Quick question, seem to remember reading somewhere the recommended carb for a 455 was a 750cfm, just looked at what's on mine currently and its an Edelbrock 650cfm. Is it worth changing to a bigger carb on what I assume is an otherwise stock 455, or stick with the 650. Only reason I ask is that the 650 needs a rebuild (if left for more than a day or so there is no fuel in the float bowl so assume it is leaking somewhere), but no point in rebuilding it if I am better off replacing.

Cheers.

 

For one thing changing to a Holley 3310 750 would be like installing a new engine in your car!

 

x2 on a 750. I like double pumpers better then vac secondary's.

 

The original Qjet was 750 CFM. A 650 E-brock is too small unless mileage is your primary concern. The type of carb (Qjet, Holley, E-brock, Demon) is your choice. Discussions on the merits of each are like discussions of religion, only more violent.

The best match for your application will depend on the status of your engine and your intended use.

 

Now for the opposite opinion on your Ninety Eight. You can feasible get away with the 650 if it's a stock engine and just a cruiser. If your were going to modify it and run WOT everywhere then upgrade the carb.

 

That's a good one Joe....about carburetors am I leaving much hp on the table running a 750 on my 468.It's has Eddy heads and a 236/244@ 50,538 lift hydraulic roller cam,400 turbo trans,3.73 rear.Also a performer manifold with the divider milled.Car runs good on the street.Have not had it to the track...yet.

 

Yeah, your combo sounds like it could use more carb at the track. This will be a trial and error undertaking to optimize it, however, as you'll need to swap carbs and get each properly jetted to match the combo.

 

Kinda thought so.I'm never really at wot on the street,let alone for a whole 1/4ml.I've noticed my fuel pressure drops from 6.5lbs to 3 or less when I get on it for a second or so.Using a holley mechanical pump,I need to check that out also.....Thanks Joe.

 

Just curious....
What is "wot"?

Thanks...

 

Wide open throttle

Basically peddle to the floor

 

Wide Open Throttle

 

What's the number on the front of the carb? I know they make a 650, but I personally have never seen one. Most places only sell the 500, 600 and 750 CFM carbs.

And doing a rebuild on one of those is actually pretty simple.

If you are just cruising the 650 (or 600) if tuned properly should be just fine. I'd guess from your pic there that it's in a big car and you're not racing it soo....
I guess it just depends on what you want to get out of it.

 

I would leave the 650 on there. It's a stock motor,and you are not spinning it high enough,or making enough power at the upper end to justify getting a 750.
As for the Holley 3310,that's a nice 750 vac secondary carb. I put those on a variety of healthy street engines,and they all ran and performed very well. You just don't need one for a stock 455.

 

I have an apology to make, its actually a 600... Edelbrock 1405. Guess the 600 is going to be even more restrictive than a 750.

I'm not so worried about mileage, its going to be a dry day, weekend toy, not a daily car... even with regular gas at the equivalent of $8.85/gallon here.
I have no idea what state the motor is in, but when I pull it to do the pain / bodywork around the engine bay it will likely get an overhaul.

 

I had 600 Edelbrock carb on my 400 and even thou the car is mainly a show car I couldn't stand not having any power just going down the road.
I have the Quick fuel "slayer" 750 now and its the best. Its got an adjustable vacuum secondary pod.

 

I run a Holley 850DP on my 461 and its a beast now compared to the 750 I had on there. I get around 5-7 mpg the way I drive. When the secondary's open up now hold on for dear life!

 

When I ran a carb on the 507,I ran an 830 Holley chokeless. We also took a Yorker,cut & welded a dominator throat in it,and ran an 1150 dominator. The track performance was nearly identical as the 830,but the dominator was a lot more finnicky to keep streeable. I ran the 830 pretty much right from the box.I went down one jet size,and up one squirter size.I didn't have any issues with it loading up.I could let it sit and idle all day.I got 12-14 mpg to and from work.I have no complaints with that set-up.
I determined mpg by running it out if gas,then putting 5 gallons in,and running it until it quit.Just make sure you take another can of gas with you,so you can get back home.

 

My spedo is way off and have to Use a GPS and a full tank.... I run 80/80 jets 30cc/50cc pumps and 45 for both accelrators. I still have to tune those and the cams and it'll be perfect