Hi gang, I'm looking to replace the worn out holley on my 64 vette and could use some real life experiance.

I'm looking at the Holley HP series, Demons, and I found an old BG SIlver Claw that is still new in the box.

the motor is a 327, 11 to 1, with a decent solid roller cam (250 @ 50 and 550 lift) heads are factory cast iron but i'm trying to keep a stock profile.

any thoughts on which is the best or better carb?

A

Holley 750HP, but I am biased towards Holley. There are a handful of guys running BG carbs out there,but I've heard several have problems tuning them.

Demon, they have a carb for every application. They are a very precise carb and do require tuning but when set up properly you'll think you had fuel injection under the hood.

I run a BG silverclaw and from a performance stand point its a wash compared to a HP950. From a tuning stand point the BG has better idle and part throttle driveability. If I were making the choice then price would be one of the deciding factors. Also, if the Silverclaw does'nt have heli-coiled bowl screws you can plan on adding them or you WILL strip the threads. Been there, done that.

I've used both Holleys and Demons, and my vote is on the Demon (I've used several). Just make you get the correct one.

And the "difficulty tuning" deal is kinda garbage. If you follow the instructions, it will be fine. I've never had a problem. The only thing I can think of is that they are very sensitive to airflow changes, so you need to be a bit more careful when adjusting the idle. But hey, I'd rather spend another 10 minutes tuning to get the benefits.

OK,

do you think a 750 Silver Claw race would be too much for a 327?

BG suggested a 650 mighty or race demon but i've got a great line on a 750 Silver Claw Race. It would cost about 1/2 what a new demon would cost.

but I'd be running this on a dual plane aluminum intake. 248-252 @ 050 solid roller cam with about .550 lift. 11.5:1

any thoughts there?

Thanks

Aaron

I'm running a mighty demon 750 - awsome carb compared to my previous hp750 - better built, better features, better all the way around. Can't comment on the hp950 - never had one. I liked the price point on the demon but that was not the deciding factor. I would highly recommend demon as best bang for the buck. And if you look at some of Holley's new product specs, the are conspicuously tracking BG's thought process......

I'm running the demon on a 434sbc making 11:1 and 530/530 - 263/263 or there abouts - have to look up the spec card to know for sure - it was a custom grind from CC selected by G&G (my engine builder). It was running much richer than the 750 at first but that turned out to be more about timing. Adding the MSD 6AL made the perfect combination. Got plenty of go juice and air getting into the combustion and all of it is making the energy transfer.

Best,

Just make you get the correct one.

thats what I'm talking about, tuning aint garbage if you get the right BG carburetor...so which one is the correct one? cheaper by the dozen :D

Yeah, it can be difficult. I've had good luck using BG's tech support, they usually seem to steer me in the right direction (I've heard opposing views, though). With the engine I have now, they recommended a Mighty Demon. I personally thought that was too much, I thought a Speed Demon would be the ticket (with the choke and all). But man, they were right. What a good performing carb. Even if it's 40* outside, that motor fires up on the first flick of the key with no choke. My wideband sensor says my A/F ratio is darn close at all RPMs, and the transitions are very good. And it's as easy to tune as any other.

On this combination the 650 Mighty Demon is going to be a better choice for overall performance. The slightly smaller carburetor will give better idle quality, throttle response, acceleration, and overall performance.

my only problem with the Demon's are airclearer clearance.

this will be going on a stock "appearing" motor and the factory aircleaner must be used.

the only way I could use a Demon would be if I put holley bowls on it, and I'd rather not do that.

if I use the 750 Silver Claw Race, will it still be drivable? or simply too much carb?

This car will only see street duty and most of which is typical city driving. it is a 4 speed to cracking the throttle once and a while to clean it up shouldn't be a problem,

i just don't want to be fouling plugs every week.

with the 650 silver claw I had on a 302, it was perfect so I was hoping the 750 on a 327 with a larger cam would work ok.

any thoughts?

Aaron, the 750 Silverclaw that I now run on my 422 is the same one that I ran on my previous 10:1 355 with a 244@50 hyd cam. Yes it will work for what your doing and no I don't believe you'll be fouling plugs. The 650 would be a better choice especially if your doing alot of street driving, but the 750 will work. I guess it just depends on just how "good" that price is for the 750. If you do buy it you WILL need to use thread inserts for the bowl screws so plan on adding another 40 bucks to the price of the carb.

I'll be paying 325 bucks for the BG silverclaw Race.

it will require 2 inexpensive fittings to hook up to my fuel lines.

otherwise, i'd have to buy the demon for 500 and get holley bowls for it.

thats why i figure i'll have about 200 bucks less into the Silver Claw (even though it was run)its in excellent condition.

unless someone here can sell me a set of center hung float bowls.... that I can put on the demon.
if I buy them new from Holley, then I need to deal with getting floats, hardware, pump housings, etc. and that will cost a fortune.

thats why I like the Silver Claw idea better becasue it will be a simply issue.

Aaron, is this the same engine you were considering the 30/30 or LT1 cams for? Just curious. If you don't have a cam yet, you may want to contact Isky. They have a new line of high-lift, short duration solid flat tappet cams that are pretty aggressive. I don't have the specs with me at work, but if I remember correctly,the cam they recommended for my 377 (4.00" bore, 375" stroke) had .530" I/E. 278* adv, 240* @ .050", on a 110LC. I was gonna order this cam with the "4/7" swap, and I'm considering getting it on a 112LC. This cam would lope nicely in a 327, and might even run a little better on the street than such a large roller.

Wes,

yes this is the same motor,
i'm not going to use either the 30-30 or LT1. No matter what those guys say, I know that there are much better, more effecient cams, out there than the LT1.

I'd like to keep it close to where the 30-30 was duration wise and crower recommended a 250-252 @050 with 570 lift on a 112. That has like 40 degrees less seat duration so the cam would be much more responsive, and be a hellova lot more effecient even with that much more lift.

i'm thinking I might even go smaller to about a 242-248 @ 50. but i got to have the idle.

Aaron

Originally posted by aaronz28:
Wes,

yes this is the same motor,
i'm not going to use either the 30-30 or LT1. No matter what those guys say, I know that there are much better, more effecient cams, out there than the LT1 which is what i currently have and am not happy with it.

I'd like to keep it close to where the 30-30 was duration wise and crower recommended a 250-252 @050 with 570 lift on a 112. That has like 40 degrees less seat duration so the cam would be much more responsive, and be a hellova lot more effecient even with that much more lift.

i'm thinking I might even go smaller to about a 242-248 @ 50. but i got to have the idle.

Aaron

The 750 is not going to idle as clean, or respond as well driving around as a smaller carburetor would.

Aaron, I agree with you about better cams being available. Both cams would have a mean sounding idle, but I bet you'd like the driveability of the smaller cam better. Are you gonna have the car/engine dynoed after you get it back together? Wes

Wes,

my plan is to put it on an chassis dyno after its all back together. I'm still driving it now with the LT-1 cam and it runs fine, but I'm sure a new cam would just kill the LT-1.

I'm gonna gather all the parts and then once I have everything, i'll do it over a weekend so I can get back in and drive it.

I've always tuned my cars by drivability but I'd like to know just what she'll put out after the cam swap.

thanks

Aaron

Aaron, I'd love to see the dyno results when you get them. I bet you exceed both peak and average torque and horsepower vs. the LT1 cam. Wes