Spark plug choices

[Bradley Thornton]

Yes, if you change one change them all. You can always call Bakes they are a great place to call and get info also paying members get a discount.

[BlitzedVLX]

Yes, if you change one change them all. You can always call Bakes they are a great place to call and get info also paying members get a discount.

I emailed Bakes and they stated that the NGK TR55 Part #3951 will not work in my 320 LCR Indmar and they they only work for the 8.1L... but everyone on the crew says that is the one to buy so im confused?

This is what i received from bakes:

Either of these plugs will work. The AC Delco are pre-gapped; and the NGK need to be gapped to .045.

Qt. 8 spark plugs for a V8.

Thanks,

http://www.bakesonline.com/detail.aspx?ID=765

http://www.bakesonline.com/detail.aspx?ID=2168

[Bradley Thornton]

Same plug the #3951 is a hotter plug. Use my cross reference link and look at the Bosch as the number goes up it gets hotter.

http://www.angelfire.com/extreme4/skidoolympique/SPARK_PLUG_CROSS_REFERENCE.htm

https://www.boschsparkplugs.net/learning-center/article/225/heat-range-conversion-chart

[BlitzedVLX]

Is this the correct TR5 plug for my 2008 VLX Indmar 320 LCR

http://www.amazon.com/NGK-V-Power-Spark-Plug-Pack/dp/B000AUP640/ref=sr_1_1?ie=UTF8&qid=1394717990&sr=8-1&keywords=ngk+tr5

or should I go with the BPR6EFS that bakes recommends?

http://www.bakesonline.com/detail.aspx?ID=765

[Manga Boats]

Std NGK plugs that work in the Indmar 350 Vortec are...

If running a non vortec engine use the BPR6FS NOT the BPR6EFS as the thread is to long!

TR5, TR55, BPR6EFS, BPR6EF

Generally I use BPR6EFS for carb engines, PZ series for multipoint EFI and IX series for CAT based indmar 350 engines as its more cost effective for the customer to install plat/iridium for the later model engines. Plat seems to be a better fit for the EFI engines without cats as they don't run lean enough for the Irdium plugs

[nuttyskier2002]

David, it's a small block Chevy 350. Get a set of plugs that will work for it with EFI. I'm runnin the NGK TR5 and am very happy with them. No reason to order the expensive platinum ones as long as you are willing to change them every couple of seasons. I put on 50-75 hrs a season (average) and will most likely change every 2 seasons.

One caveat to this: The '96 and above L31 based engines use a different plug than the '95 and earlier engines. This is due to the vortec cylinder heads and their re-designed combustion chamber/compression ratio. 1996 was when the new Vortec 350 was introduced. So if your boat has vortec heads.......the '96 Chevy/GMC 350 EFI truck is the correct plug. If your boat is a '96 (or close) it might have the earlier heads as the marine industry tends to lag behind the auto industry by some time. If unsure what heads you have, count the number in intake manifold bolts that secure the intake to the heads. 8 bolts = Vortec. 12 bolts = earlier (pre-vortec).

[Nitrousbird]

One caveat to this: The '96 and above L31 based engines use a different plug than the '95 and earlier engines. This is due to the vortec cylinder heads and their re-designed combustion chamber/compression ratio. 1996 was when the new Vortec 350 was introduced. So if your boat has vortec heads.......the '96 Chevy/GMC 350 EFI truck is the correct plug. If your boat is a '96 (or close) it might have the earlier heads as the marine industry tends to lag behind the auto industry by some time. If unsure what heads you have, count the number in intake manifold bolts that secure the intake to the heads. 8 bolts = Vortec. 12 bolts = earlier (pre-vortec).

This is good advise, as 1996 is the last update the 350 "Monsoon / LCR" motors have ever seen from GM. The Vortec heads are basically a standard cooling flow copy of the LT1 heads.

[nuttyskier2002]

This is good advise, as 1996 is the last update the 350 "Monsoon / LCR" motors have ever seen from GM. The Vortec heads are basically a standard cooling flow copy of the LT1 heads.

Yeap! That is exactly right!

[BlitzedVLX]

Still confused...

BPR6FS, BPR6EFS, or NGK TR5 for the Indmar 320 LCR?

[Lance B. Johnson]

Just go with the bakes number. I am sure they have installed them in 100s of boats.

[Manga Boats]

Difference between the BPR6EF & S variant is the electrode tip is flat on it, but otherwise the plugs are identical, meaning it pretty much comes down to preference or whats available as you won't notice any appreciable difference. Generally recommended BPREFS for the carb and TBI versions

TR5 is a different heat range as it is a slightly colder plug than the BPR6EFS series and generally is recommended for the multi-point injected variant of the engine (LCR320 is one of these)

So to answer the question if you want to put a std plug in your LCR320 go with the TR5 but don't tear your hair out if you can't get them as the BPR6EFS plug will work pretty much just as well.

[BlitzedVLX]

Difference between the BPR6EF & S variant is the electrode tip is flat on it, but otherwise the plugs are identical, meaning it pretty much comes down to preference or whats available as you won't notice any appreciable difference. Generally recommended BPREFS for the carb and TBI versions

TR5 is a different heat range as it is a slightly colder plug than the BPR6EFS series and generally is recommended for the multi-point injected variant of the engine (LCR320 is one of these)

So to answer the question if you want to put a std plug in your LCR320 go with the TR5 but don't tear your hair out if you can't get them as the BPR6EFS plug will work pretty much just as well.

Thanks for providing this helpful information. I am going to order the NGK TR5 #2238 for my Indmar LCR 320

http://www.amazon.com/NGK-V-Power-Spark-Plug-Pack/dp/B000AUP640/ref=sr_1_1?ie=UTF8&qid=1394717990&sr=8-1&keywords=ngk+tr5

Edited March 18, 2014 by BlitzedVLX