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|
What’s it Flow?(cfm at 28 inches H2O)
| RHS Pro Action 225cc Cylinder Heads |
|
0.200 |
0.300 |
0.400 |
0.500 |
0.550 |
0.600 |
| 2.055 intake |
144 |
202 |
254 |
290 |
301 |
313 |
| 1.600 exhaust |
109 |
154 |
187 |
205 |
210 |
214 |
More stuff to make it fit When it comes time to drop this newly possessed powerplant into its new home, we’ll also need a way to connect the modern Gen III engine to the old-school Turbo 400 trans our Chevelle will be running. For this, we sourced TCI for one of its 168-tooth internal balance flexplates. This stout piece is 0.035-inch thicker than stock, and the starter ring is welded to the plate on both sides for increased strength.
Cam Shaft |
| Manufacturer: COMP Cams |
| PN: 54-428-11 |
| Grind Number: XR281HR |
| Type: hydraulic roller |
| Valve lift: 0.571/0.573-inch intake/exhaust |
| Duration at 0.050: 228/230 degrees intake/exhaust |
| Lobe separation: 112 degrees |
| RPM |
LB-FT |
HP |
| 3,000 |
419 |
239 |
| 3,100 |
415 |
245 |
| 3,200 |
415 |
253 |
| 3,300 |
419 |
263 |
| 3,400 |
426 |
276 |
| 3,500 |
432 |
288 |
| 3,600 |
437 |
300 |
| 3,700 |
441 |
311 |
| 3,800 |
445 |
322 |
| 3,900 |
448 |
333 |
| 4,000 |
453 |
345 |
| 4,100 |
455 |
355 |
| 4,200 |
455 |
364 |
| 4,300 |
456 |
373 |
| 4,400 |
458 |
384 |
| 4,500 |
459 |
393 |
| 4,600 |
458 |
401 |
| 4,700 |
457 |
409 |
| 4,800 |
457 |
418 |
| 4,900 |
459 |
428 |
| 5,000 |
460 |
438 |
| 5,100 |
460 |
446 |
| 5,200 |
458 |
454 |
| 5,300 |
456 |
460 |
| 5,400 |
453 |
466 |
| 5,500 |
450 |
471 |
| 5,600 |
445 |
475 |
| 5,700 |
441 |
479 |
| 5,800 |
437 |
483 |
| 5,900 |
433 |
487 |
| 6,000 |
429 |
491 |
| 6,100 |
425 |
493 |
| 6,200 |
419 |
495 |
| 6,300 |
413 |
495 |
| 6,400 |
405 |
493 |
| 6,500 |
397 |
491 |
| Average Torque |
453 |
| Average Power |
409 |
 A comparison of the stock...  A comparison of the stock (left) and RHS intake ports shows the difference between 205 cc and 225 cc of intake runner area in the new heads. RHS’ Kevin Feeney says, the flow numbers are conservative, as the RHS engineers focused more on the quality of the airflow, rather than just quantity. If the air speed is hindered, low-end torque suffers. Based on our numbers, we’d have to say this isn’t a problem with these heads, as our creation has plenty of low-end pull along with gobs of top end power.  The combustion is also much...  The combustion is also much different than the OE chamber. It’s got more of a kidney bean shape, as opposed to the heart-shaped stocker. It’s also designed to “improve airflow and flame propagation”, which leads to increased power and torque. Again, we’d have to say that our numbers bear out the claims. It also bumped the compression up a bit, from 10:1 to 11.41:1—we had to back our timing off by 1 degree, but still made great power on California’s tepid 91-octane gas.  And finally, we outfitted...  And finally, we outfitted our engine with Edelbrock’s latest aluminum ignition coil covers. The factory coils bolt directly to the cover, eliminating the factory bracket. They look great, but this engine still looks better than it runs, which is how it should be. CHP
RHS Pro Action cylinder heads |
| Advance: 32 degrees |
| rpm |
lb-ft |
hp |
| 3,000 |
431 |
246 |
| 3,100 |
427 |
252 |
| 3,200 |
425 |
259 |
| 3,300 |
428 |
269 |
| 3,400 |
436 |
282 |
| 3,500 |
442 |
295 |
| 3,600 |
447 |
306 |
| 3,700 |
450 |
317 |
| 3,800 |
454 |
329 |
| 3,900 |
460 |
341 |
| 4,000 |
465 |
354 |
| 4,100 |
467 |
365 |
| 4,200 |
468 |
374 |
| 4,300 |
469 |
384 |
| 4,400 |
470 |
394 |
| 4,500 |
470 |
403 |
| 4,600 |
470 |
412 |
| 4,700 |
471 |
421 |
| 4,800 |
472 |
432 |
| 4,900 |
474 |
443 |
| 5,000 |
476 |
453 |
| 5,100 |
476 |
462 |
| 5,200 |
475 |
470 |
| 5,300 |
472 |
477 |
| 5,400 |
470 |
483 |
| 5,500 |
466 |
489 |
| 5,600 |
463 |
494 |
| 5,700 |
460 |
499 |
| 5,800 |
458 |
505 |
| 5,900 |
455 |
511 |
| 6,000 |
451 |
516 |
| 6,100 |
446 |
518 |
| 6,200 |
441 |
520 |
| 6,300 |
435 |
521 |
| 6,400 |
428 |
521 |
| 6,500 |
421 |
521 |
| Average Torque |
468 |
| Average Power |
424 |
|