the right carb?

ironman_gq

what would work better for my off road jeep with a mildly built 304 a holley 600 with vacuum secondaries or a 500 edelbrock performer. I would need to switch to offroad needles in either one but which will work better/ easier to tune. I know the edelbrocks are significantly cheaper but there is more support for the hollerys

GratefulTread

I had nothing but trouble with a Holley on a 360 in my 82 J10. I bolted on an Edelbrock 650, adjusted the idle and drove away. The engine never ran better. Big power. I was suprised there was so little to tweak to get it to run :t: Broke the diff. Oops! #-o Probably not directly related...

AMX69PHATTY

Edelbrock's are less tempermental, touchy, and troublesome
than Holley's, but Holley's outperform if they get tuned in.
They're so tuneable it's both good and bad.
Although Edel's are probably better for off-road.
Read an on-line article where a Quadra Jet outperformed all others for off-road.

76-cj7

I've got a 570 Street Avenger on my 304 in my heep and love it.....no stalling problems up hil or down hill always idles smooth and starts up fine.

tufcj

Can't tell you in the Edelbrock, I've never run one off-road. I ran a vacuum secondary Holley 600 for years before going to EFI (first on a radically built 304, then on a mild 360). With the off-road float bowls (spring loaded floats) and needles, slosh tubes, and whistles, it ran reasonably well. I had a problem that if I lowered the floats to a point that it wouldn't flood when the front dropped suddenly, it would starve for gas when it was extremely nose down. I used it in a rock crawler. I went EFI as soon as I could afford it, and have never looked back. Bob tufcj

ironman_gq

I might go to edelbrock. the holley I have is very tempermental and seems to be alergic to the highway and town. seems everytime i take her to town or down the highway it ends up off and the next time i take it out i have to fight with it.

zero cool

If it were me, I'd go with the 470cfm Truck Avenger. I've wheeled with several people using Edelbrock performers and they just don't do well off road. I ran a Truck Avenger on my old 85 Grand Wagoneer and it was just about as smooth as fuel injection at any angle I could put it. Sure, it was a bit temperamental but for off road, I wouldn't go with any other carburetor.

Goose

Yep this is one of those questions.. Opinions ?/ oh yea everyone has them.. truth is either carb is fine.. If you get a good one. most of the complaints for either brand are due to poor tuning or expecting one brand to do something the other wont.. face it, a carb is a bowl of gasoline sitting on top of the engine, and thats the limiting factor right there. For me the fact that unless you totally screw up, the Edel will get you home. it is easy to tune and it CANT leak,, it is a one piece bowl with a lid on it. the only gasket is on the top cover. and it tunes without taking it apart.. (meterng rods , step up springs, vacuum secondary springs etc) are all changed externally. the Holley is a good carb but they have about 40 places to leak either vacuum or fuel..and until you have trouble on the side of the road it is hard to explain the difference. you can take the Edelbrock apart without replacing gaskets. the Holley not always. the one advantage of the Holley is that you cand find parts for them everywhere.(And yea I know they said they fixed the power valve blow out problem..but I still see them blown all the time. now no one checks them since "they fixed that") Edelbrock bolt it on and forget it. the Holley tinker tinker tinker.

Patf10

im running a edelbrock 500CFM on my 360, i rejetted it to around where their 600 cfm carbs are, From the info i gathered the 500 and 600s are basically the same. I was wondering what tuning combos people were running

AMX69PHATTY

just as ref, understanding is, manual choke edels come jetted richer than electric choke edel's, that can be a little on the lean side

Rhinolined360

470 truck avenger lmao I would go with the 670 truck avenger no lower than that! come on!!!!!!!!!!!!!!!!

zero cool

Rhinolined360 wrote
470 truck avenger lmao I would go with the 670 truck avenger no lower than that! come on!!!!!!!!!!!!!!!!

It's a 304...

I ran a 670 on my 360 and I'd recommend a 770 for a well built 401. But for a 304, the 670 is overkill. You'd have to down tune the 670 so much that you would hardly ever get into your secondaries. And at that point, you may as well just toss a MC2150 2bbl on it.

A 304, unless you're running at 5K RPMs or more on a regular basis, will run great with a 470.

dbesade

zero cool wrote
Rhinolined360 wrote
470 truck avenger lmao I would go with the 670 truck avenger no lower than that! come on!!!!!!!!!!!!!!!!

It's a 304...

I ran a 670 on my 360 and I'd recommend a 770 for a well built 401. But for a 304, the 670 is overkill. You'd have to down tune the 670 so much that you would hardly ever get into your secondaries. And at that point, you may as well just toss a MC2150 2bbl on it.

A 304, unless you're running at 5K RPMs or more on a regular basis, will run great with a 470.

Just a note that the 304's came with the 1.07 venturi MC2100.. the MC2150 isn't all the much bigger than the MC2100, with a performer intake, the MC2100 will cause cause a performance hit rather than just going with a decent 4 BBl

-Dave

jeepsr4ever

Do your carb math and then add 30% to your required CFM and you have the perfect CFM requirement for your engine.

Mudrat

To help dummies like me .... an on-line Calculator

Or simply, a 360 that's .030 over needs, with NO OTHER MODS, ₅₈₁ CFM with a 100% VE (volumetric efficiency) and a top end of 5500 rpm. But who's perfect? At 90% VE that same engine only needs 465 CFM, or with MCs math - it works out to 605 CFM. :-|

So the lesson for today class, polish ur heads, clean-up the intake and exhaust flow paths, go bigger on the bump-stick and let that puppy breathe!!

VE = Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More correctly, volumetric efficiency is a ratio (or percentage) of what volume of fuel and air actually enters the cylinder during induction to the actual capacity of the cylinder under static conditions. Therefore, those engines that can create higher induction manifold pressures - above ambient - will have efficiencies greater than 100% (blowers, etc...). Volumetric efficiencies can be improved in a number of ways, but most notably the size of the valve openings compared to the volume of the cylinder and streamlining the ports. Engines with higher volumetric efficiency will generally be able to run at higher RPM and produce more overall power due to less parasitic power loss moving air in and out of the engine.
-Wikipedia¬Æ

Rhinolined360

I used the holley carb selector for the 304 http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp
it came out to the 470cfm lol that sucks

Mudrat

Rhinolined360 wrote
I used the holley carb selector for the 304 http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp it came out to the 470cfm lol that sucks

Well by straght numbers that would work, but AMC engines like to breathe easy - thus MC's 30%-over rule. I kinda went small myself, I have 600 CFM sitting on a built 360 - shoulda gone 750 (758 CFM at 100% VE) probably :oops:

Oh, well. Live and learn :wink:

ironman_gq

will a 500 be large enough I dont plan on revving past 5500 and would really like to keep most of the power down around 1000-3000rpm

dbesade

ironman_gq wrote
will a 500 be large enough I dont plan on revving past 5500 and would really like to keep most of the power down around 1000-3000rpm

I have a Performer 1406 (600CFM) from from the bulltear store.. works very well on my 304 and I even got 17-20 MPG on the road pouncing around town..

-Dave

Mudrat

dbesade wrote
I have a Performer 1406 (600CFM) from from the bulltear store.. works very well on my 304 and I even got 17-20 MPG on the road pouncing around town..

-Dave

That's 'cause you have a light foot Dave . . . NOT!!! :shock: :mrgreen:

The only thing more scary than riding with Dave on-road was riding with MC off-road in the Green Machine we stole at the FJOA Scramble 111!!!

By the way Frank - GREASE is STILL your friend 8)