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Chevy 350 Engine Build - Sleeper Small-Block Combo

Sneak Up And Put 'Em Away With This Sleeper Small-Block Combo

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This is the perfect short-block for your sleeper. It looks like an ordinary Chevy 350, but underneath is a 4.00-inch stroke crank and a sturdy bottom end that is ready to handle dragstrip time, street miles, and some hits from our friend the nitrous bottle. This is intended to be an engine you can do yourself with a common block and would be perfect for a four-door Nova, C10 truck, or wrong-year Chevy wagon. It will look stock and make grunt for some serious street fun.

In this issue, we are going to show you how to assemble the short-block and get it ready for street action. Just for grins, and to get a baseline for future tinkering, we added some iron 2.02 heads and a throwaway manifold and gave it a quick pull on the dyno. We figure there is at least another 100 hp to be had with an intake, carb, and cylinder head swap. We'll show you those parts in future issues. For now, crack a cold one and discover how to massage a 4-inch crank into a 3.48-inch hole.

On The Dyno
The intake and heads are the big cork in this combo, but ultimate power wasn't the point. With this big bottom end, the torque is steady and we should be able to add another 100 to 250 hp with heads, an intake, and a little hidden nitrous system. Check the numbers.*

RPM LB-FT HP
2,500 409 195
2,600 406 201
2,700 404 208
2,800 404 215
2,900 404 223
3,000 407 233
3,100 410 242
3,200 414 252
3,300 415 261
3,400 417 270
3,500 421 280
3,600 426 292
3,700 429 302
3,800 430 311
3,900 429 318
4,000 426 325
4,100 423 330
4,200 418 335
4,300 414 339
4,400 410 343
4,500 405 347
4,600 400 350
4,700 394 353
4,800 387 354
4,900 381 355
5,000 373 355
5,100 366 355
5,200 358 355
5,300 350 353
5,400 341 351
5,500 332 347
*Rounded to the nearest decimal

The Heads
Although this article is primarily about wedging the biggest crank possible into a 350 block, we couldn't resist running it on the dyno. We also wanted to keep this engine as low-buck as possible, so we used a set of iron 882 heads for the baseline. Toki tuned them up with a set of 2.02 intake valves and added a set of what he calls Z28 springs that can handle up to 0.550 lift. Besides being cheap, the springs fit into a standard seat, allowing you to use the factory oil shield and valve seals. Toki thinks it is the best way to control oil.

"You can have a guy with totally shot valveguides and it won't burn oil because the shields are still in place. It is an inexpensive way to control oil without cutting the tip of the valveguide to install Teflon seals." Toki says. For the ignition, we tried the MSD Street Fire HEI. It is basically a good distributor that you don't have to rebuild before use. It comes with vacuum and mechanical advance, adjustable curves, and is pretty with a polished housing and red cap. It already has a built-in coil, so all you have to do is stab it in and connect it to 12 volts.

Cam and Valvetrain
This combo doesn't need anything too crazy in the cam grind to make torque. The grind Toki chose was a mild Comp Cams circle track cam designed for a small, low-compression engine with an iron intake and manifolds. It has 236/238 duration at 0.050 with 0.501/0.501 lift on a 108 LSA. Toki wanted something with less than 240 degrees of intake duration to keep some air velocity and a short lift to use the Z28 valvesprings.

The Potential Downside
When you add Hard Blok to short-fill the water jacket, you get controversy. Jack McInnis from Dart Machinery (which sells aftermarket blocks) says it will overheat, Ted Toki from Westside (which sells parts) says it won't. It is important to understand that there are gambles and payoffs here. For a mild street engine, this works. On a radical race engine that you try to put on the street, you will run into oil cooling issues. We would add an oil temp guage to make sure oil stays below 230 degrees and run a synthetic oil like Mobil 1 to be safe.

If you plan on using this as a mild combo like we are, it should run forever.

Budget Big-Inch Stroker Specs
Bore: 4.030
Stroke: 4.00
Deck: 9.025
Rod: 5.850
Compression height: 1.175

Parts And Prices*
Short-Block
Part PN Source Price
350 block N/A Westside Performance $125.00
Pistons 12347-0.030 Probe $452.17
Rods CRS5850BST Eagle $475.00
Crankshaft 4.00 RPM $495.00
Rod bearings CB663-H King $60.00
Main bearings MS909-H King $105.00
Rings 9901-30 Akerley and Childs $89.90
Total $1,802.07
*Prices are quoted from Westside Performance.
Machine Work
Job Price
Bore and hone block $160.00
Deck block $150.00
Add Hard Blok $80.00
Block prep (clearancing block and pistons) $350.00
Balance rotator $125.00
Total $865.00
Assembled two-bolt block parts and labor $2,583.57
Assembled four-bolt block parts and labor $2,808.57
Other Parts**
Part PN Source Price
Camshaft 12-647-5 Comp Cams $176.39
Complete cylinder heads 882 Westside Performance $800.00
Iron Intake N/A Pick Your Part $29.99
Q-Jet carb N/A Pick Your Part $33.99
Distributor 8362 MSD $143.95
Timing chain 3200 Comp Cams $27.95
Cam lock plate 4605 Comp Cams $2.50
Lifters 812-16 Comp Cams $72.95
Stamp steel rockers 1212-16 Comp Cams $81.95
Pushrods 7.800-inch 7372-16 Comp Cams $92.88
Assembly lube 104 Comp Cams $6.95
Cam and lifter lube 152 Comp Cams $6.95
Oil pump MSSHV Melling $27.95
Z28 valvesprings*** 98214 Competition Products $29.95
**Prices are from Summit Racing.
***Price from Competitionproducts.com
SOURCES
COMP Cams Westside Performance
Los Angeles
CA
Summit Racing
P.O. Box 909
Akron
OH  44309-0909
800-230-3030
www.summitracing.com
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