35 Cafe Racer w 502's - which heads to go with?
01-17-2026 | 11:18 AM
#21
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From: BC
A 502 (4.47" bore x 4" stroke) at 5800 has a requirement of a 2.67" intake port CSA (cross sectional area)
AFR 265 CSA is 2.64" sq.
AFR 265 heads would be a perfect application. Would likely support up to 6000rpm with no port choking. At these higher port velocities...port shape has more influence on when the ports begins to sonically choke off.
2.19" valves are more than sufficient for the job. It's no so much the valve head dia...but the valve throat in the head that determines flow potential. Generally a max 91% throat dia for well setup valvejob/bowl etc.
Big CID high rpm engine for drag racing etc. Require much larger ports and valve sizes.
AFR 265 CSA is 2.64" sq.
AFR 265 heads would be a perfect application. Would likely support up to 6000rpm with no port choking. At these higher port velocities...port shape has more influence on when the ports begins to sonically choke off.
2.19" valves are more than sufficient for the job. It's no so much the valve head dia...but the valve throat in the head that determines flow potential. Generally a max 91% throat dia for well setup valvejob/bowl etc.
Big CID high rpm engine for drag racing etc. Require much larger ports and valve sizes.
