Best Carb

[‘69_Sunfire_RR]

Figured I’d revive an old topic...
Folks, I have a pretty stock 383 in my ‘69 but I’m looking to get a little more out of it for fun cruising, etc. I’m not looking to race the car, at all, but I want more out of this setup. 900 miles on this build. This is a low mileage engine which didn’t require boring. Forged flat tops, stock crank, rods, and heads. Stock 2.08/1.74 valves. New Mopar cam (.450/.464) which I’m told is the closest to the stock RR or Magnum cam. Matching Mopar springs, stock 1.5 rockers. 4-speed, newly rebuild 489 case with 3.55’s. Stock 2.5’’ exhaust, factory replacement exhaust system. Intake is a Edelbrock dual plane performer 383. I still have the original ‘69 cast iron intake in excellent shape. Currently running a Holley 670 Street Avenger BangHead: ). I’d like to go to a different carb. Does it make sense with my setup to go to a true double-pumper (dual metering blocks, dual accelerator pumps, mechanical secondaries, etc.)? I intend to go to a higher lift cam, full length headers, different mufflers at the very least, and a RPM intake. I’m looking to get around 450 hp at the crank. Thank you all!

 

[ykf7b0]

Would you know the compression ratio?

 

[‘69_Sunfire_RR]

It’s 10.0:1. Thank you.

 

[ykf7b0]

Good! With that compression and a little more lift and more duration @ .050 with a new cam, opening that exhaust up to 3 inches, and putting on that Performer RPM I will recommend a Holley 750 double pump with mechanical secondaries. It will ROCK!!!

 

[criner28]

I also have a stock 69 383 with a Holley 670 Street Avenger. This carb isn’t working for me. Hard to start, hesitation even

 

[criner28]

Sorry, didn’t finish. Hesitates even after it gets warm, heavy fumes inside car. I just want a carb that works. I’ve taken the car to a “Holley expect” no help. My Mopar buddies say to get a Edelbrock. Any suggestions on type and cfms?

 

[RKNRLR]

I was running an edelbrock 750-ish cfm when I bought the car. Cast iron heads, mild cam, really ran great on the street. Took the car off the clock with the 3:55 rear end.

 

[Russ69Runner]

I am running a 650 cfm Holley. Have not driven the car but the motor ran well with it. Idle well and pulled it into the garage with that on it. You might try to change the jet's in the carb. Sound's like you are over fueling the motor. Have you checked the air mixture screw's.

 

[69hemibeep]

Its to bad you guys cant get the 670 tuned its not a bad choice for a mild 383 it is larger than stock. 2.5" pipe with free flowing mufflers are more than enough for your build, 3" will make it loud and more for 550 plus HP. Just my opinion

 

[Russ69Runner]

I agree you have to work on the exhaust to get rid of what you are putting in the motor. Need a good balance of intake as well as the exhaust.

 

[criner28]

When I bought the car about 6 years ago the Holley ran pretty good, however the last 3 years or so it has not run so well. Maybe I should give it another chance, but I really don’t know what to do. Since it ran ok before, I don’t think the jetting is a problem. The air mixture screws are adjusted properly. It idles good once it warms up and it accelerates good, no missing. What is causing the gas fumes inside car? I appreciate any help. I feel that a good carb man could fix it, but don’t know any.

 

[1968 man]

Check the firewall for any penetrations if none then check the vent tube on the gas tank, if no luck there check the seal on sending unit. the fumes could be coming from the rear of the car. Need to find out where they are coming from for sure. (Kaboom Not Good)

 

[Russ69Runner]

The Holley I have had nitrate float's and not brass float's. It would not adjust. So replaced the floats problem solved. Their is a screen in the inlet fuel port they do get clogged up also. Just a few thing's. Do you see any gas around the motor. Those power valves tend to leak when they get old.

 

[dmartin]

My 750 dual line Holley does great, you may have an exhaust leak somewhere cause that’s what happened to me and I thought it was the carb but it turned out it was exhaust leak

 

[Russ69Runner]

Good job Dmartin another thing to check out.

 

[69hemibeep]

Check your trunk seal, is it raw or burned gas?

 

[criner28]

Thanks guys, you have given me some things to check out.

 

[criner28]

Could a bad pcv valve causing my fume problem? I want to replace it, but having difficulty removing it from valve cover. What is the procedure? Thanks

 

[Ranger]

It just pulls straight out. The procedure - pull harder.

 

[criner28]

Thanks, I pulled harder.