yeah see i hear people run simliar sizes with similar engines. but i did some reading and i think that this particular one will be to racey for me.

my friend gave it to me off his mildly modified 350 chevy camaro because it was a little to racey. he gave it to me at the time because i have a 351 cleveland mach 1 that would fit up perfectly with this size i think.

 

I have a 650 edelbrock on my 289 that is stock besides the carb and the intake. Runs like a dream. I would hold onto it.

 

like i said, if it wasn't vacuum secondary i woulda taken it. :|

 

its cool salik, i after you mentioned that i did soem research and i can see why you would want a vacum.

its also one of the reasons why i think its going to be a little to much for my motor. and a little to rough.

i still want the headers.

 

The carb should only run as lean as you want, regardless of the port size, and the primaries in the Holly may not be that much bigger from the smaller carb you currently have. your MPG may not be that much different unless you do a lot of freeway.

If you want to get a 550 cfm 4 bbl for now, you will still feel the difference when you step on it. When you are ready to upgrade in the future, rebuild as many parts as possible together to save some time and dough. You say your rig is old? When you really need to get that valve job, get a new intake and carb installed then.

CP

 

i wasnt planning on putting a new carb on anytime soon. the motor runs good. no problems

but its all original. so the heads could use replacing or at least a valvejob. as well as a new intake and carb.

but im more concerned about drivetrain and brakes before engine.

and in the end i only want to make 300hp. which i think would be possible with the 500-550, gt40 heads, intake and small cam.

 

A mechanical 650 is way too much for a stock non-hi-po 289. Even a vacuum secondary 650 isn't going to beas efficient as a smaller carb. The engine will never pull that much air. You may be able to tune it to run ok, butitstill won't beideal A smaller 500CFM carb will do just fine power-wise and will increase throttle response andefficiency by increasing the vacuum signal at the carb venturis. A 1.08 venturi (~480CFM) Autolite 4100 is perfect for a stock 289, but an aftermarket carb will give you more adjustability to work around other parts in the future,like headers and a cam.

With a real 300hp (net, not gross), I'd be thinking about 550-600CFM carbs when the time comes. I have a 600CFM Edelbrock on my 331 and it's absolutely perfect for it. If/when I upgrade heads, I'll probably drop on a Demon 625.

 

^^^^
+1

 

^ aye and amen
on the other hand I must admit I sinned.
I wanted to go for a 525cfm, but I couldn't resist the cheap offer of a used 570cfm.
I hope I won't regret it.
The good news is: I never will experience 525 then, so I can claim as well it runs great