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Chevy Small Block Testing - Legendary Small-Block Shootout

We Pit The DZ302 Vs L76 327 Vs LT-1 350 In A No-Holds-Barred, Dyno Dogfight.

By Richard Holdener, Photography by Richard Holdener

Given we had not one but three impressive small blocks to test (actually four counting the low-compression LT-1), we fully expected there to be a few issues and true to form, this dyno session was not without its incidents. The first issue occurred when we brought the finished 461 heads to the airflow bench. What we thought was a set of untouched, factory castings with a fresh valve job was actually a ported set. With no replacement set of 461s at our disposal, we opted to run the 327 with the same set of 186s used on the 302. Given the similarities in airflow between a set of 461s and 186s, this was an accurate representation of the true power of the 327.

Next up was the intake manifold, The author purchased the required intake via E-bay but the intake was actually for a 1963 L76 and not the later (and higher HP) 1965 L76. The difference was that the 1963 version was equipped with a Carter carburetor and not the more desirable (and available for our dyno session) Holley carb.

With time running out, we opted to run all three small blocks with the 1970 LT-1 Z/28 intake. Correct for the LT-1 and as-near spot on (in terms of performance) for the DZ302, the intake was actually slightly better than the original manifold for the L76. We'll run a back-to-back test on the two intakes to clear up this issue and provide the results for the interested parties, but know that the L76 might be up slightly from where it would be with the stock manifold.

Naturally the stock exhaust manifolds would kill some of the power compared to the long-tube headers, but the factory tested them with open headers in the late-'60s and early-'70s (SAE gross) so we were comfortable with this (especially since all of the test engines were run in the same configuration.

When we test the stock L76 intake, maybe we'll toss on a set of stock manifolds just to see what the headers were worth. Let's hit the dyno and find out which combo is king.

HORSEPOWER NUMBERS
RPM 302 327 350 350 ('71)
3000 167 196 208 199
3300 184 210 232 223
3500 206 232 254 246
3800 233 261 283 275
4000 248 275 298 291
4300 272 297 318 311
4500 283 308 329 324
4800 301 324 341 340
5000 311 333 347 347
5300 326 344 352 355
5500 333 349 353 361
5800 347 347 350 362
6000 350 348 348 361
6300 353 352 348 353
6500 356 347 342 345
6800 356 339 329 332
7000 352 331 312 319
TORQUE NUMBERS
RPM 302 327 350 350 ('71)
3000 292 332 364 349
3300 293 334 369 354
3500 309 348 381 369
3800 322 360 391 379
4000 325 362 391 382
4300 332 363 389 380
4500 331 360 383 378
4800 329 355 373 372
5000 327 350 364 364
5300 323 341 349 352
5500 318 333 337 345
5800 314 314 317 328
6000 307 305 305 316
6300 295 293 290 295
6500 287 281 277 279
6800 275 262 254 257
7000 264 248 234 239
AIRFLOW DATA CFM:
In/Ex In/Ex In/Ex In/Ex
Lift 186 *461 492 487
.050 30/20 30/21 30/22 31/22
.100 58/45 59/46 59/47 59/51
.200 113/87 115/93 115/92 119/102
.300 158/120 164/127 158/117 173/133
.400 190/136 201/155 186/127 207/144
.500 205/140 211/168 200/134 213/146
.600 205/141 212/174 209/137 215/146

*461 heads eliminated for test due to obvious porting; 327 was run with 186 heads.

SOURCES
Coast High Performance
1650 W. 228th St.
Torrance
CA  90501
310-784-2977
www.coasthigh.com
Holley/Hooker
1801 Russellville Rd.
Bowling Green
KY  42101
2-70/-782-2900
www.holley.com
COMP Cams Pony Carburetors
315-662-3003
Crower Cams
San Diego
CA
619-661-6477
www.crower.com
Pro Comp Electronics
605 S. Milliken Ave., Ste. A
Ontario
CA  91761
9-09/-605-1123
www.procompelectronics.com
L&R Automotive
13731 Bora Dr.
Sante Fe Springs
CA  90670
5-62/-802-0443
www.lnrengine.com
By Richard Holdener
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