Report - Edelbrock Thunder AVS

[Buzz]

Initial reaction: VERY impressed!

I finally got tired of the constant tuning and fiddling with recurring hard starting, poor running and plug fouling issues and ditched my second Holley carb. In its place, I took a chance and bolted on a new Edelbrock Thunder AVS with adjustable secondaries. This is not intended to be a knock on Holley carbs, but in my experience with two of them, I would have them running great at times, but it just never lasted very long - the same old issues just kept coming back.

Truthfully, I wasn't sure what to expect, and I'm happy to report the difference is night and day. The car starts instantly, hot or cold and unless its been sitting for more than a day or two, I don't even have to touch the gas pedal. The slightest turn of the key and she fires right up. It feels uncannily like a car with EFI now - squirt gun throttle response and absolutely no bog or hesitation on acceleration from any speed. I've often read that Edelbrocks may run well, but Holleys make more power. I have no way to measure, but possibly due to the improved throttle response, the car actually feels faster now.

Re the recent hot start thread, I began having serious hot start problems with the old holley, so I put louvers in the hood, added a heat shield under the carb and insulated the fuel log and lines from the mechanical pump. Those changes made a huge difference. Still had recurring cold start gremlins, though.

One other little discovery I made was that the big 16 X 3" drop-base air cleaner was shrouding the carb and baking it in hot air on long drives to the point where there was a noticeable drop in performance after a few miles. The hood louvers do a great job venting hot air from the engine compartment, but the big, deep air cleaner was neutralizing their effect. When I switched back to a smaller flat base filter, that problem went away.

The old Holley heat shield won't fit with the Edelbrock carb and its plumbing, and I have not yet insulated the fuel lines but so far there's no sign of any problems. I got a 1/2" phenolic spacer but I am waiting on some longer carb studs before I can do the install. For posterity, I will also add a heat shield when I put on the spacer.

I am very happy with my new carb.