Carb intake manifold question

[tekno62]

when I replace my old carb with a new Edelbrock 1406 should I also replace the intake manifold

[El Jay]

Why?

[tekno62]

no idea. I would like to get a little better gas mileage and Im going to get a new Edelbrock in hopes that it will help and was wondering if I should do something with the intake manifold at that time.

[Rollie396]

Shouldn't be any need of replacing the intake.The new carb is a square bore style though,so if your intake is the stock spreadbore style,you will need to get the adapter plate with the carb.

[spinning wheels]

Originally Posted by tekno62

when I replace my old carb with a new Edelbrock 1406 should I also replace the intake manifold

Just to make it clear. You have a V8, that had a 4 barrel carb. Right?

I didn't change my manifold when I installed my 1406. I did need to add the adaptor plate, as it has been pointed out. The factory manifold is designed for a spreadbore carb.

[tekno62]

yea - I have a 350 with a 4 barrel - its all stock.

Originally Posted by spinning wheels

Just to make it clear. You have a V8, that had a 4 barrel carb. Right?

I didn't change my manifold when I installed my 1406. I did need to add the adaptor plate, as it has been pointed out. The factory manifold is designed for a spreadbore carb.

[lax54650]

many have claimed the quadrajet gets better mpg. because it has smaller primaries. might be worth having it rebuilt by a qualified guy if mpg is what you are after. jmo

[Beatcoaster]

If you are already buying a 1406 why not get a new intake for another $150? I would think the mpg would be slightly better from it's design, you will be getting a freer flowing design, thanks to 40 years of flow engineering, which will yield a better a/f ratio in the chamber and give you a small bump in hp based on this also. After that, if you don't have them already, get some headers and a new exhaust to free up the gases trying to escape. If you want to go crazy, then get some new cams/heads and tailor those to hp, and/or mpg.....oh and an HEI...

This will be my route of upgrading my 307, until I am ready for a 383 swap...

[prostreetC-10]

[QUOTE=Beatcoaster;3228463]If you are already buying a 1406 why not get a new intake for another $150?
QUOTE]

Intakes basically don't have wearing parts so pick one up off your local craigslist for $40 to $50 bucks!! Used work the same as new when it comes to intakes.

[leddzepp]

If you are looking to get better mileage, why not get a 2-barrel carb? The mileage difference between a Quadrajet and an Edelbrock is negligible, they are both 4 barrels. The money you spend on that new Edelbrock will not offset your gasoline bill enough to justify what you pay for it.

[mr48chev]

Originally Posted by leddzepp

If you are looking to get better mileage, why not get a 2-barrel carb? The mileage difference between a Quadrajet and an Edelbrock is negligible, they are both 4 barrels. The money you spend on that new Edelbrock will not offset your gasoline bill enough to justify what you pay for it.

From past experiences you won't make noticeable mpg gains by dropping back to a two barrel on these engines. You will loose a lot of performance when trying to pass someone.

I think what most of the guys are trying to say is that it will run good with the stock intake and adapter but all around performance should be a bit better running the Performer intake that matches the carb. and as my 200 mile down the road neighbor mentioned Intakes don't have to be new. Usually a guy can find one for about half of new or less on Craigslist or in the local little nickle paper.
I run a performer on my truck and really like it I feel that it gives me that low/mid range boost just where I need it with my truck.

How well you do the total tune and how good a shape everything is in will determine gas mileage along with how heavy your right foot is but these trucks are not noted for getting what would be considered good gas mileage.
For most of us running a 67/72 with a 350/350 15mpg would be just cause for bragging rights. Right now I get 11/12 down hill with a tail wind.

[leddzepp]

I have run both 2 and 4 barrel carbs. The mileage difference is very noticeable, compared to that between a Q-Jet and an Edelbrock... but yes, your performance will suffer. I personally would not run a 2 barrel carb, but if someone is looking to get better mileage it is a viable option. More than anything else, how you drive will determine how good your mileage is.

[spinning wheels]

To improve your gas milage, a lot of little things you do can boost your milage. From taking it easy on the gas pedal, to properly inflated tires.
A new manifold might increase your milage, but not in big numbers. One of the best upgrades, would be to change your cam. Cam designs have come a long way in recent years. Unfortunately, the cam manufactures are spending their money on roller cams. However you can still find a good cam for a SBC.
If you are installing the Edelbrock 1406, look at Edelbrock's packages and see what cam specs they recomend. Edelbrock spends a lot of their money making sure their stuff works well together.

This is always the problem when you start making changes. Trying to change spark plugs can lead to new heads and before you know it, you installed a big block with a 871 blower. Its madness I tell you.... Madness.

Good luck!

[tekno62]

I love madness....

thanks for all the info.

Originally Posted by spinning wheels

To improve your gas milage, a lot of little things you do can boost your milage. From taking it easy on the gas pedal, to properly inflated tires.
A new manifold might increase your milage, but not in big numbers. One of the best upgrades, would be to change your cam. Cam designs have come a long way in recent years. Unfortunately, the cam manufactures are spending their money on roller cams. However you can still find a good cam for a SBC.
If you are installing the Edelbrock 1406, look at Edelbrock's packages and see what cam specs they recomend. Edelbrock spends a lot of their money making sure their stuff works well together.

This is always the problem when you start making changes. Trying to change spark plugs can lead to new heads and before you know it, you installed a big block with a 871 blower. Its madness I tell you.... Madness.

Good luck!