I need to replace my existing Carburetor any recommendations?  I'm considering purchasing a Holley 650 dual in-line with a mechanical choke.  I have a BB bored 30 over with an HEI distributor.  I want it to be healthy but I'm not trying to set any speed records.  Any suggestions would be appreciated.

I would go with a 750cfm mech choke for a BB as the 650 is to small. The edelbrock is a great street carb, easy to adjust & tune to your engine. The Speed Demon Double Pumper is great too, deliveres more fuel at top end & looks better, but alittle harder to adjust. But for street driving & good gas mileage I don't think you can beat the edelbrock. I've used Holly too single & double pumpers, I like the speed demon better. 

Alan

[QUOTE=knotacare]

I would go with a 750cfm mech choke for a BB as the 650 is to small. The edelbrock is a great street carb, easy to adjust & tune to your engine. The Speed Demon Double Pumper is great too, deliveres more fuel at top end & looks better, but alittle harder to adjust. But for street driving & good gas mileage I don't think you can beat the edelbrock. I've used Holly too single & double pumpers, I like the speed demon better. 

Alan

[/QUOTE]

I will agree and disagree...  i disagree that 650 is too small..  many people put too big of a carb on their engine...  there is a formula for this

peak CFM = CI * max RPM * peak volumetric efficiency / 3456

for example

675 = 432 (427 + .030) * 6000 * .90 (optimistic) / 3456

my recommendation...  do the math..  if it comes out 725 or above... get the 750..

I do agree with the speed demon recommendation..

but probably sd 650, electric choke, vac secondaries.

I, too, would reccommend a higher CFM carb. 650cfm is gonna be way too small. The 750cfm, or even an 850cfm would be a better choice.
Holley vs. Edelbrock?
The Holley is good for hot-rodding, the Edelbrock is more street friendly. Either can be adjusted to work for either application. Any of them are gonna be $$$$

I agree with most of the above...Edelbrock is more street friendly...for pure performance go with Demon or Holley, but I think the edge goes to Demon. For a street car, go with a 750, 800 or 850 cfm with vacuum secondaries and electric choke. I think for a street car not highly built up a 750 or 800 would be most responsive. If you have a big cam, you won't have much vacuum so then mechanical linkage secondaries might be best.

If you really want to do it right...install Edelbrock electronic fuel injection. You'd be REAL happy but much lighter in the wallet.

This is an interesting topic,

as I have been going through carb issues with my just built 383 stroker. I have chosen to use Edelbrock , but to no avail have I been unable to tune it properly. I started with a performer series 750 Manual  Choke. Did all the adjustments.However, every time I turn, right or left or stop hard  the car wants to stall.I changed to a 650 electrtic choke Same problem, I put on a speed demon 750cfm and I did not have the problem.With the Demon I didn`t want to change vacuum and linkage configurations, I just wanted to determine if the problem was carb related. I now Have an Edlebrock Thunder series 800cfm carb and still have the stalling problems. Edlebrock support has been little to no help .they say adjust the floats,which I have done.I even have had Conversations with Connie Kalitta`s guys and still have the problem.Anyone heard of such an issue?

Did you order there jet kit? I had to make my jets richer as they were to lean from the factory & had issues until I went up 4 levels.

Alan

I've had several Edelbrocks over time and never had a problem. If you have a built 383 and had trouble, it may not have been properly jetted to match your cam profile. That's a pretty basic thing so I'm surprised the Edelbrock techs didn't suggest checking into that.

Possibly the carb had too much CFM for the engine...that will create a stumbling problem. There's CFM and there's CFM...not all carbs are the same in that respect. The Q-Jets that GM installed on small block Vettes are rated in the 795-800 cfm area, normally too much CFM for best low end with a square bore carb, but the spread-bore configuration with air on demand keeps the stumbling problem from occuring.

Regardless of reason, you cured the problem, but it would be nice to know for sure the cause.

hey guys im still failing to see the math here..

youll see from my calculation above that unless he plans to turn over 6000 rpms that he will be fine with a 650...

assuming 6000 rpm and 100% volumetric efficiency it comes out to 750 CFM.

What basis are you using for recommending such large carbs for this engine.  Until he says this engine is setup for racing and can safely turn 8K without pistons flying out of that big block I maintain a recommendation of a 650.

When i was working at the local speed shop here on Saturdays it was our running joke that we could make so much more money selling 650's in 850 boxes because we always had to castrate a bigger carb to run on peoples engines because they over did it.  Mostly because they had the bigger is better mentality and had p*nis envy because their neighbor had a castrated 850 on theirs.

i know that some of the Q-jets were 795 CFM lets do the math..

350 * 7000 * .85 = 602.57  

350 * 8500 * .85 = 731.70 

.85 is being VERY generous to a stock 350..

I was bs'ing with someone at barry grant one day and he told me the secret to this conundrum is that in the old days a carb rating was like the old way of calculating horsepower.  795 didnt mean 795, 795 meant 625.

nowadays 750 means 750.

 

But he's not running a 350 he got either a 427 or 454 which I calc out to 725 to 750 for a street engine.

Alan