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

[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.