Exhaust noise

[Dirtvet]

I just swapped in an HEI for the points distributor, and gained 350 rpm on the top end, but the biggest change was seat of the pants feel right out of the hole. The thing is, the exhaust started getting louder as the day went on. I checked for leaks but couldent find any. I'm running a log exhaust with the water going throught the logs before it goes to the engine, it kinda sounds like there is no water running throught them, but I know there is. At idle its normal but when it gets gas, it seems the left side makes a lot more noise. I don't even know what to start looking for to fix it, any advice?

[kp216]

Are you talking about the actual tone of the exhaust as it exits, or maybe a ticking noise that would indicate a leak?
Do you have water exitting the exhaust outlets when the motor is running? Water from your jet drive should go to your logs, then out of the logs to the front of the engine, then out the thermostat cover back to the risers where it exits the boat.

[Dirtvet]

Its the tone AND volume of the exhaust. Its not a ticking like an exhaust leak. The water pluming is run like you said and there is still water comming out of the exhaust pipes. The sound is more like a BLAP BLAP BLAP and as it got louder (later in the day) it sounded more like an ehco comming from a tin can.

[FASTRAT]

Its the tone AND volume of the exhaust. Its not a ticking like an exhaust leak. The water pluming is run like you said and there is still water comming out of the exhaust pipes. The sound is more like a BLAP BLAP BLAP and as it got louder (later in the day) it sounded more like an ehco comming from a tin can.
just my .02 cents....is it possible that the rockers are loose on that side?...with the additional rpm...they could have loosened up!...wouldnt hurt to ck them on both sides
fastrat

[sanger rat]

Change your oil. Could be getting broke down.

[mgar_red]

Just a thought, but you do now have more voltgage going to your plugs than before, resulting in a hotter spark. If either that, or if you advanced your timing, you may have cleared a bunch of soot buildup on the exhaust path with the increased heat as the day passed. It may have started breathing easier. But then again I'm probably wrong. :messedup:

[Oldsquirt]

Since you have through transom exhaust, you might just check to make sure you haven't blown out one of the flappers. Happened to me once and I was surprised the difference it made.

[Moneypitt]

Any change you made in the ignition, ie, the HEI, would affect the entire engine, not just one side or the other. It is very possible the timing curve is different from the point type to the hei, but it would be different for the entire engine. Make sure the dist is not loose enough to back the timing down. That would make it sound very different, but it would be both sides............MP
PS did you re gap your plugs???

[Dirtvet]

Thanks for all the info!
I will check the rockers, adjust them and upgrade them if they need it.
An oil change is way over due, it is on the to-do list, but I wanted to wait for the new dist. gear to break in, then go with some Mobile1.
I think the flappers are OK, but I'll double check them, as well as the rest of the exhaust.
Ill re-check the timing to see if it moved.
That should keep me busy for a wile, thanks for the help.