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I found some 492 heads for sale locally. Will these be a direct swap onto my 1975 L48? Wil the EGR valve still work or are there no ports for that on these heads? These heads are bare castings so I'll need to get valves, rockers, and springs.. will the swap be worth the performance increase or is it minimal?
The double hump heads are very good. BUT it depends what you have to pay for those bare heads, Plus cleanup, crack checking, and parts to get the head ready for installation.
492 Yes, direct swap. Yes, has exhaust riser. Yes, EGR ...
... But with purchase cost, then paying a shop to rebuild-assemble heads ... you may be close to better-performing heads' cost.
If I didn't require EGR ... they've become hard to find, but good used L98 aka ZZ4 heads ... aluminum w/ 58cc chambers.
If I didn't require EGR ... I'd also be looking for good used Vortecs iron 64cc & a cheap used intake.
EQ aka EngineQuest makes a very good & affordable "hybrid" iron head with heat riser & great Vortec fastburn 64cc chamber ...
... fits conventional intake ... pn CH350H bare or CH350HA assembled. CoO New Zealand.
they're advertised as having the 2.02 valves with screw in studs and hardened seats. $300.00 for the pair. I think I may let them go and keep looking.
Thanks