I borrow a 650 doublepumper from a friend to see if it'll cure my off idle STALL. My 750 edelbrock would stall every time I took off from an idle unless I pumped it a little bit before. The holley is eating A LOT of gas in comparison, but that cured the problem and it idles pretty good even at 500 rpm! The edelbrock didnt even want to idle that low. Do you guys think a Demon would be better then a Holley or should I stick with a Holley ? Also.. will a 750 be too small or shoudl I go bigger ? Thanx

 

I'm sure you read my other post-Buddies 70 chevelle, stock rebuilt 396 was running Holley 750 DP. He jumped up to the 800 Demon and picked up .4 in the 1/4 with no fine tuning. Holley are great and Demons share some of the same parts but are a step above. If your looking for all out go and with a 408 I'm assuming that's the case stick with the DP in any carb you choose.

 

I suppose I'l just spare the long winded answer and just say DUH!

Demons are a very well made carb, but they have yet to impress me enough to justify the extra cost. Until they do, I still say stick with Holley. I'd get an 800 or 850 double pumper.

 

I guess carbs tune themselves these days

 

Well I went and exchanged my Edelbrock 750 for a Holley 750 VS. At least it's still "shiny". Hehe

All I had to do was install another power valve to get it to idle properly since I have such low vaccum. I think I went with a "15". Put #69 jets up front and the car runs A LOT better now. I feel it's a little slower on top end though. Maybe it's the VS ? I have a 700R4 now so I though maybe I didnt need a mechanical seconday carb like a DP. Should I get a DP ? Is it really that much better ?

Also... since I'm new to Holleys... what little things can I do to it to make it better in any way ? A power valve protection kit maybe... ? Thanx

 

I have that Holley 600 VS and the next "trick" is to put the adjustable secondaries kit in. You can change the secondary springs but it's a pain in the a$%. They make one that uses a screw so you can turn it up or down to bring the four's in quicker or later. Also what kind of fuel pressure do you run? If it's below 8psi your short changing yourself. Keep that carb with plenty of fuel "avaliable" and that will help a bunch, Especially at top end. Holley will take up to 9psi but recommended is usually 8psi. Just these 2 things will help a bunch, then you can get into the accelerator pump and play with cams & springs but now your getting over my head. I've never "tuned" a Holley to the max. Always had more fun rodding around.
On a lighter note-I'm assuming the guy could'nt drive but last night I seen a early 90's vette go by so I thought if I could get up there maybe he'll play too. Ended up behind him at a stoplight-he was first in line on I was on his bumper. Light turns green, he gets it, so I follow, right on his *** till my car petered out in drive @ 5000 rpm (valve float) Vette boy gave me a wave and continued on his way while I cussed because of wore out valve train. Oh well it was still fun.

 

I run 6 psi right now. Maybe I'll bring it up to 7 or 8. Keep those vettes behind you where they belong. LOL

 

Well if I had your set up I would. You know how it goes though-right now trying to get chasis ready for good motor and the one I have now is "junk". Then when I do get the real motor in it opportunites like that never seem to come around any more or your in your wifes mini-van saying if I only had my car right now. The car needs paint in a bad way but at the same time it's the ultimate sleeper. Flaking clearcoat red paint and a bright blue bumper(original had large crack), so right now I look like the dumb ******* guy/teenager (you choose) from down the road with loud mufflers-we've all seen em.