How's everybody doing? If money wasn't an issue and you had a pretty strong 355 and trany, which would be the better choice,,,,, Edelbrock 600 or Holly 670?

It will depend on what you expect from the engine.

If you plan to race it, the Holley Street Avenger (670) is easier to change jets and tweak at the track. Making it infinitely more adjustable.

If all you want is a high power street machine, the Edelbrock Performer (600) is more Plug-and-Play. Set it and forget it. You can change jets and springs, but the carb has to be virtually disassembled. Not ideal for quick changes.

Of course this is a discussion that's been done to death, but I'll add my .02. I had a 600 Eddy on my 355 and just recently replaced it with a Holley Street Avenger 670, and man, what a difference. Night and day. Love that Holley. But it did take quite a bit of tweaking to get it dialed in to my motor.

I'm sorry if it's been done to death. I don't have a whole lot of time to check the forums.
I also don't know much about tweaking carbs. I guess I know enuff to be dangerous. I can probably pick stuff up pretty quick tho. Maybe I'll get the Holly and see how it goes.
thanx,,,,,,,,dug

Hey Doug, Don't take offence to me saying it's been done to death. The old Holley vs Edelbrock argument is like Chevy vs Ford or Apple vs Blueberry pie. Wasn't implying anything more than that.

No offense taken bud. So if I DID get the Holly, would I be buying a couple jets and parts to be changing out to get it working right, or is it more like the plug-n-play edelbrock?

I've had them both on my 454, (larger cfm though) and I now have a Berry Grant Demon on it, and love it. The response is outrageiously better than the Holley or Eddi. It is also a plug & play, but a tad bit more $$. See the 650 below, just another opption to consider.
http://www.jegs.com/i/Barry+Grant/132/1282010VE/10002/-1/743583%7C10271
http://i300.photobucket.com/albums/nn18/coyoteon2/AMW-bc-front-Larry.jpg
http://i300.photobucket.com/albums/nn18/coyoteon2/102-0287_IMG_1.jpg
PS. And should you want to play with differant jet sizes, it uses the Holly Jets, In fact it is almost the same Carb but more advanced.

:cool: between the edelbrock and the holley, i prefer the edelbrock for all around use. having had both i can say that both have their strong and weak points. the edelbrock is more street friendly, and usually has better street manners than the holley does, but it is hard to beat the holley throttle response. the holley is easier to tune, but you can get the edelbrocks fuel curve closer to what the engine wants. one thing i dont like about the holley is that it runs fuel through a gasketed area which is an invitation for leaks. i also dont like the power valve system either. in my opinion the edelbrock has a better system, though it also has issues also. the edelbrock on my elco is just about perfect out of the box, though i may get into it and see if i can lean it out a bit for some better fuel economy.

Well, if you have the money. I would suggest one of Holley's HP street series. Either the 650 or 750 mechanical secondaries. i know a lot of people will say I'm nuts. But these things rock.

tom i agree. i LOVE my Holley 950hp....

I would say holley because I have an eddy and it is a pain in the ass to tune

I would say holley because I have an eddy and it is a pain in the ass to tune

OMG I've been so excited the last couple days I forgot to post. I bought this Holly 600 off of by buddy for $80, brand new still in the box. The same guy that sold me the bad ass engine, and it WOKE the monster within!!!
WOW was I surprised!! After the first ride up and down the street my hands were actually shaking!!! HE he HE
YEEE HAAAA

Glad you're happy and glad you got such increased performance for just $80. You done good by almost any masurement.

Now, Let me add a twist regarding air fuel ratio. Ideal air/fuel ratio (chemically speaking) is 14.7:1 That is, 1 pound of gasoline mixed with 14.7 pounds of air. For maximum performance, the ratio is more like 12.5:1, give or take a little.

You may see where I'm going....

The jump in performance you just experienced by going with the Holley 600, may be due more to a change in air/fuel ratio than of carb design. Or, it could be because the Edelbrock you removed may have had something wrong with it.

Either way, for $80, I'm glad you're happy with the result. Just be a little watchful that your new carb isn't burning excessive fuel.

With a little tweaking, they can be tuned to get 14.7:1 on the highway when you want economy, and 12.5 when you stick your foot in it adn want performance.

As for me? I run Holleys on both my 454 playtoys. Great performance, but then I only get 10-12 MPG, (like you now)!!

Happy fueling!!!

Fuel mileage??? That went out the window when I built this monster! :lol:
Yea I think it is both the increase in air/fuel and something wrong with the edelbrock. When I would put my hand over the carb on the edel, it would slowly die, but when I put my hand over the holly it sucked it down onto the carb so hard it scared me. LOL
How do you go about adjusting air/fuel? And how do you know what ratio you got?

...but when I put my hand over the holly it sucked it down onto the carb so hard it scared me.

Should have warned you. Sorry.

Holleys come out of the box VERY HUNGRY! :rockon:

How do you go about adjusting air/fuel?

In a word, swap the jets. Larger sizes for more fuel (richer), smaller sizes for less fuel (Leaner). Lots of instructions around on how to do thi. Or, you can take it to a Pro. It's a 10-15 min job. Tops.

And how do you know what ratio you got?

4 ways that I know of. Maybe more.
1- Look at your spark plugs, if they're brilliant white, you're too lean. If they're sooty black, you're too rich. Between those two extremes it gets hard to tell. Ideal color is somewhere between a taupe and tan.

2- Approximate it based on the jet sizes and vacuum levels you have now. Holley boxed instructions should say what's in the new carb, based on the serial/model number. Their website or help line might answer the questions also.

3- Wide band air/fuel sensor/meter. Either the kind that sniffs the tailpipe or screws into a bung in the exhaust (best but also $250 or more)

4- Take it to a reliable performance shop for a chassis dyno "cruise". Likely less than $100. For just a little more, they'll set the average A/F ratio wherever you want it and probably give you a chart of the results.

Good luck.

Alright cool. I'll check all this out. I'm looking around for tech stuff on my new carb now. The numbers on the air horn are 80457-2 2398 if you happen to have any idea what it is exactly that be appreciated.
I've been meaning to have it dino'd for a while anyway. There's a place about 30 miles away that can do it.
This engine is so mean, I was told that it came from the factory at 300hp. And all the stuff I've had done, it should be 350-380 I'd have to guess. It has 400 sb heads on it now, and I'm looking for a set of 350 heads that will put the hp even higher. When I had it machined, the mechanic told me that the block alone was worth $1,200. I was SO happy. The guy(my best friend) that sold it to me wasn't too happy tho! :cool: But he is glad that it went to a friend that would take care of it. He owns a '70 Cyclone thast is REALLY mean and runs in the 7,000 rpm range! WOW
Thnx 454

No problem. Good luck with your tuning.

Just so you aren't too too disappointed, remember that on a chassis dyno you're measuring rear wheel horsepower, not engine dyno horsepower.

The drivetrain and engine bolt-ons usually suck 20-30% off the Engine HP ratings. If you're getting a true 300 RWHP, then you're likely putting out 360 or more HP at the crankshaft. Conversely, 350 crank HP could show up anywhere between 250 and about 280 HP at the ground.

Yea thanx. I'm no speed demon, but the last couple times I ripped up and down my street, it had my hands shaking!!
It sounds like you know a little about carbs. The last time I tromped it, it stalled when I got back to my parking spot, it was dumping fuel out the float bowl vent on top of the carb. What does this mean?

Probably got some trash in the float bowl's needle and seat. Easy fix on most Holley's. Lots of info around on how to fix/clean.

You running a fresh fuel filter?

ive got an edelbrock 700 or so in my 454 and it works like a charm, i dont think ive ever had to adjust it since installing it 7 or so months ago. but since my engine rebuild, the reccomended CFM is around 900, so i think im gonna end up going with a holley 870, just cause edelbrock doesnt even go that high, and i could care less about fuel economy, just need speed :D