edelbrock carbs

[benno440]

i am running 2 edelbrock performer 500 cfm on my 505.

i see edelbrock does the edelbrock AVS thunder carbs #1804 which are calibrated for dual quads, (performers dont have this option)
and when i look at the specs between the 2 i.e metering rods, jets, etc. they are drastically different
for example:
Performer: Metering Jets - Primary .086, Secondary .095; Metering Rods - .065 x .052; Step-Up Spring - orange (5" Hg).

Thunder AVS ( dual quad calibrated ): Metering Jets - Primary .086, Secondary .077; Metering Rods - .065 x .057; #1804: Primary .086, Secondary .077; Metering Rods - .065 x .052; Step-Up Spring - orange (5" Hg).


see the metering rods and secondary jets are a fair bit difference,

could this be some of the reason i have been having tuning issues? would it be better to get rid of the performers and get 2 thunders?

 

[Meep-Meep]

You are comparing apples to oranges. The primary side is similar on both carbs but the secondary air valves are completely different. Also it's possible the thunder carb has a different secondary metering system and that may call for a different size jet. I know the original AVS from like 69 uses dump tubes instead of the AFB style venturi.

 

[benno440]

You are comparing apples to oranges. The primary side is similar on both carbs but the secondary air valves are completely different. Also it's possible the thunder carb has a different secondary metering system and that may call for a different size jet. I know the original AVS from like 69 uses dump tubes instead of the AFB style venturi.

it just got me thinking because of how different they are and that the avs says it is tuned for dual quad situations, so was not sure if i am running 2 carbs that should not be run together.

 

[Meep-Meep]

There is nothing wrong with two AFB's. It's been done for many years on all kinds of factory cars so I wouldn't give up on them.

 

[benno440]

sort of proud of myyself too, i was reading diamondback engines white pages and followed the instructions on how to deburr and polish all the edges in the 2 edelbrocks.
nice smooth transition for the air to get into them now, i cant believe how crappy the casting is on them, also had to deburr my 2" carb spacers massive lip on them.

i think i will have to try a 4 hole spacer instead of an open spacer as the car has gained a bog when you plant it since i put the spacers on. yet i was told by diamondback engines and read an article of people saying to use open spacers to increase plenum volume as these big strokers like the extra air.

 

[lewtot184]

if you read the edelbrock "fine print" through out their catalog you'll notice that those small carbs seem to be calibrated for the small engine dual quad package. i vote two 750's and don't look back.

 

[ykf7b0]

I vote two Holley's if that is an option for you.