Building a 383 stroker and deciding on what carb to get.
Called Jegs and Summit and they both recommend a Holley Street Avenger for ease of use. But I have read and heard alot of great things about Demon and the Speed Demon looks really good.
The Demon is about $50 more.
What do you all think? How easy is a Holley to set up compared to a Demon? Is there that much difference? Wouldnt I have to adjust and tweak either one?
Thanks

 

You will get many opinions of carbs, depending on personal favorites, but any one you get will have to be tweaked and tuned to your engine. Having used 3 brands myself on my 383, here's my .02 from my experience, in order of rank:

Ease of use - 1. Edelbrock (750 or 800 cfm)
2. Demon
3. Holley

Performance- 1. Demon
2. Holley
3. Edelbrock

 

i have a ZZ4 in my '79, initially i put a holley 750 and my oil got dirty the first tank of gas, learned the equation to determine the proper carb and my motor needed 595 cfm, i bought a demon 650, the 650 came with written and video instruction/explanation of how to tune and adjust the carb, the holley came with nothing but vague paper instructions. I love the demon but my holley was alot stronger off the line. I had to specially make a riser for my demon breather that would clear the electric choke assembly. They do make breather units to compliment the demon but i redid my unit since it was new, the breather fit well on my holley. The only other complaint i will say about the demon and i've heard in the forum is the butterflies due to motor vacuum don't always shut completely and the motor may rev just a tad high, i had this happen a few times and tap the pedal and it sort itself out.I read about the issue in the forum and realized it was an actual problem.I drilled a hole on the outer of the throttle linkage to mount my throttle cable to make my gas pedal easier to press while i stiffened the springs that assist closing throttle..I am partial to Demon even with those issues

 

Any proper cfm carb can be set up for top performance. Take your pick. A quadrajet can be set up for top performance too, and still give you good drivability and economy on the street. And at 750 cfm, it will be plenty of carb for your stroker. God bless, Sensei

 

I think I will lean towards Demon. I have installed a few carbs but never tweaked one to the extent that I will be on this one, and the video sure would help.

 

remember you need a heat shield and i also used a spacer

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Just a question...why does he need a heat shield?

 

Because if you don't use one, the fuel will boil in the accel pump wells after shutdown and cause really bad hot-start problems.

 

Hey Lars...

Why does it sound like this should be an automatic pratice? I am in Texas and have never had an issue restarting the car after a nice long ride with heat buildup...

 

A lot depends on the vapor pressure of the fuel in your area. The EPA regulates vapor pressure for some States during some months. Other States get some really trashy fuel that has a tendency to boil off very easily. Perhaps you're one of the lucky ones in TX and get some good fuel. Many other areas have fuel that will boil in the accel pump well immediately upon shutdown if the shield is not used. For this reason, I recommend using it on all Holley and BG applications.

 

Lars...As usual your explainations are great. Thanks, now I understand why some must have them and others may not. I did not know it had to do with good or bad fuel.

 

thanks lars, i will work on installing a shield soon

 

I'm considering a 383 crate engine from enginefactory.com.
It's their 460 horsepower unit. http://www.enginefactory.com/460stroker.htm

They specify an Edelbrock 800cfm Thunder AVS series carb.
Has anyone any feedback they can provide on this carby?

regards

tom

 

I've used the Edelbrock 800 cfm (Performer, not Thunder AVS, but performance is the same- AVS just tunes easier). My 383 stroker is around 460 HP as you're considering. I was very satisfied with it on my "street-strip" '69, and ran an 11.81 ET with it. It was definitely more responsive than the 750 cfm Edelbrock which preceded it. I now have an 825 Mighty Demon, which I got for better performance.......almost 2 tenths gain, now 11.62 ET. The Edelbrock worked well, but for more performance, I'd consider a Demon before you buy.

 

These heat shields, is this something you buy or make up?

 

I would also like to know where to get the heat shield.

 

Ok so I went with a Speed Demon..
now about this heat shield, (same question as above) can I buy one or need to make one?
What guage material is it made of? And any other specs you all may have would be great.

 

Make sure you watch the video and check all you settings before you start it. I had to go back to Jegs and physically check the carbs with my feeler gauges. The throttle linkage were all bent up from shipping and could not get the initial settings to match at all venturis.
My opinion on the carbs:
I have been through on my 350:
1 - Elderbrock 650 AVS thunder (flooded all over the intake from bad gasket in 10 months)
4 - Speed Demons 650 Mec sec(worked well once I found one not damaged)
1 - Mighty Demon - more pleased with then Speed Demon
Since a 383:
1 - Quick Fuel Q-750 - mec sec were hard for wife to drive with auto, other then that was the best carb I had to that date
1 - Quick Fuel Q-750PV - vacuum sec, is still on the car and is probably the best carb I have ever had, bad point was it took much more tuning to make this carb work well then the Demons, which really doesn't make sense since most of the parts are the same

 

Here's a picture and part number. Holley part, from Jeg's, but Summit has them too..



p/n 510-108-70

 

You buy the heat shield shown above, but then you have to modify it. You have to shorten both the front and rear (or it will hit the thermostat housing in the front and the vacuum fittings in the rear), you have to trim the sides to not hit the carb linkage and fuel lines, and you have to bend a jog into the shield so it does not compress the accelerator pumps. If you order the shield from Summit, you can have it drop-shipped to me and I will do the mods for you. E-mail for info:
V8FastCars@msn.com
My paper on how to install a BG carb shows the shield mods.
Lars