Low Profile Flame Arrestor

I know this has been discussed before, but I have a few questions I havent found answers to. To fit my new intake under the motor box, I believe I will need a low profile flame arrestor. SkiDIM no longer sells the nice piece that some of you are using, but I someone mentioned Glen-L Marine and I found this one.

I believe this would work on my Holley 4160 since the airhorn size on the carb is 5" and this arrestor is 5 1/8", correct?

I need the breather for the tube going to the valve cover (oil cap). However, there's another smaller inlet on my current flame arrestor for the clear tubing running to my fuel pump. I havent been able to find a low profile arrestor that has this plumbed in. Is there anywhere else I can run that clear tubing to, or should the new flame arrestor be modified to add the fitting?

I havent had much luck finding other brands of low profile flame arrestors, and Ive been searching. The mallory you pointed me to a while back is still 2 3/8" tall and the wrong color It doesnt appear as though it has the fuel pump vent tube plumbed in either.

I searched some more and actually found some help with my own question. Jim In Houston ran into the same issue with a new flame arrestor in this thread. I dont know if my carb has the proper fitting on it or not, but its a possibility I could run the line there instead.

79, my point was that the Mallory's are taller than this one I found and still dont appear to have the fitting for the fuel pump. Obviously if it came down to it, anything that fit would be better than something that didnt!

I am pretty sure I will need the lower profile arrestor based on the intake manifold I want to run (Weiand Stealth). The Edelbrock Performer needs about 1.5" more clearance than stock, and the Stealth is almost an inch taller than that. I have approximately 2" of clearance on top of my current flame arrestor, so Im trying to be proactive about finding a solution. Once I get the parts on, I want to hit the lake!

Go REX marine ,com

The first thing I am going to do next time I see the boat is check to see if there is a fitting on the carb to run the fuel line to. If not, I have 3 options:

- Pick up another carb that has a fitting.

- Swap the fitting off my old flame arrestor to be used on a new low profile arrestor (if it can be done safely).

- Find a low profile flame arrestor that comes with the fitting. I have looked at Rexmarine and the one pictured below is the shortest one they have with a fuel line fitting. It doesnt have a vent hose fitting (to valve cover), and doesnt look any lower than my current flame arrestor (due to the neck).

All I did was wad up some duck tape and lay it on the flame arrestor and close the hood, how much was it smashed, here's the way I did it, el' hacksaw, cut the mesh down to what ever I needed and put the top or bottom back on with silver solder, it was on of those " couldn't wait" moments, I had just installed a aluminum intake.

I had the same problem on my 83 when I installed and Edelbrock manifold. It was about 3/4 of an inch too tall. I looked around and finally took a Dremel tool with a cutting wheel and cut mine down to size. Used some tape as a guide and reepoxied( this can't be spelled right) the base to the element. Works like a champ a diddn't cost a dime. You will probably need to use a shorter bolt in the arrestor as well.

Thanks 79, thats actually the same one I linked to in my original post- it appears we are back where we started!
I actually found one that is 2" tall with all the fittings here. You have to scroll down about half way and look for part number 3745649 for a Chrysler (short type).

Thanks to everyone for their input!

I thought I would bring this thread full circle. I found an arrestor on a boat being sold on ebay, and the owner let me swap with him. This is the same SS flame arrestor that SkiDIM used to sell as their "low profile" unit, but was discontinued a year or 2 ago. I discovered the same arrestor was also offered on several Nautiques in the mid-late 80's, primarily big blocks and for some reason, many '88 Ski Nautiques. I wanted this arrestor in particular because it was slightly shorter, larger in diameter, stainless steel, and had both fittings I need (5/8" breather and 1/4" fuel line).

It is 8" in diameter and 2" tall, with no neck- so the element is a full 2". The original arrestor on my boat was only 6.5" in diameter. It was 3" tall, with a 2" element and a 1" neck. I expect the new unit to flow just as well (maybe better?) due to the increased filter area. Best of all, I can now close my motorbox!

Before:


After:

Holy crap, it worked!!!!! Thanks for the posting tip BKH!!!!!!

TRBenj wrote: Theyre pricey too, at $15-20 ea.

I hear ya. What the hell isn't pricey from K&N. They have some good stuff though. Interesting about what the Donzi boy's think about 'em. Those are some Go Fast dudes so I would a$$ume they know what they're talking about.

Good question Doc. If you read anything into K&N's site, performance increases as the air is smoothed and turbulence decreases. Now I also understand that they're trying to sell product, but I've also read that same thing in performance books. Low profile air filters can normally (but not always) produce lower performance because the air has to turn a sharper corner to get into the carb and they generally have a smaller surface area for the air to get through unless you get a significantly larger diameter. This can be smoothed somewhat by installing a stubstack but really the best performance gains can be achieved with a larger diameter and slightly taller filter as a general rule (as it relates to carburated or TBI type applications). I'm certainly no rocket scientist though. That's why I really wanted to try one of these things if I could get one to fit under my engine cover. All I would need is another couple of inches.

boat dr wrote: I may be out of line on this question but here goes.... Install a high lift, longer duration cam ,taller and better breathing intake,GT 40 or good heads match the ports upgrade the ignition system,longer and hotter spark the list goes on and on.... Then i install a low profile flame arrester that does not list the CFM flow rate.How well and how much will this restrict flow??????       boat dr

Doc, I looked at a lot of marine flame arrestors, but never saw a single one that lists a CFM flow rate. Like I noted earlier, this arrestor was installed on many big blocks straight from PCM, so it shouldnt be overly restrictive. Although the overall height is lower, the filter area is larger than the one it replaces.

Raising the motorbox would interfere with the pylon, so that wasnt an option. Removing the 1" spacer creates another problem (where to plumb the PCV) and could potentially hurt performance as well. What other options should I have considered?

TRBenj wrote: Raising the motorbox would interfere with the pylon, so that wasnt an option.

TRBenj;
You might be surprised. The boat actually still gets a rearward cant when underway. Even though the rope may be even with the top of the motor box at idle, as soon as you take off, you would probably have a couple of inches to spare for raising the motor box if that's the interferance measurement that you're referring to.

TRB, the PCV can be plumbed into the intake ,you don't have to use that spacer.a simple fitting is all that is needed on the rear of the intake.Have done several with no problem.Chose to do away with the PCV on my stroker,just used two vented breather caps on each v/cover ran these to the flame arrester.Works great w/ no blow by....................boat dr