All the lit­tle de­tails for drop­ping in a new en­gine

Chevy High Performance - - Contents - TEXT & PHO­TOS: Jeff Smith

All the lit­tle de­tails for drop­ping in a new en­gine

An en­gine swap is likely the most time-hon­ored process within the art of car build­ing. Our grand­fa­thers likely strug­gled through it us­ing a ratch­et­ing come-along hung from a tree branch or a hastily welded A-frame that could have dou­bled as a kid’s swing set. To­day, we have bet­ter and more so­phis­ti­cated tools to do the job, but it still re­quires some prior plan­ning if the swap is to go smoothly. As with any other me­chan­i­cal ef­fort, a lit­tle pre­plan­ning can make the job much less frus­trat­ing. We’ll show you what we’ve learned and of­fer a few de­tails.

In our case, we were yank­ing a tired 383 out of our 1964 El Camino that was suf­fer­ing from a chronic case of GCS—Gi­gan­tic Cam Syn­drome—a mud­dled com­bi­na­tion of an overly long du­ra­tion cam ham­pered with low static com­pres­sion. It idled poorly, was gen­er­ally un­re­spon­sive to tun­ing, and de­manded a fat air/fuel ra­tio to run prop­erly. Ba­si­cally, as a parts-chaser and cruiser, the en­gine was un­der­whelm­ing and no fun to drive. This left us with a choice. We could pull the en­gine, change the cam, and do some­thing about the com­pres­sion or just slide in a brand-new Chevro­let Good­wrench crate en­gine that had a war­ranty. The new en­gine of­fered greater prom­ise and less has­sle.

The Good­wrench en­gine we chose is the stan­dard, two-piece rear main seal ver­sion that is both the least ex­pen­sive yet most pop­u­lar crate en­gine that Chevy of­fers. With 8.5:1 com­pres­sion, this 350ci will run on 87-oc­tane all day long with cam specs at 194/202-de­grees of du­ra­tion and 0.390/0.410-inch valve lift. Our sis­ter book Hot Rod tested one of these with long-tube head­ers and a Q-jet and made 249 hp, which is im­pres­sive since Chevy rates this en­gine at 195 hp. With ca­st­iron ex­haust man­i­folds, likely we’ll be mak­ing around 225 hp. For this ap­pli­ca­tion, it’s more than enough

when all we want to do is pick up bolts at the hard­ware store.

We’ve prob­a­bly mus­cled through this ’60’s mus­cle car en­gine swap a cou­ple of dozen times yet each one is al­ways a lit­tle dif­fer­ent. At first we didn’t an­tic­i­pate many hic­cups but from the be­gin­ning, lit­tle things promised to of­fer re­sis­tance. We’ve out­lined most of them here that you can use as guide­posts for your next en­gine swap ef­fort.

One lit­tle thing that promised to trip us up right out of the box is these Good­wrench en­gines come with pro­vi­sions for dip­sticks on both sides of the block. A plas­tic bag con­tain­ing two bal­ancer tim­ing tabs and two small steel plugs ac­com­pa­nies the en­gine. Choose the dip­stick style you want to run and use the ap­pro­pri­ate steel plug to seal the block on the op­po­site side. The block comes with lit­tle plas­tic plugs that are not in­tended to last long-term and will even­tu­ally leak badly, es­pe­cially the one down by the starter mo­tor on the right side. So make sure to plug the dip­stick hole you did not use. If you for­get, don’t blame us when it starts puk­ing oil.

Once we had un­boxed and painted the en­gine Chevy Or­ange, we re­al­ized that while some parts like the V-belt pul­leys and ac­ces­sory drive would swap over from our

pre­vi­ous en­gine, we needed a pile of new parts to com­plete this project. For ex­am­ple, the Good­wrench en­gine doesn’t come with an in­take man­i­fold and the old small-block ran Vortec heads. This meant we had to find a new in­take. Plus, the 383 is an ex­ter­nally balanced en­gine so we would not be able to use ei­ther the har­monic bal­ancer or the flex­plate.

We quickly de­cided to as­sem­ble a list of parts that should make this swap go a lit­tle smoother. It’s re­ally frus­trat­ing to have to stop in the midst of a project be­cause you lack the right parts. It’s bet­ter to plan the event through as many de­tails as pos­si­ble. Our list quickly grew nearly book length, which re­in­forces how many small parts are re­quired to com­plete even a sim­ple en­gine R&R.

For ex­am­ple, we orig­i­nally planned to re­tain the ra­di­a­tor, but closer in­spec­tion re­vealed a mi­nor leak had be­gun near the top of the core, which de­manded a re­place­ment. Sum­mit of­fers a bolt-in alu­minum, three-row ra­di­a­tor for our early A-body so we put in an or­der and it lit­er­ally showed up in two days. We also needed other small, yet im­por­tant items like new heater hose, nip­ples, and clamps as the old

ones were too abused to in­clude on a new en­gine.

With the old en­gine out, this is a great time to re­place the mo­tor mounts if they are weak. The TH350 we planned to use needed adapter fit­tings for the cooler lines to al­low us to use -6 AN hose be­tween the trans­mis­sion and the ra­di­a­tor. We’ve in­cluded those part num­bers as well. If you re­ally want to get down to the lit­tle de­tails, you might also need a length of 1/8-inch vacuum hose to con­nect be­tween straight man­i­fold vacuum and the vacuum mod­u­la­tor.

Since the in­take man­i­fold would not trans­fer, the best deal was one of Sum­mit’s in­take man­i­fold pack­ages with an alu­minum dual-plane in­take, one of Sum­mit’s an­nu­lar dis­charge 600-cfm car­bu­re­tors, gas­kets, bolts, and RTV. We’ve in­cluded the kit as well as the sep­a­rate part num­bers for the in­take and car­bu­re­tor. The carb is not a tra­di­tional 4150 style Hol­ley, but in pre­vi­ous test­ing it ran great on the dyno be­cause of its

an­nu­lar dis­charge boost­ers. It uses many tra­di­tional Hol­ley parts like jets and the ac­cel­er­a­tor pump di­aphragm so tun­ing it shouldn’t be a prob­lem.

The dis­trib­u­tor had to re­main with the pre­vi­ous en­gine as it was des­tined for an­other project so we opted for a new HEI from Sum­mit to fill that void. We also added new spark plugs and wires and set the ini­tial tim­ing at 12 de­grees BTDC.

Be­cause this is a flat tap­pet camshaft en­gine, we were con­cerned with proper break-in pro­ce­dures. The key to proper cam sur­vival is us­ing high-qual­ity break-in oil so we added five quarts of Lu­cas 30w Break-In oil to en­sure that process would go well. Then we pres­sure-lubed the en­gine be­fore­hand to en­sure that oil pumped to all 16 rock­ers be­fore in­stalling the en­gine.

With all the pe­riph­er­als in­stalled, in­clud­ing coolant, we pre-filled the car­bu­re­tor by pour­ing gaso­line through the vent tube so the en­gine would start on the first crank. Af­ter the en­gine started, we quickly brought the rpm up to 1,500 and then var­ied that by 300 to 400 rpm for the first 10 min­utes to make sure the lifters were con­stantly splashed with oil. Then we shut the en­gine down and al­lowed it to cool for a half-hour and but­toned up any re­main­ing de­tails and to make sure we had no leaks.

Af­ter con­firm­ing all our con­nec­tions were tight and mak­ing sure the throt­tle link­age of­fered free move­ment, we promptly fired the new en­gine and im­me­di­ately put it on the road to load the rings and break them in. We had a scare when the temp gauge hit 220 de­grees but within a block af­ter we turned around, the gauge dropped back to 180. It’s pos­si­ble the new ther­mo­stat stuck for a mo­ment be­fore open­ing.

There are dozens of opin­ions on how to break-in a new en­gine, but pis­ton ring engi­neers and pro­fes­sional en­gine builders all agree that ex­tended idling over very light throt­tle run­ning is the wrong way. In­stead, they rec­om­mend ap­ply­ing load as soon as the en­gine reaches a nor­mal op­er­at­ing tem­per­a­ture. Var­ied light ac­cel­er­a­tion for the first 10 min­utes fol­lowed by suc­ces­sively higher loads is the best way. Af­ter 15 min­utes of that, try a cou­ple 75-per­cent throt­tle runs fol­lowed by a few wide-open-throt­tle events in a safe, le­gal lo­ca­tion away from traf­fic.

Once we com­pleted our break-in and drove the car for about 100 miles, we drained the break-in oil and re­placed it with Lu­cas Hot

Rod 10w30 that has a higher zinc level and a new fil­ter. This may not be nec­es­sary and Chevro­let doesn’t re­quire it, we did it as a pre­cau­tion to make sure the cam is fully ac­cli­mated to its lifters. Af­ter per­haps an­other 2,000 miles you could switch to a qual­ity off-theshelf API oil, or con­tinue to use high-per­for­mance oil with higher zinc lev­els.

Over­all, our sim­ple en­gine swap was a com­plete suc­cess. The new crate en­gine runs smooth and makes ex­actly the power that we thought it would but is docile and more fun to drive now than our old, balky small­block. The new en­gine will de­liver tens of thou­sands of re­li­able miles, which is ex­actly what we need for our parts chaser. What made the swap much eas­ier was cre­at­ing a check­list of what we needed. And now you have the list too. CHP

01 | Bolt­ing in a new crate en­gine isn’t dif­fi­cult, but it helps to have all the parts and tools. The more pre­pared you are ahead of time, the less ag­gra­va­tion will oc­cur.

02 | Here’s our Good­wrench 350 af­ter we re­moved it from the crate. It showed up at our shop door with no drama, shipped through Sum­mit at no charge. With head­ers and a four-bar­rel in­duc­tion, this en­gine will make al­most 250 hp, which is plenty of power for the daily driver it’s go­ing in.

03 | We yanked the old en­gine (left) but re­al­ized that many of the parts would not trans­fer to the new en­gine. The old en­gine was an ex­ter­nally balanced 383 with Vortec heads.

04 | We in­stalled a new Dor­man bal­ancer us­ing a sim­ple press-on tool from Sum­mit Rac­ing. We al­ways coat the in­side of the bal­ancer and the in­staller threads with an­ti­seize to pre­vent dam­age.

05 | Note how the stock valve cover(right) in­ter­feres with the in­take man­i­fold. The cov­ers can be trimmed to pro­duce the clear­ance. In­stead, we chose a set of cast-alu­minum cov­ers that are re­lieved on the in­board side (left) to clear the in­take.

06 | The starter mo­tor stayed with the pre­vi­ous en­gine so we picked up a re­place­ment from Sum­mit. We chose a 168-tooth flex­plate so that re­quires the starter mo­tor with the off­set bolt holes. The smaller, 153-tooth flex­plates use the starter with the in­line bolt holes. 07 | This photo shows the lit­tle plas­tic plug that blocks the stock dip­stick hole on the pas­sen­ger side of the en­gine.The en­gine comes with a steel plug that must be driven into place with a ham­mer. We used the orig­i­nal dip­stick po­si­tion on the left side of the en­gine.

08 | We’re us­ing an in­ex­pen­sive pres­sure lube tool from Sum­mit but you can make one us­ing an old Chevy dis­trib­u­tor. Just re­move the gear and shaft, cut off the top of the shaft so it will fit into a 1/2-inch drill mo­tor. Then fill the pan with oil, spin the drive clock­wise un­til oil squirts out of all 16 pushrods onto the rock­ers. This might take 5 min­utes or more.

09 | We pre-filled the Fram oil fil­ter with Lu­cas 30w Break-In oil and put the re­main­ing 5 quarts in the en­gine.

10 | The old ra­di­a­tor had been thor­oughly abused, was leak­ing, and had sig­nif­i­cant fin dam­age so we re­placed it with a di­rect-fit, three­core alu­minum Sum­mit ra­di­a­tor. We filled it with a fresh 50/50 mix of an­tifreeze and fil­tered wa­ter to en­sure proper an­ti­cor­ro­sion pro­tec­tion.

11 | The Good­wrench en­gine comes with two dif­fer­ent bolt-on tim­ing tabs in­tended for ei­ther a 7- or 8-inch bal­ancer. We used the tab for the larger bal­ancer and set the ini­tial tim­ing at 12 de­grees BTDC.

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