Crusader engine model 350 spark plugs?

[topseaturvy]

I'm changing my spark plugs and I'm trying to replace them with the best plugs. My engine is a 1985 Crusader 350 which is a 454 c.i. ( 11 meter Trojan) In a previous post here, about 10 years ago someone recommended the AC-MR43T. Some recommended the AC-MR44T. According to my 1985 manual the MR43T is for the 305 c.i., and the MR44T is for the 350 c.i. The recommendation for the 454 c.i. is Champion RV8C. Makes me curious why the recommend Champion for the 454 and AC for the smaller engines. On a post in The Hull Truth, one guy recommends Champion RV9YC, and other guy recommends RV12YC.

My usage is cruising at low speeds, and not pedal to the medal, so perhaps I could go with a cooler plug. But I just don't want to select the wrong plug

At the moment I'm running the AC-MR44T plugs. I replaced them once because that's what I pulled out. However as I just mentioned, those plugs are meant for the 350 c.i. I can see how the previous owner, as well as myself thought that they were the correct plugs because the engine model is a 350. ( meaning HP ) So when you glance at the spec sheet in the manual, it's easy to spot the "350" at the top of the column, then glance down to spark plugs and go with those particular plugs. However closer look shows they are talking about c.i. and not model number.

I should mention that both my engines are running the Mallory distributor "magnetic breakerless ignition" P/N 9-26306. I'd also like to replace the rotor and the cap, but I'm having trouble tracking down those two part numbers. Since it's not points and condenser anymore does that effect the type of plug I should be running?

[prowlersfish]

Sorry about taking so long to reply. the RV8C crosses to MR43T. The MR44T is close but 1 heat range higher. Why do they recommend Champion on the big block I have no clue, maybe a marketing deal? Mercrusier recommends AC MR43T on their BB of the same HP. The "Y" on champion and "S" means extender tip.

The MR44T being 1 step hot could be helpful with low-speed running. Have you looked at them and see how they are burning?

If it was my boat I would use the RV8C or the MR43T. I have always liked AC in a GM engine but that's a personal thing Coke or Pepsi?

Electronic ignition does not really effect the plug choice other than the gap sometimes.

Beacon Marine likely carries the cap and rotor.

[topseaturvy]

Sorry about taking so long to reply. the RV8C crosses to MR43T. The MR44T is close but 1 heat range higher. Why do they recommend Champion on the big block I have no clue, maybe a marketing deal? Mercrusier recommends AC MR43T on their BB of the same HP. The "Y" on champion and "S" means extender tip.

The MR44T being 1 step hot could be helpful with low-speed running. Have you looked at them and see how they are burning?

If it was my boat I would use the RV8C or the MR43T. I have always liked AC in a GM engine but that's a personal thing Coke or Pepsi?

Electronic ignition does not really effect the plug choice other than the gap sometimes.

Beacon Marine likely carries the cap and rotor.

Thanks prowlerfish. The plugs are black but not sooty. My mistake, the plugs in it are MR43T, not MR44T ( my misprint) I can't seem to find the AC plugs locally or on Amazon Canada. The Champion RV8C seem to be about 3 times as expensive on Amazon. Napa has the NGK crossover readily available across the counter so I might try them (BR6FS)
As you know by your contributing comments on my other post regarding Velvet Drive / Damper plate noise, I'm trying to see if it is an engine misfire first before pulling everything apart.

[captainmaniac]

Thanks prowlerfish. The plugs are black but not sooty. My mistake, the plugs in it are MR43T, not MR44T ( my misprint) I can't seem to find the AC plugs locally or on Amazon Canada. The Champion RV8C seem to be about 3 times as expensive on Amazon. Napa has the NGK crossover readily available across the counter so I might try them (BR6FS)
As you know by your contributing comments on my other post regarding Velvet Drive / Damper plate noise, I'm trying to see if it is an engine misfire first before pulling everything apart.

If you are trying to search amazon.ca I am guessing you are in Canada. Where are you located? I am in Burlington Ontario, and may have a couple of boxes of RV8C in the basement that I bought as spares YEARS ago for my prior boat (8 plugs each). Never opened. I would have to check them out and make sure I still have them and they look intact, but depending on where you are, and interest level, we may be able to work out a deal and get them shipped to you.

Geez this sounds bad, but they would have been purchased in the 1990's (does that make them antiques?)!! Somewhere between '93 and '99.

[topseaturvy]

Thanks prowlerfish. The plugs are black but not sooty. My mistake, the plugs in it are MR43T, not MR44T ( my misprint) I can't seem to find the AC plugs locally or on Amazon Canada. The Champion RV8C seem to be about 3 times as expensive on Amazon. Napa has the NGK crossover readily available across the counter so I might try them (BR6FS)
As you know by your contributing comments on my other post regarding Velvet Drive / Damper plate noise, I'm trying to see if it is an engine misfire first before pulling everything apart.

If you are trying to search amazon.ca I am guessing you are in Canada. Where are you located? I am in Burlington Ontario, and may have a couple of boxes of RV8C in the basement that I bought as spares YEARS ago for my prior boat (8 plugs each). Never opened. I would have to check them out and make sure I still have them and they look intact, but depending on where you are, and interest level, we may be able to work out a deal and get them shipped to you.

Geez this sounds bad, but they would have been purchased in the 1990's (does that make them antiques?)!! Somewhere between '93 and '99.

Thanks for that offer. I did manage to find a set of the RV8C's (8) locally at not a bad price. They arrive tomorrow. So hopefully they are the correct ones. Unfortunately counter people at parts stores these days don't know the difference between a spark plug and a drain plug, so I have my fingers crossed. But I still would like to replace the plugs on the other engine. Antiques you say, that's sounding expensive. lol! I'm about as far west as you can go in Canada on Vancouver Island. Hope you make it through that unbearable heat wave back there.

[captainmaniac]

Thanks prowlerfish. The plugs are black but not sooty. My mistake, the plugs in it are MR43T, not MR44T ( my misprint) I can't seem to find the AC plugs locally or on Amazon Canada. The Champion RV8C seem to be about 3 times as expensive on Amazon. Napa has the NGK crossover readily available across the counter so I might try them (BR6FS)
As you know by your contributing comments on my other post regarding Velvet Drive / Damper plate noise, I'm trying to see if it is an engine misfire first before pulling everything apart.

If you are trying to search amazon.ca I am guessing you are in Canada. Where are you located? I am in Burlington Ontario, and may have a couple of boxes of RV8C in the basement that I bought as spares YEARS ago for my prior boat (8 plugs each). Never opened. I would have to check them out and make sure I still have them and they look intact, but depending on where you are, and interest level, we may be able to work out a deal and get them shipped to you.

Geez this sounds bad, but they would have been purchased in the 1990's (does that make them antiques?)!! Somewhere between '93 and '99.

Thanks for that offer. I did manage to find a set of the RV8C's (8) locally at not a bad price. They arrive tomorrow. So hopefully they are the correct ones. Unfortunately counter people at parts stores these days don't know the difference between a spark plug and a drain plug, so I have my fingers crossed. But I still would like to replace the plugs on the other engine. Antiques you say, that's sounding expensive. lol! I'm about as far west as you can go in Canada on Vancouver Island. Hope you make it through that unbearable heat wave back there.

No problems. Hope those plugs work for you and you can find another set more 'local'. If you change your mind you know where to find me.