Building the Perfect Combination

Building the Perfect Combination

Everyone has heard it a thousand times - BUT IT IS TRUE!! A car with a group of parts that compliment each other will run better than a car with a mismatch of parts. This group of parts is called the combination. This article is designed to help you build the perfect combination. A well thought-out combination will not only make your car more enjoyable but also enhance the drivability and acceleration.

How to Use This Document:

1) Choose how you intend to use your car -> Is it going to be a daily driver? Used only on weekends for cruising? Or an all out race car? This is your most important choice. It will set the foundation for all future selections. Choose from the following:

Power Level #2 RV and Commuter -> Good fuel economy, medium towing, improved mid-range performance for everyday use. No internal mods are required. Smooth idle; expect idle speeds of 850 rpm or less. Power range from 1,000 to 4,000 rpm; peak horsepower around 5,000 rpm.

Power Level #3 Mileage and Power -> Daily driver, mild performance rebuilds, some towing. Slight lope to idle; expect idle speeds of 900 rpm or less. Power range from 1,400 to 4,400 rpm; peak horsepower around 5,400 rpm.

Power Level #4 Street Performance -> Good upper mid-range performance for street machines. Works well for medium and heavy towing. Small lope at idle; expect idle speeds of 950 rpm or less. Power range from 1,800 to 4,800 rpm; peak horsepower around 5,800 rpm.

Power Level #5 Hot Street Performance -> Edge of daily driver street cars. Best left for weekend cruise cars. Has a lope at idle; expect idle speeds of 1,000 rpm or less. Power range from 2,200 to 5,200 rpm; peak horsepower around 6,200 rpm.

Power Level #6 Street / Strip -> Edge of streetability. Mild bracket racing. Has a rough idle; expect idle speeds of 1,100 rpm or less. Power range from 2,600 to 5,600 rpm; peak horsepower around 6,600 rpm.

Power Level #7 Competition -> All out race engine. Not intended for street use. Idle will be very rough; expect idle speeds of 1,100 rpm or more. Power range from 3,000+ rpm; peak horsepower around 7,000+ rpm.

2) Now let's have a reality check on the above choice. Most people have some type of estimated 1/4 or 1/8 mile drag time they want to run. Some are happy with the 14s, some want 12s, or even others think it's not worth driving unless it can hit the 11s ;-} Use the chart below to decide on how much horsepower it will take to get to your goal.

ET & SPEED(seconds @ mph)

VEHICLE WEIGHT
(pounds)

2400

2600

2800

3000

3200

3400

3600

3800

4000

4200

16.0 @ 85

116

125

135

145

154

164

174

183

193

203

15.5 @ 88

127

138

149

159

170

180

191

202

212

223

15.0 @ 91

141

152

164

176

187

199

211

223

234

246

14.5 @ 94

156

169

182

194

207

220

233

246

259

272

14.0 @ 97

173

187

202

216

230

245

259

274

288

303

13.5 @ 101

193

209

225

241

257

273

289

305

321

337

13.0 @ 105

216

234

252

270

288

306

324

342

360

378

12.5 @ 109

243

263

283

304

324

344

364

385

405

425

12.0 @ 114

275

297

320

343

366

389

412

435

458

480

11.5 @ 119

312

338

364

390

416

442

468

494

520

546

11.0 @ 124

356

386

416

445

475

505

535

564

594

624

10.5 @ 130

410

444

478

512

546

580

615

649

683

717

10.0 @ 136

474

514

553

593

632

672

712

751

791

830

9.5 @ 143

553

599

645

692

738

784

830

876

922

968

9.0 @ 151

651

705

759

813

868

922

976

1,030

1,084

1,139

8.5 @ 160

772

837

901

965

1,030

1,094

1,159

1,223

1,287

1,352

8.0 @ 170

926

1,004

1,081

1,158

1,235

1,312

1,390

1,467

1,544

1,621

For those with no interest in drag racing :-{ This will give you an idea of how fast you could run with your combination.

3) Divide the horsepower required by the number of cubic inches of your motor. This should correspond to the estimated HP / CID chart below.

Power Level Horsepower / CID Range
1 0.5 to 0.7
2 0.6 to 0.8
3 0.7 to 0.9
4 0.8 to 1.1
5 0.9 to 1.2
6 1.1 to 1.5
7 1.5 to 2.0

If the calculated number does not fall into the range given, then the combination needs to be rethought. Either change the car weight, revisit how the vehicle will be used, or expect a different ET (NOTE: It is always better to remove weight than to add horsepower to get to your intended ET. Removing weight reduces stress and parts breakage. Adding horsepower will increase stress and parts breakage.) Remember, it is impossible to get a car to run in the 11s and expect it to be a mild mannered, smooth idling daily driver. Hold to the intended application suggestions in #1 and you will be much more satisfied in the long run.

4) Once the Horsepower per CID requirement has been satisfied, you can select the parts for your combination. Below is a list of suggested parts for a 260 - 351 cubic inch small block Ford. Other engine sizes will change these selections somewhat. Basically, smaller engines will make less torque and become unstreetable faster as the power levels are increased. Larger engines will be able to step up to the next combination level without losing too much streetability.

VERY IMPORTANT - Do not vary from the set combinations. A stock motor with a pro-street cam or a 2 bbl pro-street engine does not make for a very efficient use of time or money. If you do not understand the point of using these combinations, then you just won't get the meaning of this article until it is too late (you'll learn the hard way!)

See Parts list for building the Perfect Combination

5) One last note -> The right combination is more than just a good engine. The entire vehicle must be taken in to account. A car that doesn't run in the intended operating RPM range, due to improper gear ratio or tire size, will not reach it's full potential. It could even be a dog to drive if the car is always below the power range (read: severe loss of torque; vacuum; drivability; etc..) Select the proper ignition, exhaust, transmission, converter stall speed, gear ratio, tire height, and chassis stiffening to be truly happy with your ride. HINT: many of the other tech articles, downloads, and links on this web site will help.

I hope this helps you to build that combination that makes all your dreams come true. ENJOY!!



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