I run a Isky E-75 in a otherwise stone stock 361 Bog Block with Headers, and a 3-Inch exhaust.. I run a four speed and 2.76:1 gears, and it my family/daily driver:
Cam Specs:
Advertised Duration: 320-Degrees
Duration @.050": 274-Degrees
Lift @ Valve: .570"
Lobe Separation: 108-Degree
The car is...
Yeah its normal... I run 302 heads on a 273 and I noticed the same issue with my heads when I got them as cores. I would take them to a machine shop first and have them do a 80-degree (I hope that's right) bowl cut along with a rough cut valve job before you port. That ways you don't cut to...
This bothers me in a way, I always hear everyone knock 273's for not being able to run.. Here's my just of my combo, it runs mid 7 seconds in the eight mile, and I drive it about a thousand miles or so every month.
-Block Bored .060"
-Stock replacement Badger (discontinued) .060 oversize 10.5:1...