Demon VS Holley

[Walts_restoration]

Well, the original reason i was going to suggest against bg's was because numerous reports of people opening up a new carb to find shavings throughout the casting, as if it was never properly cleaned before assembly. Plus, the guys above informing me they are out of business now. The four corner idle ive heard from alot of guys was a neat feature, and my cousin runs a750 one on his 383 malibu and likes it. Same animal different name, like comparing GMC to Chevrolet.










(quiet down you four eyes, haha!)

[codydubb]

234 244 duration on the cam, the pistions are flat top single eyebrow style i dont remember the CC of them i got the bottom end already assembled for a good deal since the block we build spun number 2 rod bearing the first build and rod bearing 4 on the second build (couldnt ever figure out why) weird since it was a running engine when we tore it down personally i think it was something with the machining but the machine shop denied it and said everything met specs both times

[slugish]

check out aed performance .com out of Richmond Va. Every gearhead in the world said my my 650 holley was more than enough for my warmed up 400 .
Put one of their( rebuilt Holleys on750 cfm > truck has never run better . I recommend you read their article . This is their main business with lots of experience with matching carbs to what you got as far as heads , cam specs , compression etc. Summitt Has just started selling some of their carbs --Ithink > maybe Jegs ?

[codydubb]

Maybe i got fed a little bit of BS about the horsepower??? I havent had it on the dyno yet waiting for the weather to warm up a bit

[cableguy0]

I build hot rods for a living. We dyno every engine. Prior to now I ran a speed shop and we had a full service machine shop. We built engines everything from bone stock to 900hp naturally aspirated small blocks. I would bet money that on a legit dyno your engine is making no more than 375hp. Vortecs just dont flow on the top end and your cam is too big for vortecs in the first place. Most people who try to port vortec heads do more harm than good. Dont take me wrong Im not jumping on you on dogging your engine etc. Im just throwing out some real world experience and legit advice. A 350hp small block runs like a scalded dog. Just dont expect vortec heads to pull like a freight train past 5500rpm. They run out of flow capabilities. Yes I will say on paper that a 750 is too big but in the real world its likely the best choice. I however wouldnt have paid the extra dough for a demon. All you gotta do is go to the local drag strip. You wont find many edelbrocks or demons on serious cars. IM not saying holleys are perfect. Nothing is perfect. Any carb will require some tweaking. Most of the time the problem lies with the guy trying to do the tweaking regardless of the brand of the carb. I know some pretty serious engine builders that refuse to even touch a demon. Im talking guys that participate in the engine builders challenges etc etc.

[jrcaprai]

Sounds like you have a nice combo there really... and I don't want to sound like I'm bashing cuz I'm not, just being realistic... Flat tops in a 350 will give you a 10.3 Compression ratio, with a 64cc head. the Vortecs flow about 220 CFM which is worth about 450 HP Max...
Take a look at this article, it is almost identical to your Combo, they also test a Holley versus a Demon...
By the way, the Shavings was a problem a long time ago, and they did clean up their act. the Demon I had was Awesome, hardly had to do any tweaking to get it running really clean... I just sold a Holley 750 DP that I couldn't get to run cleanly with My Current Combo and I ended up Buying a Pro-systems 850 CFM...

[codydubb]

sounds like i need to invest in some decent heads....
i had intended on getting a set a little while after my build, but got stuck with the Vortecs only cuz i ran outta money after building two other engines (not a happy wife) lol
i hope this demon isnt as bad as i hear but aside from finding metal shavings i havent heard why they are so bad? this carb has been ran and tuned before
(not to my application) but he said it was a good carb and just needed to sell it for a blow through carb

[codydubb]

thank you jrcaprai......where is this article your speaking of

[1BadSS]

Originally Posted by codydubb

sounds like i need to invest in some decent heads....
i had intended on getting a set a little while after my build, but got stuck with the Vortecs only cuz i ran outta money after building two other engines (not a happy wife) lol
i hope this demon isnt as bad as i hear but aside from finding metal shavings i havent heard why they are so bad? this carb has been ran and tuned before
(not to my application) but he said it was a good carb and just needed to sell it for a blow through carb

Some decent heads will put you where you want to be. I'm not trying to bash you, just trying to lower your expectations so you aren't let down on the Dyno.

[jrcaprai]

Check out these heads. they are cheaper than AFR's and flow just as much with an as Cast port... your engine would really wake up with the 195cc Profilers, and Chad Speier is Awesome to work with. I have the 210cc version on my 408
http://www.speierracingheads.com/profilerecono.htm


Sorry I forgot to post the Article Duh! I'm from Boise by the way, it's good to see a fellow Idahoan online

http://www.chevyhiperformance.com/te...est/index.html

[shortbed70]

Can you say can of worms....
Quickfuels: look cool but they are hit or miss tuning wise like the old hollys
Demons: Improved holley but very picky on float level but very reliable when set and not as touchy on weather changes.

750 Is too large for a mild 350
I run a 650 speed demon on my 361 sbc
Too each its own though. Ive run several different sizes and combos on my motor and by far the demon has had the best results. I bought this thing off a shop floor covered in dirt blew it off cleaned it up and bolted it on and ran better than anything Id had on there prior.

[codydubb]

so i need to be looking for some 64cc 2.08 heads from what im gathering?

[jrcaprai]

You'd do better with a 2.05 Valve, and yeah stick with the 64cc chamber, which will keep it at 10.3 Compression, just right for pump gas

[cableguy0]

The afr 195's or Brodix ik series of heads are an excellent choice. Yes they are pricey but you get what you pay for. Nobody is bashing. Just throwing out some experience. Dont take it personal. The dyno breaks hearts everyday.

[codydubb]

lol i can take a little bashing thanks for the advice fellas, ill be letting everyone know how my demon turns out im gonna at least give her a shot.

[jrcaprai]

I still think you'll be happy with the Demon. I certainly was with mine.