Thread: Correct Spark Plugs

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This is a question of ignorance and or lack knowing spark plugs heat ranges.
I have a sbc 350, 10 over with a crane cam #100172 218 int 218 exh at 50. I'm not good at Cam talk so if the 218 at 50 is confusing I gave the cam part # for reference.
The intake is a Edelbrock Performer RPM, with a 650 edelbrock carb, MSD ready to run dist 64 cc heads with 202/160 valves and headers.
The plugs that i'm using now are Bosch R3 Platinum 2. My question is? Is this the correct plug to be using and if not what would be recommended ?

The model and brand don't really mean anything, you need to konw the heat range. You'll probably be fine with the stock heat range, if not, you may have to go a step cooler.

not to be a downer on all the money you just spent on plugs.... but older v-8s tend to not like platinum plugs...... i've learned on my fords, they'll run better with good old autolites better than they will with bosch platinums

The Bosch multiple electrode plugs are a mixed bag. Ford 302's and Mercedez engines love them. They work fine in every other engine, but there is no performance advantage. They'll last a long time, though.

funny i've tried them before in one of my 302's and it ran like junk, put standard autolites back in and it ran like a dream again

I had a Chevy with almost the same setup,bosch accel Autolite OK but tried the AC Rapidfires ,they smoothed out the cams idle,picked up 2-3 mpg and were still looking good after 2years+ Bosch& accels would crap out after 3-4 months.

try Autolite 45s they will work fine. hotter plugs are a waste of $$$ when i got my MSD put in i (not knowing any better) asked for plugs that would 'burn hell fire red' the car wouldnt drive across my flat driveway without getting spark knock. i called up MSD and they said i had the wrong advance spring and bushing in the dist but that most of the problem came from the plugs. anything with copper will be good the best i have found has been the 45s

look at what the nascar guys run, and also my uncle used too run the southwest tour late models; he ran autolites in a 331ci baker engine (30,000-40,000$ motor!!). i think your best bet would be ac plugs in the right heat range- nothing fancy . dont waste your money on all thes wonder plugs, i think there junk.

Ok I think the AC rapid fires are what I will use, Should I use the stock gap specs of 32 ?

start with standard gap, widen it up a little try 37-40 and see how it runs..... if it seems to run a little rough gapped like that, narrow it up a little

Thanks for the info.

Originally Posted by Jim Standley

This is a question of ignorance and or lack knowing spark plugs heat ranges.
I have a sbc 350, 10 over with a crane cam #100172 218 int 218 exh at 50. I'm not good at Cam talk so if the 218 at 50 is confusing I gave the cam part # for reference.
The intake is a Edelbrock Performer RPM, with a 650 edelbrock carb, MSD ready to run dist 64 cc heads with 202/160 valves and headers.
The plugs that i'm using now are Bosch R3 Platinum 2. My question is? Is this the correct plug to be using and if not what would be recommended ?

Another thing to think about is the Platinium is a much harder and denser metal which make it harder for the current to go through them.
We run NGK plugs in about all the race engines dirt mod.,drag,street etc.
The cheap ones that sell for about $2.50 each.
I also have had good luck running the extended tip AC plugs with flat-top pistons.
I would call Edelbrock and see what they say.

I'll call Edelbrock and hear what they recommend, I think I will also give MSD a call to compare notes. Thanks Eric.

and also my uncle used too run the southwest tour late models

Hey lit549 who's your uncle, my brother-in-law has run that series almost from the begining to its last year(last year)
We run NGK's in the 355ci Watkins tour motor, no problems at all.
My avatar pic is the tour car at a Mesa Marin test 2 years ago.....

Jim,on my Chevy I was running an HEI & Accel Super coil ran the gaps @.040"