holley 500 2 barrel. What jets?

[huntaaar]

i have successfully installed the holley 500 two barrel on my 305e but am having trouble jetting it properly. first i tried #72s and it was to rich(fouled the plugs) then i tried #63s and it was too lean(surged after take off) i currently have #66s and the plugs are honey brown like they're supposed to be. the thing is, the exhaust still smells rich. i just adjusted the lifters and tried every combo of idle mixture but it still smells rich and fuel economy is poor (10mpg). I this a poor carb choice? could it be my timing? is this normal? Any insight on this matter would be greatly appreciated. thank you.

[FetchMeAPepsi]

rich compared to what? These trucks don't have catalytic converters so they're going to be full force (dont run 'em in the garage )
you should go by what you can measure on the motor and not worry so much about the smell of richness unless she's smoking. Mne smoked like a freight train when i first got her running.
Whats your timing now? It should be 2UDC or 7UDC for manual or auto respectively

[huntaaar]

ok so its normal if she stinks rich a little. good to know. as for the timing, its an auto trans (th400). how do i set the timing or check it just to make sure its on? i have tried to learn how elsewhere but all the instructionals are done on a 350. if you have the time, could you explain to me what i need and what to do.

p.s. cecilia is a good truck name. mines name is "**** beast". not the most flattering but the name just happened last winter when i got stuck in someones yard trying to turn around in a caldesac. dug a 3 foot hole in the grass, dumped a quarter tank, finally regained traction and screamed "**** YOU **** BEAST" and the name stuck.

[huntaaar]

anyone out there ever heard of or tried to one of these "progressive" 2 barrel carburetors? its a holley/weber i think.

http://centralmich.craigslist.org/pts/3803469102.html

i guess one throttle plate opens at a time and they are supposed to be better on gas.

i hope im not annoying everyone cuz all i ever talk about is getting better gas mileage but dang... is 15 mpg to much to ask from these ol' thangs?

[FetchMeAPepsi]

Thanks for the name compliment I just saw it

No, not getting fed up with the mileage talk. Everyone wants to save a few bucks. Just be sure not to spend 10x as much as you'll save trying to do it lol.

I haven't tried one of those carbs but I have read that most mileage improvements are by changing the rear end gears so that you get faster umph with less RPMs. Of course it takes it off the bottom end though so if you use her as a truck hauling stuff or pulling bushes and trailers you might regret it a bit.

[donrm]

I have a 351E & put the 500 Holley on mine last year. They are right,you don't want to run it in the garage, mine seems rich also, but it sure runs nice. Had it on the hi-way the other day & it cruises great @ 60-65-MPH. I put mine on out of the box. Never adjusted it, I drive it. Besides electronic ignition 2 best things I ever did to the motor. Donrm 1966 GMC 8' fleetside p.s. p.b. &a/c Cinti oh P/S I contacted Holley they told me a 500 was too big! I listened to other
members. Tried & tested is the rule I follow. Thanks to the club.

[bigblockv6]

The Holley/Weber progressive carburetor was used in the 70's by Ford in there 2000cc and 2300cc pinto 4 cylinder engine, I think GM also used it on the Chevrolet Vega and Pontiac Astre. It's questionable how a carb like this would work on an engine twice the size of what it was intended for.

[Pete's 64]

Holly 500's normally have a 1/8 inch or so hole in each throttle plate.
This is to allow the plates to be at the proper position at idle in relation to the idle mixture slots on a 350 to 400 inch motor that idles at 750 or 800 RPM.
You may want to try sealing the holes with epoxy. This will allow the plates to be open further, and may improve mixture at idle. I am guessing that it is now OK going down the road, just at idle you notice it being rich.

[Pete's 64]

Oh on the MPG thing, if anyone has been able to get better than 12, please share the secret.

[randallgrunert]

I just installed a Holley 500 in my 65 and found that right out of the box my truck ran better than ever. I went from a top speed of 63 (GPS) with my Stromberg to 75 mph. I only ran this fast for a short time but all in all it runs great.