inzane01

Hello, First of all I would like to say this is a great site. Iam new to the site today. Anyway I purchased a 1983 mustang gt last fall and Iam in the process of a total overhaul. So far the motor is bored 40 over I have a rpm cam, rpm heads 190/60 a rpm intake and gear drive. I put the comp gold roller rockers 1.6 ratio and a 80 gph fuel pump, and bbk shorties. I need a little help with the carb edelbrock is telling me to go with the 750 electronic choke. I was just going to put the 600 on. What should I do???????

wowvfast

302 correct?....600-650 is plenty.. I nice 600 dp holley will work great..but it's not a gas mileage carb*L*

mjr46

I ran a 650 dp on a simialar set up and it ran really well , that is tuned properly it ran well

symonds86

where in ny are ya

mjr46

here is something you really need to read if you can view it
http://sbftech.com/index.php/topic,8087.0.html

inzane01

I'am from upstate Hunter NY.

Portmaster

You can ask a 100 differant builders/tuners what best and chances are if they are really good you will get 100 differant opinions. What was good ten years ago isn't all that great today and whats great this year won't be 12 months from now. Carbs get better and better as well as the parts underneath them.

The biggest thing to this mystery is how well can you tune a carb? Where do you want the power? Are you concerned about mpg? Is the car a daily driver? Do you care if you have to sit in the car 5 minutes while the engine warms up?

If you want a Double pumper carb you will have to give up the electric choke (unless you want to invest a huge sum of money) for your car. If you have a car with a 2:73 gear you don't want 950 cfm carb a pair of 50cc pumps squirting it off from a stoplight and you don't want an engine with a huge thumping high duration cam, 4:56 gears and 4500 stall with Vac secondary carb.

Now the RPM Cam for that is mildly agressive with 224/234 degress of duration@.050 and your engine should spin up to 6500 rpm or a little more. It isn't as rpm restricted as a Hyd roller motor because of less valvetrain weight. The heads should allow it to get past 6500 without much problem
on a 308 cubic inch engine even with a 1.90 intake valve.

Now which carb is right for you? I'll give you my opinion depending on what gear ratio you have and assuming you have a manual trasmission and it's a daily driver.

2:73-3:55 Edelbrock Thunder AVS 650 or Holley 670 Street avenger

3:73-4:10 Holley 770 Street Avenger, or Summit (Holley) 750 Vac Sec.

If you don't mind a cold natured car that you have to sit in to get the engine warm. with 3:55-4:10 gear I would go with a Holley 650HP street. Geared any taller and you need better heads.

The older model Holley like the 650dp (4777) don't work near as well as the newer HP series. Even though some carbs have a bigger CFM rating doesn't mean it will make more power or power where you need it. In all out performance a 650HP series Holley will outperform the older 750 cfm (4779) Holley in most situations.

When it comes to carbs it's tuning, tuning ,tuning that makes the differance. For the best overall performance and easist to tune and the most street friendly carb for the novice tuner I would tell you to go with the Holley 670 street avenger on your mildly agressive 308.