AFR currently has three spider assemblies available for their Titan series of small-block Chevy manifolds, including the Titan DPR, a dual-plane street/strip layout, the street/strip TXS single plane, and the TXR high-rise race single-plane. Any of these manifold configurations can be swapped on a common baseplate, and the swap can be completed in just minutes since the baseplate (and distributor) can remain in place on the engine. To aid sealing, The Titan manifolds took a cue from the latest OEM sealing technology and feature molded rubber seals rather than conventional gaskets. These seals fit in precision-molded retention channels in the manifold, and are crush-limited by the fastener configuration for a perfect seal every time. The system virtually eliminates the potential for fuel, vacuum, coolant, or oil leaks.

We had a chance to run all three of the Titan manifold configurations on a 372ci street small-block equipped with AFR street 195cc heads. These three configurations are designed to cover the needs of most conventional small-block Chevy engines, from street to serious race. The dual-plane DPR showed the broadest torque curve while retaining excellent power production into the higher rpm ranges. With the single-plane TXS, we saw the textbook trade in low-end torque for higher rpm output that would be expected when swapping from a single-plane to a dual-plane manifold. This would be the ticket for combinations where top end power trumps low-end torque requirements, such as applications with high-stall torque converters that never see the lower end of the rpm range. The TXR high-rise single-plane is designed for serious engines, and the moderate power of our street/strip engine wasn’t really at a level that would demand an intake of that capacity. Interestingly, the TXR race did show a power gain compared to the smaller TXS, even with our moderate combination. On a serious big-inch small-block, we’d expect even bigger power gains with the TXR.

We did find that the Titan offered unrivaled ease of installation compared to conventional small-block Chevy manifolds. On the dyno, we worked through the three manifold configurations in record time, without the hassle of draining the coolant, or pulling and retiming the distributor. The sealing system performed as expected, without spilling a drop of messy liquid on our stout small-block. We have to hand it to AFR for taking the lead in technology with the Titan, breathing the newest in manifold technology into the familiar small-block.

The Engine

While 372 ci might seem like an unusual combination, the bottom end of our engine is based upon a Dart SHP short-block assembly, offered with a bore and stroke of 4.125 inches and 3.480 inches. Featuring all forged internals, this big-bore, short-stroke combination is virtually bulletproof, and it delivers a compression ratio of 10.5:1 with the AFR 195cc street heads on our motor. Valve action is provided by a COMP 242/248-degree duration at .050 hydraulic roller cam. While the cubes are moderate compared to some of the common longstroke combinations, the power output and willing rpm make this a standout piece.

Dyno Results

AFR Titan Manifolds 373ci small-block Chevy

Torque Horsepower
RPM DPR TXS TXR DPR TXS TXR
3,000 396 385 390 226 229 223
3,200 409 390 396 249 238 241
3,400 435 409 413 282 265 267
3,600 452 425 432 310 291 296
3,800 463 436 445 335 316 322
4,000 475 452 458 362 344 349
4,200 485 462 470 388 370 376
4,400 489 469 477 410 393 400
4,600 489 474 481 428 415 422
4,800 487 476 485 445 435 443
5,000 485 480 488 461 457 465
5,200 484 484 489 479 479 484
5,400 481 483 488 495 497 502
5,600 473 477 480 505 509 512
5,800 465 470 470 513 519 519
6,000 456 461 462 521 527 528
6,200 445 451 453 525 533 535
6,400 431 440 443 525 536 540
6,600 414 427 430 520 537 540

SOURCE
Dart Machinery
353 Oliver Street
Troy
MI  48084
248-362-1188
http://www.dartheads.com
Comp Cams
3406 Democrat Road
Memphis
TN  38118
800-999-0853
http://www.compcams.com
Air Flow Research
28611 W. Industry Drive
Valencia
CA  91355
661-257-8124
http://www.airflowresearch.com
Holley
1801 Russellville Road
Bowling Green
KY  42101
270-781-9741
www.holley.com