Quote:
Originally Posted by Ed Wright
To answer one of your questions Gary, some of the reasons late EFI engines make more power than older engines are the cylinder heads. Improved air flow and improved detonation control allowing higher compression ratios on low octane fuel with out detonation.
The '96 / '00 Vortec trucks heads are so popular on older engines that Edelbrock makes a 4 bl carb intake manifold for them. The ports are high enough a regular carb intake doesn't even cover them. You understand what raised intake ports do, right? :-)
Those Vortec heads make more power than earlier (even "camel hump") heads.
The reason for EFI in late model vehicles is simply emissions and fuel economy.
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Hi Ed,
Our current EFI combo was first dynoed with the carb and intake off of our current carb combo. (750 q-jet and victor -E). After breaking it in we put the big stuff EFI system and related hardware on.....It lost 15 HP... The reason is the little throttle body that comes on our combo. If we were bracket racers and could change the throttle body , then the power would swing over to a plus for the EFI. But like you say ...Its all about airflow (and of course, compression ). Being able to manipulate all the fuel and spark management gives the engine's a wake up call, but how much varies widely from engine to engine depending how out in left field you were in the first place.