepside on a No Limit Pro-C10 Chassis

[1971_c10]

Hi All,

I'm a little behind on getting a build thread going. SCOTI gave me a reminder today so here I go ...

I'm currently in the midst of doing some MAJOR surgery to my '71 C10 I've had since the mid 90's.

I'll start off with the plans I put together way back in March of this year.

The 2016 Build:

Chassis/Suspension:
No Limit Engineering Pro-C10 Chassis

Moser 9" with 3.70 gears on a Detroit Tru-Trac diff

Wilwood 14" 6 piston up front, 12.88" 4 piston out back

Ridetech HQ coil overs (may upgrade to shockwaves down the road)

Engine/Trans:
Going to bite the LS bullet and do it! (Eng was a SBC)

Keep my PATC Level 4 Raptor 700-R4 with 10.5" billet 3200 RPM converter

Wheels:
TBD!

Body Mods:
Raised bed floor with mini-tubs

Rear mount fuel tank

Firewall cleanup

No changes to existing color.

The attached image shows my desired changes to the stance using my sub-par photoshop skills. Top row is where I started, bottom row is where I am headed. We'll see how close I can get.

I'm pretty far into the build, so the next series of posts may seem like I'm making really fast progress, but not so much. I'll let you know when the posts catch up to current progress.

[1971_c10]

How about some video fun?

Here is a timelapse of the teardown. It goes from complete running truck, all the way through bare frame. In the midst, I did a ton of measurements in order to determine what I wanted in the way of suspension. I also simulated my intended ride height to make sure I really liked it, before I committed to the suspension mods.

I'll say, I didn't start off with No Limit right off the bat. They were in a group of about 9 options. I had several options that I mulled over from several of the respected guys in the market, including Porter Built, Roadster Shop, and Hotchkis. I looked at replacement suspensions and full chassis. I'll tell you all about that in a future post.

Chevy Teardown Timelapse - YouTube

[smbrouss70]

I'm in for the ride. That No Limit chassis is in my list of possibilities for my SWB also.

[Advanced Design]

Cool project. I am tagging along.

[darkhorse970]

I'm in

[SCOTI]

In & watching....

[1971_c10]

I figure I’d start of with how I wound up at the No Limit Pro-C10 chassis. It was quite a journey.

It started off with tons of internet trolling through the build forums looking at what various people had learned through their process and also reading the make it handle threads that Rob has in several places. So in keeping with the theme and maybe helping others in their pursuit of upgrades, I give you my trials and tribulations.

My goals for suspension upgrades were basically improve handling and ride a ton with no strong desire to lay frame on this build. So I focused mainly on products with coil over options, but I also considered if I could swap out to air ride one day.

So here are the options I wound up with:
-Hotchkis TVS
-Porter Built Level 2 (coil overs)(I also looked at bagged setups)
-No Limit Pro-C10 Chassis
-No Limit Wide Ride IFS + Fat Bar (coil overs) (BTW, the No Limit trailing arm kit wasn’t out yet)
-Roadster Shop Revo Front and Rear Bolt in kits (coil overs)
-Roadster Shop Fast Track Chassis
-Roadster Shop Revo Chassis

Let me say, all those options are top notch. It was hard deciding, but a few things helped narrow down the list even further. First, I did not want to perform any serious body mods. I wanted to keep the body as stock looking as I can (but not resto stock, i.e. proper trim, paint colors, etc.). This eliminated the Roadster Shop Fast Track since that chassis requires something like slosh tubs up front, so now you loose your factory hood hinge and need a cowl mount which easily added over $1k in body work I didn’t want to do, not to mention you need a pretty healthy trans tunnel and I wanted to keep the low hump tunnel if I could.

Then, I made a video, which I’ll share below, that shows just how flimsy the stock frame can be if nothing is added to stiffen it up. Once I started getting all the costs added up (keeping in mind most of the chassis options include a rear axle housing, so I including rear axle upgrades in all options that weren’t full chassis) a full chassis was not much more when you consider it is a fully boxed frame with a huge center cross-member. So when you put it all into perspective, the full chassis came out the better overall value (yes, it cost more). And you see this value perspective with aftermarket companies that used to not make chassis replacements starting to make chassis replacements.

And as many of you know, you can put all the fancy suspension on you want, but if the chassis just twists away, then that fancy suspension isn't going to give you the full benefit. So it was either look into boxing in the stock chassis, or look at aftermarket options. I went aftermarket simply because I don't have the shop resources to do the kind of needed chassis mods and keep the chassis square. Yeah, I got a welder and could weld on some plates, but if I distort the chassis too much, no alignment will ever help.

So now I’m down to No Limit Pro-C10 chassis and Roadster Shop Revo chassis. Both are very comparable to each other. It was a hard decision to make because both companies do excellent work and both were very helpful on the phone in the sales phase. In the end, it came down to the No Limit chassis was slightly more aligned with where I wanted to take the truck, which is a fun cruiser that I can take to the local autocross/road coarse/drag strip on occasion and have some fun. Rob has a ton of experience in that realm and he frequents the forums quite a bit so that swayed me his direction, if not mainly because I can find setup advise fairly easily and know he puts all his track experience into his products.

With that, here is a mostly raw video of me just doing a simple test. Rob has actually started doing a similar test with a more objective result on various chassis he has round the shop. Check out their Facebook page for some of those videos.

C10 SWB Chassis Flex Test - YouTube

[1971_c10]

With the teardown complete, I had to do something with the old frame ...

[1971_c10]

Once I got the chassis on order, I then had to figure out what wheels I wanted and then decide, do I wait to get the truck back together and then order wheels or do I take a crap ton of measurements and order wheels off measurements and calculations? Well, I went the measurement route. It was painful, but worked out in the end. I did tons of body simulations using my old wheels (which won't fit on the new chassis) to get the wheel set in the wheel well and then I back calculated the backspace I would need based on the new track widths of the Pro-C10 which are different from the stock C10.

And yes, that is my front clip setup in my house. I put the clip at my estimated ride height, squared it up, then set tires in, looked at it, moved them, looked again, repeat until happy.

[1971_c10]

So one advantage of being behind on the build thread is those things that take months can happen over night. So one thing to remember when digging this far into your truck, whether going with a full chassis, sub frames, whatever, is that there can be substantial lead time. In the case of full chassis, you can expect around 12 weeks or more. It just takes time to build these things and these guys are busy, so remember to plan that in and be patient.

One thing that can be challenging is the shipping. I don't have a commercial shop with a dock, so getting the chassis from No Limit out east to my house in CO was interesting. But No Limit does this all the time. The have the crating down pat and figured out how to ship these things via UPS! ok. UPS Freight, but still ...

I arranged to pick the chassis up from the shipping depot. That was an interesting experience to say the least. The chassis ships on its side, and then we had to lay it down flat onto the trailer. I also had some interesting conversation with the guys at the UPS depot (which is also a regional distribution/transfer center). To paraphrase a couple guys "we've seen a lot of chassis come through here ... but none seem to be built as well as this one."

And yep, chassis came fully assembled. Of course, me being me I've take some of it back apart for various reasons.

[1971_c10]

In parallel with waiting on the chassis, I mentioned I did a bunch of body measurements. Those measurements were 2 fold, primary reason was getting wheel backspace, secondary reason was doing some ride height calcs, spring rates etc. I then built a somewhat complicated spreadsheet that also helped me pick the rear gears. Biggest part of the spreadsheet though was the total track width calculation which I then compared to those body measurements I took.

Then it was off to order some rims. I wound up going with Boze Alloys out of CA. They had a spoke style I really liked and are reasonably priced for a 2 piece forged setup. Again, like the chassis, custom wheels have long lead times too. Boze hit their lead time right on of 7 weeks, but a few later on the order and I could have been waiting 8-10 weeks. So you do that in series with the chassis (wait to do backspace until you can measure) and it could be at least 6-7 months before you have a rolling chassis. Luckily, you can measure and No Limit provides some guidance as well. But in the end, it's still up to you. I wanted the wheels to tuck, so I went a little off the No Limit recommendation. So far so good.

Here are all my specs:

Boze Tach (a new school/old school 5 spoke)

Front:
18x9 with a 4.75" backspace
275/40/18 Nitto 555 G2
results in about a 26.5" diameter
just under 11" total width

Rear:
18x10 with a 5.75" backspace
295/40/18 Nitto 555 G2
results in about a 27" diameter
just under 12" total width

[Advanced Design]

Very good explanation on lead times. A build really is managing a project. What are the graphs on your spreadsheet?

Impressive chassis! Did you go with a powder coat option? Those are good looking wheels.

[1971_c10]

Originally Posted by Advanced Design

Very good explanation on lead times. A build really is managing a project. What are the graphs on your spreadsheet?

Impressive chassis! Did you go with a powder coat option? Those are good looking wheels.

Thanks!

The graph is a plot of the gear ratios of the transmission I am running. The gear ratios are calculated all the way out (they include the rear axle ratio plus tire size), so the plot is vehicle speed vs engine RPM. The colored lines are each gear, and the black line is the trajectory the engine takes at a specified shift point (note, with an auto, you take the lower RPM stuff with a grain of salt due to the converter, but once above the stall speed, it's pretty accurate). This helps me understand that when I set a 6300 RPM shift point for say the drag strip, were will the engine bottom out on the next gear and will I be hitting the power curve of the engine in the sweet spot and will I dip under the converter stall speed for an auto. I also have a T56 (if I blow up the 700R4 I'm going T56) farther right that I didn't include since I was keeping the snapshot width to a min. It also helps to visualize how far apart the gears are just based on the space between the lines. This is useful since shops like Bowler offer a couple different gear ratio sets, so I can have a visual and numerical look at each gear set to make a more informed decision. I attached some close up shots to show you what I'm talking about. Also note, in the number shot, the line 'Distance per RPM' generally has different guidelines for different sports.

And yes, I went with the powder coat option through No Limit. I went with a color called "Black Magic" which I spotted on the chassis they sent to KC Paint shop for their SEMA builds and really liked it.

[Advanced Design]

Thanks, I appreciate the additional detail regarding the graphs. The calculations are a great way to compare the end result of all the variables. Did you build the calculations? Looks like Excel...

Bowler's shop is only 25 miles from me and I've been there a number of times.

[1971_c10]

Originally Posted by Advanced Design

Thanks, I appreciate the additional detail regarding the graphs. The calculations are a great way to compare the end result of all the variables. Did you build the calculations? Looks like Excel...

Bowler's shop is only 25 miles from me and I've been there a number of times.

No problem! I'm glad to help out in any way I can. And yes, I built the spreadsheet from scratch in you guessed it, excel. It is still a work in progress for the front axle, but the rear axle stuff is in pretty good shape. I still need to verify the coil over setup once I get the truck done. Might even pick up a set of scales for my shop since they've come down in price so much since I started working with corner scales.

That's cool you are so close to Bowler. I'm eyeballing one of their T56 with alternate gear ratios in the event my tanked out 700R4 isn't up to it. I would have swapped during this build, but I've had the 700R4 for awhile now, and no way I could sell it for even close to what it is worth with the ease of adapt for 4L60e or 6L80e these days. But, my 700R4 was purpose built for 750+ HP.

[rustylew]

I'm in.

[1971_c10]

Hey guys, sorry for a lack of updates recently. Been busy with the day job, and that doesn't let up until right before Christmas.

So I'm going to see if I can catch you guys up today, so please excuse the post blast.

Once I got the chassis, one of the first things I did was to level it and set the body on for a body fit check. This may seem like a lot of extra work, but I wanted to make sure the body didn't have any major issues once I went to set it on final, since it's a ton easier to do some mods, like on the cab, with the cab off and on a dolly.

Here's some pics showing the body fit. First on was the cab, then the bed, then the front clip and last the grill. I checked all the body lines and gaps during this process. I was impressed in that everything lined up very well with no shims. I had shims with the old chassis.

[1971_c10]

While I had the body on for a trial fit, I went ahead and did the mods to the inner fenders (wheel wells) on the front to clear the shock towers. The cuts may seem a little far back, but I wanted to have enough space to pull the coil overs out from the top.


I also added the holes for some vintage air AC which will be a nice upgrade from the heater only and make summer cruising much more enjoyable.

Just a note on the two circular vents for the vintage air AC. I did not use the supplied template to locate the holes. The supplied template puts the edge of the hole right on the radius of the gauge/glovebox feature, which would have resulted in a visible gap on top of the grommet around the vent. So you'd see if all the time. So I moved the hole down and out just enough to get on the flat part of the dash. This does put me very close to side of the cab on the backside of the dash making the supply ducts fit very tight, so I had to keep that in mind as I moved the holes.

[1971_c10]

Let's talk a little bit about the motor.

I had started off with a SBC. It was a good reliable running motor. I had slowly started adding more digital to it, so it had a full digital ignition. But, it still had a carb. I wanted to go full EFI. I knew I wanted sequential fuel and spark. I knew I wanted full closed loop lambda control (via wide band O2 sensors). I started looking at builds based on the Dart little M (or similar). I wanted a 4" crank. So that puts me in the 400+ cu in small block category. I was looking at some long blocks that were 427, 434 and 454 cu in from Ohio Crank. They were very tempting. I then planned to put either a Holley or Edelbrock EFI setup on the engine.

Then I came across Don Hardy Race Cars in Texas. They build LS engines. Hmmm. They have a 418 cu in LS3 making 620 HP. Hmmm. It's cheaper long block to long block than the SBC. Hmmm. Crap. I fell down the LS rabbit hole. I bought that LS3, all aluminum dressed with black billet. Oh man it looks good. But alas, I'm now falling down the LS rabbit hole and it's deep.

[1971_c10]

With most of the drive train, it was time to make a rolling chassis.

Started with bolting the LS3 to my existing 700R4 (its a built beast by the way, had it since 2012) with a 3200 RPM 10.5" billet converter (which I also had previously, fully intending to go to an engine with this exact power curve, of course back then it was a procharged SBC plan, not LS, but plans change).

Just a note on the 700R4 to LS3, the bellhousing bolts up just fine, only one less bolt and M10x1.5 now. The flex converter can be a challenge as the bolt circle on a 700R4 is 10.75" and the converter for a 4l60 (normally bolted to an LS) is 281 mm. They just don't line up. And it's not off by much. Some people elongate the holes on the base flexplate. however, I found that TCI makes a flexplate just for this purpose and is SFI rated. Perfect. TCI P/N 399753. It fit perfect, tooth clearance, started engagement, convertor pull out all within spec. The TCI kit also includes a "snout" to support the front of the older style converter.

I did have one little snag along the way. Remember that 4" stroke crank I mentioned? Well, it requires a little deeper oil pan up front. Specifically, it needs a Holley 302-1 vs the more common 302-2. The 302-2 is about 1" shallower in the nose, right where I hit the cross member on the No Limit chassis (shown in the last photo). Doh! I asked Rob early in the chassis build if a 302-1 would work and he said no problem, but I think that detail forgot to get written down. No worries, Rob made it right. I was a simple fix. The No Limit chassis has these removable motor perches on the truss mount that allow them to move the engine up and down as needed. So Rob sent me a set of plates with the motor a tad higher and that did the trick. I've got 1/8" clearance to the chassis now.

[1971_c10]

And alas ... chassis + wheels + drivetrain = roller

[1971_c10]

In parallel with the chassis work, I've been working on some firewall cleanup and other various minor body work. I did wind up having a little "fun" with the cab. I got that clutch rod hole all patched up and filled a bunch of smaller holes. Still have some holes to fill yet.

I was then staring at the engine/chassis one night. I was standing on the driver side. I remembered that the LS sits back around an inch from a SBC, and I had Rob set me up to put this thing as far back as he could. And he did. So then I did some measuring as I like to do (it's borderline OCD). Crunched some numbers, then got worried. So I set the cab back on the chassis ... and confirmed my worries. Not a clash, but too close for comfort. So I'll need to modify the recently patched area. Live and learn.

[1971_c10]

A couple shots with just the cab on. The first being a popular shot these days, straight on from the front. The second starting to show a bit of the stance.

[Advanced Design]

Well Chris, that is a very impressive LS rabbit hole you've gone down. Seems I remember Don Hardy race cars for V8 Vega kits back in the late 70's or early 80's.

Chassis and powertrain looks really good!

[mooseknuckles]

wow, I love that motor...and the chassis is pretty sweet too, and the wheels, and pretty much everything else. awesome build!