CK5
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Working on MPG
- Thread starter 80' 427
- Start date
Lemme see what I have as far as metering blocks, I know I got a bunch, I believe I have one for the 4777 as I ran one of those. You can have it if you want, heck I'll pay to ship it to you just to see what the outcome will be.
I wish I woulda seen the post about the truck avenger. I never would have guessed that blocking. The hsab would have an effect on the Offroad capability of the carb. This is why so many people including myself chase ther asses on these carbs.. Great info thanks for posting!
I wish I woulda seen the post about the truck avenger. I never would have guessed that blocking. The hsab would have an effect on the Offroad capability of the carb. This is why so many people including myself chase ther asses on these carbs.. Great info thanks for posting!
I have the block that is original to the 4777 but the Pvcr is super small like .040. My David Emanuel book says if you use them for mpg to drill the pvcrs larger to .o46 or larger so you can jet it down. I figured the jet area of the pvcr and stock jet total area then worked backwards with the larger pvcr of the 750 dominator block and I get about .645 but I put in 64s for preliminary. I figured if I borrowed one with a larger pvcr large it would be the same difference. I actually have a marine one that is .068 or so that may get drilled and tapped so I can adjust it.
That makes sense, you want to be lean until the engine requires the enrichment.. Which obviously is the pvcr job to allow more in or out. The Pv is when that happens
http://forums.holley.com/showthread.php?16888-Holley-Truck-Avenger-670-CFM
Check out this thread. Seems to be a common issue.. for some reason I had no idea.. Im super glad you emailed them.. Im telling everyone I know to ditch these POS carbs.. they give holley a bad rap. My deal has always been a box stock 600 then modify that to work for crawling.. Adj fuel pressure regulator down to 1 psi for crawl and back up to 4 for normal stuff.. you can always run the floats a little low for extreme stuff, also vent flutes, foam (sometimes), the longest vent extensions you can fit, and properly dialed idle mixture and timing.. that usually nets excellent performance..
Check out this thread. Seems to be a common issue.. for some reason I had no idea.. Im super glad you emailed them.. Im telling everyone I know to ditch these POS carbs.. they give holley a bad rap. My deal has always been a box stock 600 then modify that to work for crawling.. Adj fuel pressure regulator down to 1 psi for crawl and back up to 4 for normal stuff.. you can always run the floats a little low for extreme stuff, also vent flutes, foam (sometimes), the longest vent extensions you can fit, and properly dialed idle mixture and timing.. that usually nets excellent performance..
Well since you're swapping carbs out, why not consider a qjet?
square flange only intake or I would. I don't like adapters, they leak and disrupt flow. Plus a holley parts are available everywhere and qjet adjustment parts are hard to come by. This hardly sees any off road besides a bad road or the pasture. My crawler is on LPG.
No, pretty simple. Bolt in tank, mount vaporizer, mount shut off, run coolant hoses to vaporizer, run lpg hose to shut off, then vaporizer. Decide on type of carb and install "sniffer" or carb. I went to a carb so I can only run lpg, it bolts onto a holley base plate. Run a the big vapor hose from the vaporizer to the carb. Wire the shutoff to key power. It will prefer more advance than normal and less total timing.
Mount to what?
Martin
Martin
That looks awesome! Good job, Also for ease of changing the air bleeds, remove the choke plate for now just to gain access easier, brass isn't magnetic so good luck with a chopstick and grease extracting one of those if you drop it lol..
The crossover tube is pressed in you should be able to get it out though. I'd have to check mine and see how it came out.. It's been a while.
So today I put my modified truck avenger on. The air bleeds were front .073 iab .035 hsab rear both idle and high speed air bleeds both .035. Ifr .030 jet 66 in front. Rear .035 76 jet. The front block is of a 500 cfm 2 bbl the rear block is from my 4777. So starting the day it was fat every where. First I reduced the front idle feed restrictor to .024 and the jet to 62. Still pretty fat. Like suggested sreidmx my rear idle feed restrictor was fueling the system. I opened the rear idle air bleeds first to .055 then .075 like the front now the a/f was getting closer. Finally I lowered front idle feed to .019. Now from idle to 1800 it is 16-15 a/f. At 2000 it gets fatter up to 14s the about 2300 it leans back down to 15s. I think the transfer slot and main circuit are overlapping so I am going to change the front high speed air bleed to .040 to help delay the main circuit coming on.
Pics?
Martin
Martin
