Spark Arrestor Clearance Issue
 

After having new motors built for my 33 Fountain, I have an issue with clearance under the engine hatch. The motors are Dart tall deck, Dart single plane intake, 1 inch spacer, dominator carb. When all of this is under the hatch, I have about 2 1/2 inches of clearance. I do not want to raise the hatch.

Is there a "best" arrestor that will provide enough air flow? I currently have 10" round (K&N). I can replace the current element with a 2" screen. Would it be better to replace these with a long oval cleaner to gain more flow?

If I have to add more clearance, can I raise just the area above the arrestor without using scoops?

Thanks

Before I got my new boat, I was having a similar problem. I was going to cut a hole in the hatch and cover it with a piece of aluminum sheet formed about an inch high. That would give me 2 inches more clearence. Under the pads it would be almost unnoticable.

Lose the 1" spacer.
Stick with a 10" round, but go to the tallest you can fit. 2" of space from the base to the top is awful thin to make a smooth turn into a dominator. You'll lose more from the arrestor than you make with the spacer.

The perimeter area isn't your issue - it's the turn from horizontal into the vertical carb throats.

You can do what Patri suggests, and gain 3/4 to 2 more inches.

My buddy has a clearance issue on a 550" Hemi in a B-body Chrysler.

He ended up needing 1 3/4" tall filters. He is running dual 700's on a crossram. Dyno numbers were 914hp open carbs. 825hp with air filters on it. He added the K&N filtered "lids" instead of the top plate and went back to 880hp. This is a 1 3/4" tall filter on EACH 700 carb. You are trying only 2" on a DOMINATOR. Go for some more arrestor height.

Lose the Spacer
 

I asked the builder about the spacer and why it was added. He went into a fairly lengthy explanation as to why it is there (he doesn't have short answers for anything). The answer I took away from him was that the engine was designed with a set of components to meet specific objectives.

The carbs were sent to Nickerson for rebuilding and tuning. They came back $1600 later and Dean recommended that the 1 inch spacers be part of the assembled package. We did not know there was a clearance issue at the time or we would have told Dean to flow the carbs without the spacer. I think part of my height problem is also related to the drives. The boat has #3 drives that sit very high. I believe this also raises the entire package.

So if I go with a "filtered" lid, cut a hole and install an aluminum plate in the hatch, I can probably get 3 1/2 inches of arrestor height. Is that enough air flow to make the motors run the way they were designed?

Thanks for all the feedback.

I have these boxes on my PQ They give you a couple inches. I think CP Performance sells them. Not sure about you application but these may work.

It's true that #3's have to sit high. They're longer than a trs. Just switching from trs to #3 without raising x dim. will actually slow the boat down.