Indexing small block ford plugs?

428tom · 07-13-2012, 07:57 PM

Is there anything to be gained from indexing small block ford plugs?If so ,is pointing the gab toward the exhaust valve the best?

Stephen & Horace Johnson · 07-13-2012, 08:58 PM

Quote:

Originally Posted by 428tom

Is there anything to be gained from indexing small block ford plugs?If so ,is pointing the gab toward the exhaust valve the best?

I've done it on my 331 and didnt notice ANYTHING..

buzzinhalfdozen · 07-16-2012, 11:45 AM

I've never indexed plugs as an attempt to increase power, mine will close up without it. I've read several tech articals on the subject each with their own set of results and reasoning for why it's best to position the gap either towards the Int. or Exh. valve. In MY opinion, if you were to index the gap more toward the Int. valve, where your fresh air fuel mix is entering you would have the best chance of igniting the mixture.Of course the combustion chamber design would have an effect on this theory. I've yet to actually see an improvement on the dyno or at the track that was measurable. Joe

Ed Wright · 07-16-2012, 01:41 PM

Plug indexing brings back memories of old straight plugs & huge domes that would knock them shut if you didn't.

Remember "fire slots"? LOL

Jim B · 07-16-2012, 02:47 PM

Quote:

Originally Posted by Ed Wright

Remember "fire slots"? LOL

Would I be out of line if I suggest you remember relieving a Ford block and using Johnson tappet wrenches? I'd go as far as to bet you're familiar with shortening the tops of the lifter bores for better access to the adjusting nuts......

Ed Wright · 07-16-2012, 03:01 PM

Yep, I raced a couple of flat heads too! LOL

FED 387 · 07-16-2012, 05:28 PM

more than likely the reason for indexing is to avoid contact between the ground wire and the piston thus closing the plug- on any engine--might be some HP value in doing that but probably insurance to avoid the contact----

07-13-2012, 07:57 PM	#1
428tom Junior Member Join Date: Aug 2010 Posts: 54 Likes: 0 Liked 3 Times in 3 Posts	Indexing small block ford plugs? Is there anything to be gained from indexing small block ford plugs?If so ,is pointing the gab toward the exhaust valve the best?

07-16-2012, 11:45 AM	#3
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Indexing small block ford plugs? I've never indexed plugs as an attempt to increase power, mine will close up without it. I've read several tech articals on the subject each with their own set of results and reasoning for why it's best to position the gap either towards the Int. or Exh. valve. In MY opinion, if you were to index the gap more toward the Int. valve, where your fresh air fuel mix is entering you would have the best chance of igniting the mixture.Of course the combustion chamber design would have an effect on this theory. I've yet to actually see an improvement on the dyno or at the track that was measurable. Joe __________________ Joe Buchanan SS/BX 3117

07-16-2012, 01:41 PM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Indexing small block ford plugs? Plug indexing brings back memories of old straight plugs & huge domes that would knock them shut if you didn't. Remember "fire slots"? LOL __________________ Ed Wright 4156 SS/JA

07-16-2012, 03:01 PM	#6
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Indexing small block ford plugs? Yep, I raced a couple of flat heads too! LOL __________________ Ed Wright 4156 SS/JA

07-16-2012, 05:28 PM	#7
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,416 Likes: 522 Liked 330 Times in 178 Posts	Re: Indexing small block ford plugs? more than likely the reason for indexing is to avoid contact between the ground wire and the piston thus closing the plug- on any engine--might be some HP value in doing that but probably insurance to avoid the contact----