who is are holley experts? I got a 780 question

[oldsman71]

Re: who is are holley experts? I got a 780 question

Thanks for the help guys!!! I guess I got to order some
stuff this next paycheck :D $41.00 from summit thanks Scott!

[squirrel]

Re: who is are holley experts? I got a 780 question

I assume it's right, just passing along the credit where due

[Scott Liggett]

Re: who is are holley experts? I got a 780 question

http://www.summitracing.com/parts/HLY-34-13/

if Scott's part number is right

No faith............

[squirrel]

Re: who is are holley experts? I got a 780 question

http://www.summitracing.com/parts/HLY-34-13/

if Scott's part number is right

[oldsman71]

Re: who is are holley experts? I got a 780 question

thanks alot for the replys guys, anyone know who (jegs, summit, ect ect)

sells that metering block kit or can I get it directly from holley?

the primary block, that they were useing on the rear, has the #7089 & #1601

on it.

[A/Fuel]

Re: who is are holley experts? I got a 780 question

I have done this quite a few times, and have two of them right now. You can use either type of metering block, and they make a solid plug style power valve that fills the hole nicely. You'll have to use four primary side float bowl screws too.

[Mr4Speed]

Re: who is are holley experts? I got a 780 question

I'm pretty sure that the conversion rear blocks don't use a power valve. The metering blocks usually have a list number stamped in them-see if it does and you can tell what it's off of.

[Scott Liggett]

Re: who is are holley experts? I got a 780 question

Holley sells a conversion kit to remove the metering plate on 3310's and add the metering block. Part #34-13 for the 3310.

If the metering block on the rear of that 780 has a power valve hole, it's a primary metering block someone added. The idle screws have me thinking that.

[oldsman71]

Re: who is are holley experts? I got a 780 question

I just took the back bowl off they tryed to run it
with NO power valve :P i bet it ran real good!!!!
there is no room on the main body for the power valve
(just flat, missing the recess) so you have to use the metering plate
for sure!!

[oldsman71]

Re: who is are holley experts? I got a 780 question

I think the early versions of that carb were marketed as a 780 even though they all flow the same. I don't know if the primary block would work in the rear but I doubt it, and I wouldn't mess with it. I have a stock metering plate for it you can have to get it going, and you can still buy the rear metering block conversion kit for it-they used to be pretty cheap, don't know now. I have some extra parts for those down at the shop-I'll see what I have and call you next time I'm down there. I love those carbs-you can make them work on almost anything pretty well.

thanks kris Ill call you soon, thanks to Ron also

[Ron Ward]

Re: who is are holley experts? I got a 780 question

3310 (with no dash number) and 3310-1 are the 780's. The 780 carbs also feature drop-leg boosters. I have two of 'em in the garage.

I just tried uploading some pics showing the difference between straight-leg and drop-leg boosters and my photobucket account is doing goofy stuff... alas, no pics.

The 3310-1 is pretty much the same as the 3310 but it has a large vacuum port (for power brakes) on the base plate.


Ron

edit: I suppose the front metering block would work on the rear, but remember, the front block has idle mixture screws. The rear of your base plate won't be machined to make use of the idle mixture feature on the rear, so you will need to block off the idle mixture passages in the metering block.

I like the 780 series carb for the simple reason of added adjustability with a secondary power valve and secondary jetting. I used to NOT like Holley carbs until I got ahold of one of the 780's.

[Mr4Speed]

Re: who is are holley experts? I got a 780 question

I think the early versions of that carb were marketed as a 780 even though they all flow the same. I don't know if the primary block would work in the rear but I doubt it, and I wouldn't mess with it. I have a stock metering plate for it you can have to get it going, and you can still buy the rear metering block conversion kit for it-they used to be pretty cheap, don't know now. I have some extra parts for those down at the shop-I'll see what I have and call you next time I'm down there. I love those carbs-you can make them work on almost anything pretty well.

[oldsman71]

Re: who is are holley experts? I got a 780 question

will it work with the front primary block in the back?
what would the 780 have had? will this do weird
stuff or give me a more versetile carb?
thanks Jim and Kris , I like to start with an unmolested
core but times are tough.

[Mr4Speed]

Re: who is are holley experts? I got a 780 question

Somebody pieced that together. 3310-3 is the third version of the common 750/780 vacuum secondary carb. It would have originally had a metering plate in the back with fixed jetting, instead of a metering block that accepts screw in jets, and the vac. secondary carbs never had a rear idle circuit. Sounds like someone may have stuck a primary block on the rear.

[squirrel]

Re: who is are holley experts? I got a 780 question

72 jets in front with a 65 power valve, 134-21 metering plate originally in back, it's a 750 cfm not 780.