That's because, like the Q-jet, the Edelbrock's fuel bowl is in the body of the carb, where it's closer to the intake manifold heat. Holley's bowls hang out in the breeze.

 

I love the 'Brock for its ease of adjustment, but the bowl location and lack of fine tuning is its weakest point.....Now, the Holley is great for a all out race jockey, but a bit much for your average garage mechanic to maintain and tune. Im stuck with the brock for now, I may just go back to a Holley simply because they run so much better when things get hot...but dogdam they take forever to tune in.