AFR's New 165cc Renegade Heads - Airflow Redefined

Our non-emissions 165cc heads (PN 1399; $1,560) feature 1.90/1.60-inch valves, fully CNC-ported combustion chambers and ports, 3/8-inch ARP rocker studs, and 5/16-inch pushrod guide plates. We did opt for titanium spring retainers, a $100 option. AFR also milled our heads down, bumping up our compression ratio from stock (about 9.2:1) to 10.25:1. The combustion chambers are usually 58cc on these, but ours are now 50cc. Since these were an all-new design, we wanted to see how they flowed on a flow bench. So we headed to Auto Performance Engines (APE) in Auburndale, Florida. There, Kevin Willis put the new 165s to the test. On a 4.030-inch bore on a Flow Pro bench, they flowed an astonishing 269.4/212.5 cfm at 0.500-inch and 278.5/216.9 cfm (intake/exhaust) at 0.600-inch lift! The intake flows over 200 cfm from 0.300-inch lift and above.

Willis was very surprised, and compared these to a pair of the previous AFR 185s that he tested, which flowed slightly better down low, but were surpassed by the Renegade 165s above 0.400-inch lift. He even had to re-check everything to make sure he did it correctly. For the install, we headed to Lamotta Performance in Longwood, Florida. There, Billy Eldert has been slowly modding Bickam's LX since the late '90s. To establish a baseline, we strapped it to Lamotta's Dynojet chassis dyno. It put down 222 rwhp and 272 lb-ft of torque.

Eldert installed the cam and a new timing chain from Comp Cams. He then mocked up one cylinder head and checked piston-to-valve clearance. Everything checked out, and he finished reinstalling the rest of the components and added five quarts of Comp Cams Muscle Car and Street Rod oil. He also set the timing back to 10 degrees BTDC, where it was when we started.

Back on the chassis dyno, without any additional tuning, Bickam's LX spun the rollers. It made 285 rwhp and 309 lb-ft of torque--a 63hp and 37-lb-ft increase. Eldert then installed an SCT Performance chip with a canned tune from SCT. After making another pull, we were rewarded with 302 rwhp and 325 lb-ft of torque. We picked up 80 rwhp and 53 lb-ft of torque with a heads and cam swap--and we didn't sacrifice any power or torque down low. You actually can have your cake and eat it too, after all.