Here's my setup. 355, vortec heads, hooker headers(shorties), edelbrock performer rpm intake, comp cams 284h( 240/246 @.05, .507/.510 lift), holley 600 carb with vac secondaries. Oh and flat top pistons. My question is how much slower am I going to be in the 1/4 mile if Im using my current 600cfm as opposed to a 750cfm? I know that my combo would be best suited with the 750 but Im just wondering how much of a difference its going to make between the two carbs if they are both properly tuned.

 

Is this a track only car or is most of the driving on the street ? And whats your stall and gear at ?

 

I agree with above statement

Also

What intake is on it?

I would recomend 750 double pumper for more track then street or 600 vacum sec for street/strip

 

Sorry forgot those. Well its mostly a street car but will see some weekend test n tune and as soon as I get everything set up and tuned I plan on doing some bracket racing.

The stall is 3000. Im not sure about the gearing. The guy that had it before me put posi in but I havent had the chance to put it on stands and check the gear. If it helps in third with the 700r4 60 mph is about 2600 rpm with the torque converter unlocked.

I would like the car to be as fast as possible so I dont care about gas milage with a different carb or anything like that, but if a 750 is only going to let me pick up a couple tenths then Ill stick with the 600 until I save the money instead of just charging it lol.

 

Tune your 600 and run it. Next week borrow a buddys 750 holley and tune it and see that will give you the best results

 

With a 3000 stall I would go with a 650-750 DP.

 

See now I was told not to get a dp unless the car is really light or a manual. I'm just going to mess with the jetting and see what it does with the 600 on Saturday, and then probably within the next few weeks ill get a 750. Anyone have a guess as to how much faster if at all the 750 would be?

Also is there anything else I should grab from the store as far as carb tuning besides jets?

 

Really light,stick or high stall I would say go DP. 650-750 will be fine and depending on the carb & will also dictate on how fast you go. You never said what heads you have either.

 

Oh yeah sorry I have Vortec heads. Oh and does anybody know what the stock primary jet size is for a holley 600 with vac secondaries? Im going to buy jets tomorrow but i have no idea what the stock size is.