Chevy 350 Engine Build - The Chump Change Challenge

In These Recessionary Times, Can We Deliver 400 Hp For Under A Thousand Bucks?

Richard Holdener Oct 1, 2009 0 Comment(s)
Sucp_0910_02_z Chevy_350_engine_build Tune 1/25

Is it really possible to build an aluminum-headed 400hp small block for just $1,000?

In these uncertain times, enthusiasts are forced to watch every penny. That means maximizing power with a minimal expenditure. In most cases, it is necessary to trade the expense for either knowledge (of the likes you will find in the pages of Super Chevy) or good, old-fashioned, elbow grease. In the case of our Chump Change Challenge, we traded both.

The premise was a simple, albeit popular one. Take one small-block Chevy and select the most cost-effective components in order to achieve our seemingly conflicting goal of power and economy. On the power side, we selected 400 hp as a reasonable output. Building a 350 to produce 400hp is really no big deal, but doing it for chump change is decidedly more difficult.

In this case, chump change meant building our small-block with a ceiling of just $1,000. Given the fact that $1,000 is nearly the cost of a set of most aluminum cylinder heads, reaching 400 hp for a grand total of $1,000 looks pretty impressive-not to mention somewhat difficult. Now let's throw in the fact that the $1,000 price tag must also include not only the cost of the entire engine, but also a set of aluminum cylinder heads. Have we lost our minds?

Sucp_0910_03_z Chevy_350_engine_build 350 2/25

Some wheeling and dealing allowed us to score a TPI 350 minus the TPI induction and accessories for the paltry sum of $200.

Naturally, the 400hp motor was not going to be some off-the-shelf crate motor assembly, unless you count the shelf at your local wrecking yard. Remember we said that it might be necessary to trade cost for some elbow grease? In this case, the elbow grease came in the form of some computer legwork through the local Craigslist and Recycler, as well as a few trips to a nearby boneyard. Calling first, we found a few yards that offered complete engines for just $225 (plus a core of $50). Of course, the $225 examples were still installed in the vehicle, so this meant trading elbow grease for the additional cost savings.

Always up for a quickie R&R procedure, we ventured off to our favorite Pick Your Part in search of a low-buck (but hopefully fine-running) engine. Believe us, running engines (even good running ones) are out there for the taking. Given the sheer production numbers, this is especially true of small-block Chevys, though we made every effort to avoid the 305s and instead concentrated on finding a 350. The added displacement and bore size would help us achieve our goal on the limited budget available for performance parts.

Available in both cars and trucks, our only concern was to locate a good-running example with (hopefully) a 4-barrel Q-jet. Though we would be replacing the cast-iron 4-barrel intake manifold, the Q-jet was mandatory to help us achieve the desired power and keep us under the $1,000 mark. As it turned out, the search for the Q-Jet was unnecessary as a suitable candidate fell right in our laps.

Sucp_0910_05_z Chevy_350_engine_build Small_block 3/25

Initially, we searched the wrecking yards for a good used four-barrel small-block, but luck was on our side and we never even had to get our hands dirty (much).

Here are a couple of tips that might help you separate a usable small-block from the rest of the junk. First off, make sure that the engine in question has everything present that you will need to install in your vehicle. In most cases (like ours), the cost of the motor included everything from the air cleaner assembly down to the oil pan and from the fan to flex plate-including things like motor mounts, starter, and all of the accessories, though none of these would be run on the engine dyno.

After checking out the major components, it is time to look specifically at the engine to ascertain its health and viability as a candidate for your project. Check the coolant, oil, and spark plugs. The oil and coolant have likely been drained, but check inside the radiator cap or even in one of the radiator hoses for signs of antifreeze. Fresh antifreeze is a good sign, a rusty radiator or thermostat housing is not.

If the oil has been drained, smell the dipstick-does is smell like burnt oil? Even go to the trouble of removing the drain plug on the oil pan. Does the residual oil resemble sludge or is it clean? Don't confuse high mileage for abuse, as dark oil can mean that the motor simply needed an oil change and not a bearing change. Don't be afraid to yank a valve cover to verify the condition of the engine, as going to all the trouble of pulling a V-8 only to find out that it is a junker is huge waste of time and energy.

Sucp_0910_08_z Chevy_350_engine_build Exhaust_flow 7/25

The exhaust flow was equally impressive with nearly 190 cfm.

Check the spark plugs for signs that the engine was burning oil. Avoid engines with oil-contaminated plugs, but don't assume fresh plugs are the ultimate sign of a well-preserved motor. If the oil and plugs pass inspection, try spinning the motor over with a ratchet on the crank pulley. If it spins freely with no binding, chances are the bearings are in good shape. If you are allowed to bring a battery in to crank the motor over, by all means perform a compression check.

With tool chest in hand, we headed off to the wrecking yard in anticipation of pulling a small-block. Our trip was very successful, since we spent the majority of our time negotiating with the owner rather than knee-deep in used oil and tranny fluid performing an engine removal. This particular wrecking yard had a few engines already pulled and awaiting new homes. We happened to come on $200 Tuesday, which meant that any complete motor was available for just $200.

As luck would have it, this even applied to the ones previously pulled sitting in impound. Though there appeared to be one or two good carbureted candidates, what caught our eye was a pair of complete TPI motors, one iron headed and the other equipped with aluminum heads. Not surprisingly, these were set aside and were not available for the $200 price tag, but we were determined. A discussion with the owner revealed that the aluminum headed motor was indeed an L98 pulled from a Corvette (circa 1987) and the iron-headed piece was a 305 from an IROC Camaro. The owner wanted $750 for the aluminum-headed L98, but only $450 for the 305 TPI (both well out of our price range).

Sucp_0910_13_z Chevy_350_engine_build Combustion_chamber 8/25

The Pro Comp heads were available with a 64cc combustion chamber that helped maintain the original static compression ratio of roughly 9.3:1. The last thing we wanted to do was drop compression with a set of big-chamber heads.

Upon inspection, we discovered that the iron-headed small block was actually a 5.7L (350). We never mentioned that to the owner, but instead offered him $200 and allowing him to keep the TPI system, which was not useful for our needs. Not only did we get him to finally agree, but we got him to throw in used Holley 4-barrel carb (in need of a rebuild). Sweet!

The iron-headed TPI motor was quite a find, as it ensured we had a hydraulic roller cam and a decent compression ratio. The heads were to be replaced with low-buck aluminum castings (that's right, an aluminum-headed, 400hp small block for $1,000).

For our 400 hp application, we were not concerned with finding a four-bolt main 350 block. The two-bolt blocks are much more prevalent and more than stout enough for our 6,000 rpm (hydraulic roller) small-block. Having previously run 540 hp and 7,000 rpm on a two-bolt block, we were not concerned about using one here.

Sucp_0910_09_z Chevy_350_engine_build Valve_spring 9/25

Make sure when ordering the Pro Comp heads to step up to the valve spring upgrade. Upgrading the springs on the Pro Comp heads allowed out motor to run to 6,500 rpm without valve float.

The wrecking yard actually offered us a warranty (for an extra $12) that allowed us to return the motor for a replacement if it was internally damaged and unusable. As it turned out, the warranty money would have been wasted since our motor turned out to be a healthy customer. If offered, the warranty is still cheap insurance. Sure, you'd have to pull another motor, but you wouldn't be out the $200 if you found a spun bearing or some other malady that might keep you from using it immediately.

The final test was to check oil pressure. A new oil pump was not on the budget and we were hoping to get by with the stock pump. After filling the pan with Lucas synthetic 10W-40 and spinning the oil-pump driveshaft with an electric drill, we were rewarded with nearly 60 psi of cold oil pressure. We were in business.

Our TPI 350 was originally rated somewhere between 225 hp and 245 hp (depending on year). To reach our goal of 400 hp, we needed to address the fundamental restrictions to power production. First on the list was a set of cylinder heads. Initially we considered simply upgrading the existing heads with hand porting, milling and a valve job, but soon dismissed this idea after adding up the cost of all the proposed modifications to the stock heads. We were looking at a machining bill of near $350 to rework the stock heads.

Sucp_0910_11_z Chevy_350_engine_build L98_cam 13/25

Out came the L98 cam and in went the Comp Xtreme Energy profile. We made sure not to damage either the pan or front cover gaskets, though we had a new front cover gasket in our kit from Motorville.

After reviewing the cost associated with that, we decided to purchase a set of new aluminum heads from Pro Comp. The Pro Comp castings offered 190 cc intake ports, 70 cc exhaust ports and a 2.02/1.60 valve combination.

The big news was of course the aluminum construction (less weight than our iron factory heads) and the significant increase in port flow, not to mention the new valves, seals and a fresh valve job.

Where the stock GM L98 heads struggled to reach 200 cfm, the Pro Comp heads flowed nearly 250 cfm on the intake and 190 cfm on the exhaust side. These flow numbers offered by Pro Comp can be increased significantly through CNC porting for another $400-$550. Best of all, the 190 cc as-cast aluminum heads can be had (with a little haggling) for less than $600 on eBay. We got ours for $580, but figure on spending $600-$625 for a complete set.

The one potential downside to running the Pro Comp heads was the need for a different pushrod, which further increased our budget. A set of new 7.4-inch pushrods set us back just $29. It was an unnecessary expense to step up to the hardened (chrome moly) pushrods, since we planned to employ the stock guided rockers (eliminating the need for guide plates).

Sucp_0910_16_z Chevy_350_engine_build Roller_lifters 14/25

Since our late-model block featured a hydraulic roller cam, we simply reused the stock roller lifters.

For induction chores, we went to the guys at Professional Products for a single-plane Hurricane manifold. These intakes can be had for as little as $125 bucks via eBay. Having personally run the dyno testing, we can vouch for their performance.

After heads and intake, it was time for the camshaft. Obviously the stock TPI cam was not going to let our motor make anywhere near 400 hp despite the improvements to the induction system. With cost still a major issue, we let our fingers do the walking over the magic keyboard and found some low-buck hydraulic roller cams listed for $139. During our search, we found an honest-to-goodness Comp Xtreme Energy Cam listed on eBay for a reasonable $159. Though this was more of a one-shot deal, comparable cams (at least in specs if not quality) were available for less, we decided our find was legit.

The Xtreme Energy XR282HR offered a 0.510/0.520 lift split, a 230/236 duration split and a 110-degree lobe separation angle. In our quest to save money (it was after all a hydraulic roller), we simply reused the factory roller lifters.

After the compression and oil pressure test, the wrecking yard wonder was disassembled down to the bare short-block. We installed the new hydraulic roller cam using Lucas Oil assembly lube. Though we had no way of knowing the mileage on the used 350, the timing chain appeared to be in good shape and had minimal slop. Normally we'd change this, but we elected to save the $25-$50 cost of the replacement.

Sucp_0910_18_z Chevy_350_engine_build Guided_rockers 15/25

The new Pro Comp aluminum heads required the use of longer pushrods. Since we were running guided rockers, there was no need to use either guide plates or hardened pushrods. The cost of the replacement pushrods was $29.

We coated and installed the old lifters then installed the newly machined Pro Comp aluminum cylinder heads. We purchased a complete gasket set for the small-block from Motorville. The gasket set us back just $24.95 and included a pair of new head gaskets.

The heads were installed using the stock head bolts. Next came the longer pushrods and guided rockers along with a set of cast aluminum valve covers (also from Pro Comp). We then installed the new Professional Products single-plane intake, followed by our rebuilt Holley 750 carb. The stock HEI distributor was reused along with the plug wires (ours were in perfect shape after a quick cleaning). The final step was to bolt on a set of 13/4-inch dyno headers (not included in the build up cost) and our Chump Change 350 was ready for some dyno action.

The rings and bearing had long since been acquainted but the same could not be said for the new cam and roller lifters. Given the roller profile, a break-in procedure was not mandatory, but we elected to give all the new components time to get properly acquainted before letting the hammer fly.

The oil pressure looked steady at 55 psi and the motor sounded plenty healthy breathing through the 3-inch dyno exhaust. The initial pulls showed plenty of promise, with Chump Change pumping out more than 400 lb-ft of torque at 4,000 rpm.

We experimented with timing (eventually settling on 35 degrees) and minor jetting to the rebuilt Holley before letting the hammer fly. With a safe air/fuel mixture in the high 12s, the 350 eventually pumped out 407 hp at 5,900 rpm and 410 lb-ft of torque at 4,500 rpm. We had officially reached our goal of producing 400 hp.

The final bill for our 400hp build up checked in at $1,155, including the cost of the motor. We were excited about the 400hp peak number, but what really made us happy was the fact that this low-buck motor produced over 400 lb-ft of torque from 3,700-5,200 rpm. Even down at 3,000 rpm, Chump Change churned out 372 lb-ft of torque. Yes, we went $155 over budget, but the result is still affordable for most any enthusiast.

Sponsors
Comp Cams
901/795-2400
www.compcams.com

Pro Comp Electronics
909/605-1123
www.procompelectronics.com

Chump Change
Challenge 350 Pricing
Pro Comp Heads
$580.00
Professional Products Intake
$129.00
Complete 350 Motor, Pick-a-Part
(Wrecking Yard)
$200.00
Core charge
$0.00
Gaskets set- Motorville
(MRG-7100)
$25.00
E-Bay Comp Cam
$159.00
Pro Comp Cast
Aluminum Valve Covers
$33.00
Summit Racing Pushrods
$29.00
Chump Change Total Build Cost
$1155.00

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