I'm running a 650 Speed Demon w/ Mechanical Secondaries and I absolutely LOVE it. I agree that a 750 is probably too much for your setup. I'm running a GT-40X w/ a Performer RPM, a Crate Demon for the FRPP GT-40 crate engine and shorty headers. It absolutely SCREAMS all the way up to 6500 rpm very comfortably. The jets, most gaskets, springs, balls, etc. are completely interchangeable from Holley to BG and vice versa. I love the support I've received with my carb. In fact, they offer a "Crate Engine" 650 Speed Demon (which I opted for) that is flowed, metered and jetted specifically for my application. Check out richdesbiens on ebay. He stocks all Demon carbs and outsells everyone else I've checked. I say go for it! You'll be happy you did!
Which carb? Im confused.
- Thread starter NosPony
- Start date
thumper460
Founding Member
Both are about the same cost... the Demon is the BETTER Carb. Our experiance is they are a little on the lean side and will need a jet change for a modified engine.. but they are all the best mods, all ready incorporated in the holly... the Demon is the better Carb!
Just me........................
Thumper
Just me........................
Thumper
1984Convert
Member
I tried a Holey 670, a demon 750 and then ended up with a Demon 650 on my 347. The 750 wasn't as crisp as the 650 was on my engine. The Demon is superior to the Holley in craftsmanship and performance. It uses Holey parts (gaskets,jets,everything), but has cleaner castings and billet baseplate and jet plates. The Demon has idle adjustments that are easy to adjust on all 4 barrels - the holley just had them on the front 2. Now I just upgraded to the Holley supercharger so I had to increase to a Demon 750 blower carb. I have my Speed Demon 650 for sale if you are interested - still in it's original box.
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