Vacuum or Mechanical Secondaries?

[pauls340]

Which is better for street cruising? Mild 340, 4 spd, electronic ign, stock intake and exhaust. Thanks

 

[Blownfish]

Vacuum is definitely better for a mild street cruiser, especially with a 4 gear.

 

[hellion_locdogg]

I would just follow Holley's carb rec on their site.

,Cliff

 

[65Vart]

Which is better for street cruising? Mild 340, 4 spd, electronic ign, stock intake and exhaust. Thanks

Vacuum for the street unless you are racing it. With the 4 spd I would go mechanical if it sees any track time at all.

 

[green1]

Vac, don't add the proverbial screw to hear the secondarys come in.

 

[dusterny]

Vac secondry works good for street IMO.

 

[Demon 408]

I read your other post about your TQ: http://www.forabodiesonly.com/mopar/showthread.php?t=110812

I think your best bet, based on your other post, is to learn how to adjust your TQ. I have had both the Holley and TQ, and for your application the TQ will get you what you want. You've already spent the money having it professionally rebuilt, so use it.

Buy this book: [ame="http://www.amazon.com/Carter-Carburetors-Dave-Emanuel/dp/0931472113/ref=sr_1_sc_1?ie=UTF8&qid=1282171044&sr=1-1-spell"]Amazon.com: Carter Carburetors (9780931472114): Dave Emanuel: Books@@AMEPARAM@@http://ecx.images-amazon.com/images/I/61D9R06EEHL.@@AMEPARAM@@61D9R06EEHL[/ame]

Go to this site and read: http://www.thermoquads.com/

And, go to this site and read: http://www.carburetor.ca/Tech/Carter/tqguide-Vaanth.html

Buy this tool: http://www.dynoroomtools.com/Thermoquad_Air_Door_Adjusting_T.html
or learn how to use two screw drivers to adjust your air door opening.

If you don't want your TQ send it to me..please! I'll even pay the shipping. PM me for my shipping address. :cheers:

 

[skep419]

I went with the holley street hp mechanical. Works great

 

[turbodart68]

Mechanical for a 4 speed car. Vacuum carbs take too long, even with the lightest spring, for a 4 speed car since you cycle the throttle closed when you shift. It would be a pig if you had to wait for the secondaries to open after every shift.

 

[the67fish]

If its a Holley the general rule of thumb for a stick shift is the vacuum secondaries cause once you floor it you dont lift (racing).

 

[pauls340]

If i'm never going to do any racing, doesn't it make sense to have mechanical ?

 

[dgc333]

The difference between a well tuned mechanical and a well tune vacuum secondary carb is only going to be a .1 or two. The vacuum secondary is going to be easier to set up for a novice, is more tolerant to being oversize and will give you better mileage.

For a street driven car there is really no reason to use mechanical secondary carb. Get a Holley 670 Street Avenger or an Edelbrock 650 or sort out the carb you have.

 

[turbodart68]

If i'm never going to do any racing, doesn't it make sense to have mechanical ?

In a word, YES. A mechanical secondary will have better throttle response when tuned properly. If your 340 is stock a 700 dp from holley will put a smile on your face for sure. Go get one and lay some rubber!