I've got an off brand flame arrestor on my 350 chevy with 750 holley and performer intake. It is about 5.25" od and 4" tall. It doesn't look like a very high flowing filter, and when I'm driving my boat (21' 1985 scarab) I can here the air whistleing through the arrestor at any RPM above 3000. I think that it's making this noise becuase of how much the air is restricted. I was thinking about taking the arrestor apart and pulling a few rolls of the SS mesh out of it and putting it back together. It appears to have an inner and outer layer of medium size screen, and in the middle there is a bunch of very small mesh. Can I just pull all of the small mesh out and keep the medium sized mesh? A few more dust particles may get through the filter, but it should flow a bunch better. What do you think?


Thanks for all the help, this board is great.

Before you mess with it, check to see if its restricting flow. Run the boat WOT with the arrestor and then remove it and see if the RPMs increase at all. If they do, then I would say to get a K&N for a $100.

I'll definitly run it with the filter off to see if it is really restricting the airflow. But I'd rather pull some screen out of the filter I've got now and save the $100 for gas. Do you see anything wrong with pulling some of the screen out of my current flame arrestor? Will it still be a flame "arrestor"?

I did what you are talking about and I picked up about 100 rpm. The mesh is pretty thin now and it probably won't filter as well, but it is pretty clean on the water and at least big stuff can't enter the motor. Just make sure you run your blower before you start your motor. Doing this probably limits its ability to work as a flame arrestor. Mine is a 3" X 10" gaffrig on a 1050 Nickerson. I removed about half of the smallest mesh screen. If you shine a flash light on it you can see the stud that holds it on the carb, so you know it isn't very restrictive.

i had a blower motor at 762 hp with 2 gaffrig 5X8 it lost 25.7 hp on dyno, i have heard they take a few layers of screen out, using a single or 2 lawer of screen less restriction ,want help on flame thru, but cost guard cant tell

Well I decided to just get a K&N flame arrestor instead of messing with my stock one. The boat gained about 200 rpm's , but now I've got another problem. Before when I would make a high speed WOT run and then stop and check the plugs, they would have the perfect light brown color. After I put the K&N on , I wanted to do the same think, well I did and the plugs are bone white with just a high of tan color to them. I guess all the extra air that the motor is sucking in made it run a little lean. Is it OK to have the plugs white with just a hint of tan, or should that be a solid light brown? If I need to richen up the carb a little (4160 Holley 750 vac. secondary) how do I do it since I have no secondary jets? If I go up a size on the primary jets, won't that affect the mixture at cruiseing speeds? Do I need to buy one of those aftermarket secondary metering blocks (the same that comes with the double pumpers) with jets in it for my 4160?

Try raising the float level in the secondarys just a little. This may solve your problem without buying the secondary metering block.