Ls1 Engine Build - My First Stroker Part 4

Our project Trans Am's homebuilt 383 LS1 roars to life - will we have ourselves one helluva hot street/strip ride?

Alright--before getting to any results, let's talk money. Remember that we've gone through the trouble of building our own 383 Gen III from the ground up with the dual purposes of saving some cash and being able to say the phrase, "I did it all myself." The inestimable satisfaction of a job well done aside, was it really all worth the wallet hit? That is, what did we actually end up spending dollar-wise, and how does this weigh against buying a comparative complete engine and having the work done by a professional shop?

As much as we'd like to be able to give an absolute dollar value in savings, this isn't as easy as it might first seem. In fact, it's not possible to draw direct apples-to-apples comparisons for many reasons, a few of which are as follows. First, nobody sells a complete engine using the same parts that we've incorporated into this build, so an actual assessment of savings simply in assembly costs would be an exercise in pure speculation. Second, it's highly unlikely that a typical shop will install an engine that someone else has partially or completely built, meaning any separation of engine build costs from engine installation labor costs is artificial at best. Not to mention, all of the prices we've quoted in this build series are MSRP, meaning a lot of the parts we've used can probably be had for substantially less money from large retail suppliers. Perhaps worst of all, the total package we've brought together entails many components, some of which people would consider parts of a complete crate engine, others a part of a long-block, and some neither--people's definitions of these terms simply differ.

If you shop around, you'll find that you can buy a stroked LS1 for under $8,000 from some places--but this price generally doesn't even include the likes of an intake manifold, engine covers, throttle body--and often not even rocker arms. Considering that all of these items are included in what we've put together here, it means that the $8,000 number is pretty low. A more realistic assessment of the average comparably equipped engine would, by our count, probably be close to $12,000 (see "25 Hot EFI Crate Motors," April 2006). And then you're not even paying for installation, which as we've already mentioned is a complicating factor; though you might get fortunate and be able to have this done for a bit over $1,000 at a local shop, even this price would most likely only be for a very basic direct swap.

In our research, we did find a few sources that offered the kind of complete engine build and installation we've performed here. In doing some local shopping around in particular, the lowest overall price we found for a similar 383-inch engine with a good set of cylinder heads, cam, and big intake--installed and all--was well over $11,000.00. Look to some of the big-name, more-nationally known folks, and you're probably looking at a minimum of $15,000.00 for an installed stroker engine package--and that's likely with only ported stock (not aftermarket) heads and intake.

So since true comparisons are so difficult, let's do a rundown part-by-part to see where we're at with our particular build. We'll show what we've bought, whether it was a necessity for the build (or was more of a "luxury" option), and give some possible alternatives along the way for the truly budget-minded. See our prior "My First Stroker" installments for detailed part numbers and specifications on all of these items.

Let's first add up the parts needed to make the typical "long-block" you'd be able to find from your usual engine builder. Though long-blocks are, again, sold in differing configurations, we'll go with your most typical: fully complete engine internals and valvetrain, oil pump included, but no engine covers included:

As far as we can tell, this figure ends up being toward the higher end of the price spectrum for a comparatively equipped long-block--so at first glance, it may look as if our efforts were fruitless. But take a closer look at what we've done here, and we think you'll appreciate that there really are savings. In Lunati, we've got one of the strongest rotating assemblies on the market. Sitting atop our block are a sweet set of 11-degree aftermarket heads, whereas many engine builders use ported GM units. We've got the same shaft rocker arm system proven at endurance races throughout the world. And we have bulletproof main and head fasteners from ARP, where others often use OEM replacement stuff. If one were to make a few phone calls and specify these or similar top-tier options with some engine builders, we can almost guarantee that you'd be looking at substantially more than $10,000 for any given long-block. But if you're not looking for the kind of bulletproof setup we've ended up with, certainly as much as a few thousand bucks could be cut off of our dollar figure--just be aware that this will almost certainly come along with an incremental decrease in engine reliability.

Now, to put together a long-block such as ours, you'll of course need some of the specialized tools you've seen as this build progressed, and this cost can't be ignored. But keep in mind that nearly all of these tools can be reused in future engine builds or similar undertakings, so it's questionable whether they should really be considered part of the overall cost of the engine. Also, don't forget that many of them can likely be borrowed from local machine shops or your auto-enthusiast buds. But even assuming your social popularity is poor and you don't have any such contacts--and that you've already got yourself an array of sockets and a couple of good torque wrenches--here are all the tools you'll definitely need to buy to assemble an LS1 long-block (all items are from Powerhouse except as noted):

This brings our total long-block "assembly" cost to just over $10,580 (with a few dollars left out for miscellaneous assembly lubricants, sealants and solvents--items that cost less than $50 total and that we'll add into final figure below). And remember, we'd be shocked if you didn't reuse at least some of these tools on future engine builds or other projects around the garage.Actually spec'ing out how much we've spent in terms of a "crate engine" is far more difficult. Generally, this term defines a complete, turnkey engine that's meant to be dropped into an older GM ride that never had an LS1--or perhaps not even EFI. At a minimum, a crate motor most often includes additional parts like an intake manifold, throttle body, engine covers, and a harmonic damper. As applied to a mill destined for installation under the hood of an F-body or Vette, buying an engine so equipped saves the trouble of reinstalling many of these items--but it also means stuff like your existing engine covers or perhaps even the big-bore intake you installed last year might be duplicated. Unless you can auction off your used parts for decent coin, this translates to a waste of money. Adding more confusion into the mix, other times the crate engine term is applied to engines that include what might otherwise be called engine accessories, like ignition coils, fuel rails, and a water pump.

Since our project focused on a stroker build for your typical already-LS1-equipped ride, we're not going to add this complexity into the equation; we'll only include below what we ended up actually buying and leave it up to the reader to cross-reference these items with what might be needed (or desired) for a stroker swap into his or her own ride. That said, let's add up the parts we considered "necessary" for our particular build (this mostly means those parts that it would have been a bad idea to reuse from stock in terms of reliability), as well as those we didn't technically need, but are "nice to have" and will add to our performance potential nonetheless.

A few quick notes on the above: recall that it's best to borrow the alignment tools for the front and rear engine covers and oil pan since they're so expensive (in fact, they actually aren't absolutely necessary, but they're still a very good idea). Also, Wheel to Wheel Powertrain will install new crank seals in your existing front and rear cover for $139, so figure this in when pondering over gasket prices and install tools.

This brings us to the best estimate of our total stroker "crate motor" price, including all necessary and nice to have parts: $13,023 and some change. Adding in our few primarily cosmetic add-ons gives a modest increase over this:

Finally, to give a more realistic showing of how much it'll really cost to swap a stroker into your ride, we'll need to include miscellaneous stuff like fluids (coolant, oil, etc.), thread sealer, spark plugs, belts, clutch and flywheel bolts, a pilot bearing, and other miscellaneous last-minute stuff you may or may not need--and may already have lying around. Rather than listing every last one of these little items, we'll just say we spent in the neighborhood of $200 on them. Throwing another $450.00 or so on top of this for our mail-order tuning and $199.99 for our wideband, we'll even add in the $700 or so for a scanning and tuning tool like EFILive (which we had already--you may or may not; and don't forget such an item can be used to tune multiple vehicles).

So our absolute grand total--soup to nuts--comes to $14,765, give or take a few dollars. It's a good chunk of change; but remember, this price is for an installed, tuned (and further custom tuneable) engine package that is all-inclusive of some of the strongest and highest-quality components you can buy, and reflects the additional cost of more than a few parts that weren't actually necessary for the build. Recalling the prices we researched and reported above for an installed engine package, we're within the same price range, even if it's toward the upper end of it.

All that said, a couple of conclusions should be clear in the mind of the reader. First, the vast majority of engine builders and installers aren't ripping people off by any stretch of the imagination. It's a competitive market, and there are a lot of good deals out there when it comes to stroked LS1 engines, be it a long-block or a fully installed package; to make power costs money, and when you come down to it, there's no way around it. But more importantly, we hope we've shown that the avid enthusiast who likes to get his or her hands greasy can build an engine in the garage--and that by performing such an assembly at home and doing a lot of careful research, he or she can get some better-quality and higher-power-potential parts under the hood for an equivalent or lower price than the professionals offer their services for.

OK great, we've just built our own engine, and we did it while saving at least a little cash and simultaneously building in strength--and hopefully, horsepower--we may not have been able to afford otherwise. So what kind of performance results did we end up with? After a full break-in, we were ready to find out!First off, know that we're not turning the nitrous on just yet--we need to evaluate whether we have adequate fueling and what kind of tune changes we'll need, if any, for when the spray is engaged. (Ideally, we'd like to retard spark automatically when the nitrous is flowing rather than having to run a "de-tuned" calibration at all times. We hope to be installing products for this purpose in upcoming issues.)

This fact noted, check out the accompanying dyno charts for how our impressive torque curves and power numbers compare to our totals from our internally-stock LS1 engine, using both our Thunder Racing tune as well as our slightly-modified calibration. You'll note how power begins to fall off after peaking at around 6,200 rpm--higher than our stock engine's 5,500 peak, to be sure, but still a bit lower than might be expected. Let's keep in mind, however, that this 383 LS1 is a "small bore/long stroke" engine, with the 4-inch crank throw being large compared to the 3.903-inch bore. An engine with such characteristics often results in a downward "shift" in the powerband versus an equivalent displacement engine with a shorter stroke (and bigger bore). Also, we likely would have experienced an even higher power peak at a greater rpm had we gone with 225cc ETP heads in lieu of the 215cc units--but torque in the midrange may have suffered.

So you can see that we've gained nearly 100 hp and 75 lb-ft at the tires over our internally-stock LS1's dyno reading from immediately prior to the stroker installation. Admittedly, our 346-inch LS1's tune was running retarded timing to accommodate our nitrous shot, so horsepower and torque numbers would have been higher had we been using closer spark advance to what we are currently (18.5 degrees then versus 26.5 now). Still, it's probably safe to say that we've picked up around 100 hp at the engine, bringing crank totals to the neighborhood of 535 hp and 523 lb-ft SAE.

Also intriguing is the fact that although we performed slight adjustments to fuel and timing over Thunder's maps, torque and hp remained nearly identical. Apparently, the nearly 1 point leaner AFR we achieved was offset by the 1 to 1.5 degrees of timing we took out of the map. Though we're still at a slightly rich, mid-to-high 12s on the AFR with this tune, my lack of tuning experience told me to keep things as-is rather than risk leaning out further or adding a bit of spark advance only to achieve knock. I'll likely wait for a professional tuner to get his hands on the car before attempting to unlock any more horses (my guess: possibly as much as 20 rwhp is still on the table), or perhaps I'll brave the PE table a bit more myself on the next trip to the dyno.

As to strip testing, we didn't have a magazine-only track session available between the time of engine completion and the deadline for this story to go to print. I considered it an injustice, however, the keep readers waiting through this entire motor build series, only to end up without a single drag strip slip (as most of our readers are, admittedly, drag racers). This noble cause in mind, I braved a late August open test and tune night at Englishtown, New Jersey. Here, I was greeted by hundreds of racers (many of whom managed to spill fluids all over the racing surface and put a hold on racing for what seemed like hours at a time) and a grand total of three (3) strip passes. Despite my years of relatively successful racing of stick-shift GMs, somehow two of these runs resulted in my missing Third gear. On the one full run I did achieve, I was still a good bit off in the driving department, with a lackluster start and some of the slowest granny-shifts I have ever performed (images of Rick Jensen saying, "You're an embarrassment to GM High-Tech Performance," raced through my head). Never one to shroud his failures, I'll quote you the timeslip value anyway: 12.55 at 115.5, with a 2.15 60-ft.

Since I've gone through the trouble of giving you a drag result, do me one favor: please don't consider this a true showing of this car's potential by any measure. The same excuse has been used time and time again by pretty much everyone who has ever traversed the quarter-mile, but it's never been so true as it is here--with the right driving and decent weather, 11s are almost certain to be had as-is with this combination (or damn close to it). With the right gearing and tires, perhaps low 11s or even 10s... but notwithstanding all the extra gas, photo equipment, and Pirelli street radials adorning the car that August night, 12.55 is still the best ever ET for this vehicle--including the stock engine on laughing gas. Rest assured, we'll update you as improved drag strip times become available.


A closeup view of the controller box shows some notable details. On one end is the plug for the oxygen sensor to attach to (left). Coming off the opposite end are two thin serial in/out cables, which allow programming and monitoring of the system, as well as a thicker cable, which is shielded and contains the batch of wires that need to be hooked primarily to the vehicle. As you can see, the unit is sealed and weatherproof, so it can be mounted either inside or outside of the cockpit (zip ties are the preferred mounting method).

The ends of the controller's cables look as follows. In the upper right of the photo we see the serial in/out ports, to which connect either the provided 2.5mm male terminal plug and/or the provided 2.5mm stereo to DB-9 cable (the other end of which hooks to your laptop computer). As to the seven wires emerging from the thick shielded cable, they'll be tapped in as follows: red to an ignition-switched 12V source; blue (the sensor heater ground) will go to the chassis; black is the calibration wire that we'll be wiring to ground through a momentary switch and LED; white and green are system and analog grounds and will wire to our EFILive FlashScan cable; and yellow is the analog output and will also wire to our EFILive cable, providing EFILive with a voltage signal that will be translated into AFR. (The brown wire is a second analog output and won't be used in this application.)

Before wiring anything, let's install the hard parts. Innovate insists that the system's oxygen sensor be located prior to the catalytic converter on vehicles so equipped, as the company says the gas-altering nature of catalysts can alter the air-fuel ratio reading seen by the sensor. Not wanting to drill our headers, we opted to go right into our Dynatech cat housing with the sensor, and made the appropriate size hole using a drill press.

After ensuring the hole drilled is of adequate diameter (lay the bung over the hole and make sure no exhaust pipe metal is visible when looking through it), it's time to weld. Insert an appropriately sized bolt while doing this so that the bung stays centered over the hole; absolutely do not weld with the O2 installed into the bung! Tack the bung in place first, then check that the actual sensor screws in; verify and continue.

With the bung welded in place, the metal is allowed to cool before screwing the sensor in. Here we're looking into the inlet of the cat, which on this vehicle bolts directly to the header collector. As you can see, the sensor is now optimally placed to read the exhaust gas mixture just before it flows through the ceramic interior of the catalytic converter. Satisfied with our sensor placement and installation, the cat is then bolted in place in the exhaust system.

The LC-1 controller box is strapped securely to the underside of the transmission crossmember. On a Fourth Gen F-body, we found that it'd be easiest to interface with the vehicle's electrical system--and provide convenient hookups for a laptop--if the unit's cables were run directly into the vehicle's interior. The cables are so routed through a hole in the shifter boot, and are run carefully along transmission on their way so that they don't hit the spinning driveshaft or rub against anything that gets too hot.

Now it's a simple matter of plugging the wideband sensor into the LC-1 box, and the install underneath the vehicle is complete. Note that one must orient the sensor's placement about the exhaust pipe such that it falls between the 10 and 2 o'clock positions (to protect it from condensation that can form in the exhaust); happily, our cat was clock-able to allow this.

Inside the car, it's time to get the LC-1 wires we've poked up through the shifter boot hooked up. A pre-existing spaghetti mess of electrical wires under the console works our nitrous system and electric exhaust cutout--we tap into these wires and grounds as needed for the aforementioned volt sources. You can also see we've got the LC-1's green and white wires (combining into black) as well as its yellow wire connected to an EFILive-provided orange screw terminal, which will snap into EFILive's FlashScan interface cable. (We're glossing over some details here, but Innovate has a helpful tutorial on the company web site about wiring to EFILive.)

The aforementioned orange screw terminal pops into our EFILive FlashScan V1 Interface Cable "black box", which has built-in analog to digital converters and will provide interpreted voltage signals to the EFILive scan tool software. We'll note that when the LC-1 box is first powered, it'll need to calibrate the sensor's heater controller, as well as perform a "free air" calibration. These two operations will give the LC-1 information on how to properly warm up the sensor as well as tell it the oxygen content in the atmosphere, giving a baseline to reference to. It's important that every wire be hooked up before this calibration, including both plugging this terminal in here as well as connecting the FlashScan cable to the OBDII port under the vehicle's dash.

To begin the calibration process, the oxygen sensor must be unplugged from the LC-1 box underneath the car, powered for a few seconds, then turned off--this will reset the system. Plug the sensor back into the LC-1 box, and turn the ignition back on, at which time the LED you've wired in will flash in various ways for a few minutes while it performs these calibrations. Free air calibrations should be performed periodically (normally once a year), and rather than getting under the car and unplugging the sensor, you'll just need to press the momentary button I've got my hand on here--the heater calibration (which necessitates unplugging the actual sensor) need only be done once.

With the provided serial cable connected temporarily from the laptop to the serial out port of the LC-1, Innovate's provided LM Programmer software is used to program the LC-1's analog output with the correct voltage-versus-AFR curve to work with EFILive. Again, this information is provided in Innovate's tutorials. We'll also note that the LM Programmer software can be used for other functions, like setting the sensitivity of the analog output voltage. Because the LC-1's wideband sensor is so accurate, it can recognize individual pockets of exhaust gas as the cylinders pulse, and depending on the refresh rate of the data you are logging, this can cause the AFR reading to fluctuate somewhat artificially. It might be necessary to program the LC-1 such that the output voltage is averaged--for example, over the prior 0.3 seconds.


subscribe to the magazine

get digital get print