SB

iTrader: (1)

Larger cammed motors need a lot of intitial advance. If they don't get enough advance, they will also exhibit the symptoms your having.

#1 rule when tuning carburetors is:
Make sure your ignition is correct
Make sure you don't have any vacuum leaks
Make sure your valves are adjusted correctly
Make sure you have correct compression in all cylinders
Make sure you have proper fuel pressure
Make sure your flame arrostor top is not touching/ or almost touching your choke tower. 3" or more is good.

Then, go tune your carb if this still seems like the culprit.

wingnit

Talk about information overload........

The problem it seems is that there are now too many cooks in the kitchen............many of which don't understand the workings of a Holley. But hey, It's your money they are spending. I am now done posting in this thread. Good luck.

BTW...the info posted by SB above my post (post #11) is good info.

motor

iTrader: (3)

Anytime someone posts a question on an open forum ,there will be replies from people with varying knowledge of (whatever) .I don't call this too many cooks ...I call it input .You've hopefully got enough sense to sort out truth from fiction .Not many "cooks" yet on this short thread.....Certainly you don't think your point is the only one that matters. .I'll go make another drink .............

MichiMike

If all else fails buy a new carb...been there done that.But bad performance can be so many things.

wingnit

I certainly don't think my point is the only one that matters. I am certainly always willing to learn new things. I am certainly very open minded. I certainly know when to back away from the keyboard. I most certainly have enough sense to walk away from this thread.

turbo2256b

iTrader: (1)

http://www.nickersonperformance.com/ Usally tune my own carbs but set ups like my dual quad engines send my carbs here to make them identical.

CDShack

Nickerson is Great, but I don't think he's there yet.
SB, all great info as usual! I was leaning towards this being a new condition, kinda of everything was fine then "suddenly went fat" and leading him to the simplest/fastest fix with the facts he gave. All the procedures you sited should be followed up on in this situation, even IF the carb PVs are the problem, and especially if they are NOT the problem.
Performance, keep us posted!

performancems

It's a new boat to me, and this is the first time I have had it in the water. It's complicated to be a mechanic over the internet to somebody that's not quite sure what they're doing. I appreciate all feedback and suggestions. I've never worked with a holley before, and the cheap rebuild kit I got from advance didn't have all the parts match what I took out of mine, so I reused a few things, including the power valves. Just found a guy down the street that had the right size ones in his spare parts drawer, and they feel much better than mine....one of them actually felt stuck. Timing is the next thing I'm doing, but being a gen VI motor there aren't timing marks like i'm used to, so my old timing light does me no good. I'm taking it to my buddy this afternoon or tomorrow to have him do it for me. From what I've gathered from google, I should be at 8-10 at idle and advance to 30? does that sound right?

CDShack

8-10 idle is good, makes them easy to start. My experience with naturally aspirated BBC is they like around 34, give or take. More timing isn't necessarily more power. Last BBC carbed motors we dynoed maxed at 36 degrees and started losing HP any higher.

turbo2256b

iTrader: (1)

You shold get all your parts from Quick Fuel. If its an older carb it might not have back fire power valve protection. QFs stuff is much stronger and they have retro fit anti back fire kits. Just installed them in a 830 I have for sale complete rebuild using QF parts.