Best plug for LT-1

[John Nechiporchik]

Thanks.

[Dan Fahey]

Bosche Platinum 4 Prong Plugs...

[John Nechiporchik]

Dan, Advantages??

[Ed Wright]

Originally Posted by Dan Fahey

Bosche Platinum 4 Prong Plugs...

Another plug I have seen too many problems with. Ditto mis-fires, sorry I meant split fires. E3 are also problem prone. I have found no "trick" spark plug that makes more power than an AC, Champion or Autolite. Motorcraft plugs are good too.

I owned & operated an extremely busy & successful performance tuning shop for over forty years. Probably sold & installed more spark plugs than most here. Autolite & Champion have, in my experience, been more reliable that any others. I have had ACs with open resistors right out of the box. Look like a bad plug wire on the engine analyzer's 'scope. Zero issues with Champion, Motorcraft & Autolite.

You may have a good set of those plugs, but I have seen enough bad ones I would never recommend them.

[Dan Fahey]

Originally Posted by John Nechiporchik

Dan, Advantages??

These are my observations using Bosche 4 Prong plugs.
My engine is an Iron Head LT-1 and many of our Impala and Vette Bloggers have had zero problems.
Some go back to copper plugs and work fine until the tip wears out.
Blower or Turbo guys use just about all of them with good success and have their preferred set ups.

My experience is that Bosche Platinum last forever...though 4 prong more expensive.
Use them on all my cars and look perfect every time they are checked.
Our Impala guys retrofit the GM 8 Coil LCCC from the LSx Series to get rid of the Opti and add Accel or MSD Coils.
I have just the one MDS Coil replacing the Stock one and carry extra Opti Harness.

The 4 Prongs are spaced perfectly apart which attract a clean Spark.
Prongs are vertical and should reduce flow restriction over a L shaped Prong.
Never had to index them for better performance.
OR
Drill a Hole in the Tip like on a L-shaped Prong to prevent blow out..

Bosche makes a 2 Prong..
Figure 4 prong reduces a touch of combustion chamber volume.


D

[Ed Wright]

Dan, you may be over your head here. Most everybody knows you do not use platinum plugs with a blower or turbo.

[Bill Grubbs]

Dan,
What gap do you run, and what is the procedure for setting it?

Bill

[Dan Fahey]

Originally Posted by Ed Wright

Dan, you may be over your head here. Most everybody knows you do not use platinum plugs with a blower or turbo.

DID not say that.. !!
Stated our community of our B-Body Clubs and ECIRS and ISSCA Racers were using just about everything with success.
They have their preferred set ups.

Got years of ImpalaSSforum details to back me up..

D

[Dan Fahey]

Originally Posted by Bill Grubbs

Dan,
What gap do you run, and what is the procedure for setting it?

Bill

I do not gap the Bosche 4 Prong.. Just visually check them for defects.
Have measured them before and consistently have the same gap from the box.
Only time they had to adjust one is when it got dropped and bent a prong.

It has always been a quality product no maintenance plug.
They are built to German Standards.

In fact replaced them when I rebuilt the engine but kept them as they were in perfect condition.
Put them in my 1994 Caprice SSuperWagon at 145,000 miles and now have 205,000miles and purrs like a kitten.

Dan

[SuperStock 1890]

We use the Rapid Fire #3. Never an issue.