I just have a few questions about some carbs, the differences between them mostly.
edelbrock/holly
mechanical/vacume secondaries
Any ideas what the good and bad points are on these 2, and posibly how they work (or maybe a page the explanes this)?
I'm sure the answers are fairly simple but I'm just starting to get into this, Thanks. :hail:

 

i have read somewere, that vacc. secondarys are better for automatic transmissions and mech. sec's for manual trannys,
in my experience, i had a rochester, vacc, sec, on my 350 5-speed camaro and it was good, now i have the edelbrock 1406, 600cfm mech secondarys and it feels that i have twice the power, but i can also tell that after opening and TRY to tune my old rochester 50,000 times already and never felt as good as the edel. 1406, wich i've already opened once (to clean) and it is SO simple i love it.
last but not least, the holleys i've read that they are better if you wanna race (say slightly better than edelbrocks on performance) but it comes with respective increase on fuel consumption (gourmande). never try'd myself, but i never knew of anybody trying it and ditching it to garbage.
Fernando.

 

Check this thread https://www.thirdgen.org/techbb2/sho...readid=101910.

Same basic question and a little more detailed answer.

 

Mig 29,

How do you find your gas consumption withe the Edelbrock 1406 compared to the QJet? I find my 1406 is a gas gobbler, with a capital G!

 

first i've found it GOURMANDE (french for eats like hell) i used to get little less than 400kms out of the rochester, from a full tank.
now with the 1406 barely passed the 250kms mark, but i've found also that the choke was inop. when i did test it, was ok, but after that surprise found out that it was closed all the time, so i'm getting a new choke. (a kinda' intermitent fault)
as it was anyway the performance was like going from flying a cessna 150 to a Mig-29, just unvelievable.
presently i'm changing seals on my diff so with the new choke i'll monitor again the consumption and i'll keep you posted, i'd really like to compare notes with you and all the fellas who have this carb installed, by the way my diff is 3:42.
so let's keep in touch brother.
Fernando.

 

Mig-29,

Ok, my measurements are as follows:

QJet on my 305=17 to 18 mpg in town.

Edelbrock 1406=12 mpg in town.

Man, I can't afford this carb if I can't get a lot better mileage out of it!!!

 

Tw-tw-tw-twelve miles to the gallon?
Is this normal for a carbed 305?

I'm going with a Holley 600 DP on my 305 with a T-5. Can I expect the same mileage?

 

I just got a new 305, and picked up a 600 cfm edelbrock that hasn't moved in 6 months. Right now with the stock q-jet i'm geting about 6 mpg without gunning it to often (still trying to break in) so if i can get 12 from the edelbrock i'd be happy as hell. I havn't tryed the edelbrock i picked up yet, i want to clean it up alittle and try to figure out how the thing works a little better before i stick it on.

 

Thanks, got a little more info any idea if the stock q-jets are vacume or mechanicul? My seconds aren't opening but i've heard that the choke stops them from opening. You heard that any where?

 

Go to the Tech Article section and read the QJet article. It explains just how to set up a QJet for great performance.

The secondaries are vacuum controlled on every QJet.

 

I have had a holley and a Q-jet on my other car. I have had a different intake manifold with the holley, but I did get better gas miliage with the q-jet and a dual palne set-up. The Holley and a high rise got good power but bad gas miliage. Q-jet 20 highway Holley 14. As far as city driving if I could have kept my foot out of the gas the holley would have gotten about 8-10. The q-jet would get around 12 or so. I do have low gears in the car. Q jet +gas -tuning. Holley + power, tuning, -gas. Most Q-jets have a secondary choke, but I modded mine, I hate to be restricted!!

 

what i'm gonna do is re-jet for economy my 1406, to be precise, i'll do it with the table shown on the edelbrock page, is pretty simple to get the numbers, for example i decided to do the step 5 wich meand 1 step down on consumption, basically all i need is 2 jets .092 and 2 rods.
i suggest you try that also dear friend sitting bull, but first look at that table and see what you think
Fernando.