Sounds good, as long as you do keep the octane numbers over 100 and you continue to run this much compression & timing. I have another question. Every head manufacture whether they are OEM or performance have hardened valve seats on the exhaust side and as well on the intake side. I have to wonder why you would want to run lead in your engine. In my experience there is no performance gain to speak of and it will shorten the life of your plugs (especially if you like to run cooler than normal) The only reason why lead was refined in gasoline was to cushion the valve seats on the exhaust side of older non-modified heads. Some said that there was an octane increase with the use of lead but it was argued and in this day it is redundant. The use of marvel mystery oil was used to cool the valves too but using hi quality stainless valve has also made this practice redundant as well. You might want to thoroughly research this practice too because it has been documented that the use of marvel mystery oil caused a heavy build up of carbon deposits on the back side of intake valves. These chunks I have seen can be as large as a walnut and I don't have to tell you what this will do to your flow rate. Marvel Mystery Oil unlike lead (or diesel fuel sometimes was used) will breakdown due to the very high temperatures. It was this breaking down that would cause a large build-up of coked carbon deposits on the intake valve and port.

I would suggest that if your heads are built of high quality and using stainless valves the practice of using MM oil should be suspended.

Take care
Roby

Factory knock sensors are designed to listen to only a narrow band of frequencies. This frequency differs for some motors, and the sensor needs to be matched to the motor.

Then, some aftermarket flat band knock sensor transducers are not tuned to a specific frequency. The transducer itself does nothing to dampen or distinguish a particular level of sensitivity or frequency distinction - this is the job of the electronics in the head unit/display.

If you refer to needing to jump thru hoops to make a knock sensor behave properly in a closed loop system (like the current Merc offerings - or a stock automotive setup) then it is because those units have no built in provision for sensitivity adjustments. Aftermarket units (like the MSD and several others on the market) allow you to vary the sensitivity to tune it to trigger at a particular signal amplitude. In addition, the head units have internal frequency filtering circuits to make the unit "listen" only to specific frequencies. Some units are adjustable for that as well (not on the outside, but via internal pots).

My experience has been personally limited to BBC motors and I have used the factory GM transducer as found on the Corvette. It has worked well with the MSD sinal box.

A sensor may or may not be of assistance in this situation, but I would try it as if it proved to work, it makes short work of the rest of it...

I get goop buildup on the backs of intakes when I DONT run any oil in the fuel. It's the rare motor I see that doesn;t have some buildup there. I run a heavy shot of carb cleaner thru my motors on a regular basis (bikes, cars, boats). My 2000 5.3 Chev in the Yukon gets a sticky throttle plate every 5000 miles. Good ole carb cleaner takes care of that too.

I agree that leaded fuel has no advantage. I would ony run it if it were substantially cheaper for some odd reason. Makes plug readings all weird, too.

Thanks everyone for all the responses. I can get leaded 110 locally for $3.50/gal. I won't save much trying to cut it down to 102, so I'll just bite the bullet and run the 110 my first season with the boat. I don't want to cut any performance and definitely want the nitrous at the ready. During the following off-season, however, I intend to install a custom water-injection system. That should allow me to run 93 octane.

Sounds sweet Plum!! Don't forget the tunnel ram and dual quads!!

Oh, I haven't forgotten. I just need to give the wife a little time before I tell her an 82 MPH boat isn't fast enough.

It is common that some carbon burns and sticks to the back of the valves. However it is the oil that makes this carbon so hard that you can't clean with carb cleaner. I have seen instances to where they have to be bead blasted. Of course this measure is too extreme and valve damage will result. If it is built up this bad the valve needs to be replaced. Hi detergent gasoline can remove this stuff over time if its not too bad but for real thick build up will likely result in a burned valve because the carbon will not allow enough heat to dissipate.

And yes I can't imagine how you could get a clear plug reading when running fuel with high lead content.

Roby

Actually I think plug readings are quite easy with 110 octane leaded racing fuel. I have been reading plugs with this fuel for the past 10 years so that helps. There is still a fuel ring around the porcelins if the a/f is fat enough. If there is no ring developing within the 1st hour or so of running the motor is likely lean. At the drag strip we run a/f mixtures so lean there isn't a ring, but not in boats. There is a well defined heat line on the ground electrode which can be used to indicate if spark timing is too advanced or retarded. The center electrodes are easily read as well. If light detonation is encountered the aluminum speckles are very evident on the porcelins around the center electrode. White shiney areas on the center electrode are evident if pre-ignition occurs. Actually this type of fuel has additives to prevent excess depostis on the valves, piston tops, and spark plugs. Union 76 110 leaded racing fuel is what I have sued. Man this is the official fuel of NASCAR!! Now the 89 octane leaded fuel available in the 60's and 70's at the pump is certainly another story. In all honesty this racing fuel is the BEST fuel one could run in a high performance engine, too bad it isn't a little cheaper and available at the pumps on our lakes.

Been a long time since I've read a plug out of a leaded fuel motor. I guess the leaded fuels being used now are of a purity level of the ones I remember. Glad to hear it works out well.