Gun5

iTrader: (37)

Well Iv seen with around 400 hp and MSD ignition 35-40? was leaning towards 35..

these are NGK TR55

Puck

iTrader: (17)

My very qualified tuner prefers and recommends between .030 to .035 for plug gaps. I had mine at .035 and now he wants me to go down to .030 on my next set.

Gun5

iTrader: (37)

ya I was thinking .35 for now and next set .30 and if i notice a bad/good diff go back or not

Gun5

iTrader: (37)

whats ur ignition

i got a 6AL, MSD wires, MSD Coil and MSD Pro Opti so i know im juicin it alittle more then stock

Puck

iTrader: (17)

OEM opti unit with MSD cap and rotor, MSD "Blaster" coil, and Taylor Thundervolt wires w/ tr55 plugs.

Gun5

iTrader: (37)

from what I hear any kind of after market box raises the gap about .5 because they juice it that much more like i said i was leaning toward .35 maybe

Formula350

iTrader: (3)

Stock coil puts out more in the higher Rs than the MSD ones

procharged355

iTrader: (13)

yea I would do .035 unless you are forced induction or nitrous

Formula350

iTrader: (3)

This dude says .050 unless you're running FI or NOS. Then you go .035

https://ls1tech.com/forums/showpost....21&postcount=1

Gun5

iTrader: (37)

hmm i sent him a msg

wrd1972

iTrader: (12)

Mine are set at .050" and I dont have N2O.

What is the reason you guys are going to .035" when OE spec is .050"?

Puck

iTrader: (17)

...yea, and then higher compression and rpms is supposed to make the cap go down again. Those rules are way back from standard SBC days, and the LT1 behaves a bit different.

The OEM specs arent always geared towards max power - hence the very modest timing and running pig rich from the factory. In most N/A high performance LT1s, especially in the higher rpms, you get more power and smoother response from a smaller gap in the .030-.035 range. The bigger stock gap tends to "wash out" under high compression and high rpms.

Then again, what credentials does my tuner have - besides being a personal friend of Ed Wright and working as a Chevrolet engineer since before most of us were born, and tuning hundreds and hundreds of TPIs and LT1s in the process .

I gained 35 to the wheels over a professional mail order tune with him.