350 or 500 cfm
- Thread starter 2Blew2B
- Start date
Howdy Steve:
What's got you at the end in tuning the 350 Holley? I tried to get a 500 working on my 250 without much success. wsa111 did some major internal revisions to get idle circuit and air bleed systems to work better. He was in touch with the Holley tech guys and used an aftermarket metering block with screw in air bleeds and power valve channel restrictions. Without a A/F meter reader it's tough. The top end was definitely better, but low end was sluggish and cruise mileage sucked. With my 3:1 rear gear and OD I could barely pull 7 lbs of vacuum.
Next I switched to an Autolite 2100 in a 1.33 size which is rated at 424 cfm, but has annular discharge venturi boosters for a better vacuum signal. I'm still tuning on it, but am not satisfied so far. Great top end, but still not as crisp at lower rpm. I've got a 1.23 2100 on the work bench for next. It is rated at 356 cfm. So far the 1.08 was the best all-around carb, but gave up just a little on the top end.
Don't overlook the Autolite 2100s. I haven't come across a Holley 350 yet so I'm no specific help there.
Adios, David
What's got you at the end in tuning the 350 Holley? I tried to get a 500 working on my 250 without much success. wsa111 did some major internal revisions to get idle circuit and air bleed systems to work better. He was in touch with the Holley tech guys and used an aftermarket metering block with screw in air bleeds and power valve channel restrictions. Without a A/F meter reader it's tough. The top end was definitely better, but low end was sluggish and cruise mileage sucked. With my 3:1 rear gear and OD I could barely pull 7 lbs of vacuum.
Next I switched to an Autolite 2100 in a 1.33 size which is rated at 424 cfm, but has annular discharge venturi boosters for a better vacuum signal. I'm still tuning on it, but am not satisfied so far. Great top end, but still not as crisp at lower rpm. I've got a 1.23 2100 on the work bench for next. It is rated at 356 cfm. So far the 1.08 was the best all-around carb, but gave up just a little on the top end.
Don't overlook the Autolite 2100s. I haven't come across a Holley 350 yet so I'm no specific help there.
Adios, David
Gene Fiore
Famous Member
I'm running the 500 Holley on my setup but I have a modified engine with 10.5 to 1 compression and 3.55 gears out back...see my signature for other mods. Throttle response is great and it runs lower et's at the track then when I had the 350 Holley on it. If you are running a fairly stock engine then the 500 would not be the best choice. What are your tuning issues with the 350 Holley and is it direct mounted or are you running an adaptor?
All,
Got the 500 bolted down and what a difference. No more sputtering, no more lag on takeoff or lag while shifting through the gear and the hesitation is gone. The power is unbelievable. The only problem I still have got goes back to another post I have out there, it is still hard to start. I repainted my timing marks and spun her around until they were almost lined up with TDC and pulled the disto cap and sure enough it was at the contact point for #1. (See timing post) but please continue the discussion on 350 vs. 500. Oh yea, I pulled the Holley right out the box, I made no adjustments except for the idle screw. I'm sold on the 500.
Steve
Got the 500 bolted down and what a difference. No more sputtering, no more lag on takeoff or lag while shifting through the gear and the hesitation is gone. The power is unbelievable. The only problem I still have got goes back to another post I have out there, it is still hard to start. I repainted my timing marks and spun her around until they were almost lined up with TDC and pulled the disto cap and sure enough it was at the contact point for #1. (See timing post) but please continue the discussion on 350 vs. 500. Oh yea, I pulled the Holley right out the box, I made no adjustments except for the idle screw. I'm sold on the 500.
Steve
Gene Fiore
Famous Member
Sounds like the 350 you had might have had some unknown issues...
