Spark Plug Gap for Roush 402 SR

[Got the Bug]

Anyone know what the spark plug gap is for a Roush 402 SR with an MSD ignition?

I've got a message out the dealer/installer who sold me the engine, but thought I would also post the question here.

[madmaxx]

Do not shoot me but why not give Roush a call. I have called a couple times and been forwarded to a tech guy, not the guy who usually answers. He always gave extremly detailed info on timing etc. I only wish I had his number but it was lost in an office move.

[DAVID GAGNARD]

MSD needs to answer that question.....spark plug gap depends on the spark plugs and the ignition system used.

David

[Rick Parker]

The Air/Fuel mixture inside the engine sure doesn't know what name is on the Valve Covers.

SPARK PLUG GAP
These examples are just starting points to get you going in the right direction. Every application is different and should be tested and tuned:
Compression Spark Plug Gap
Up to 10.5:1 .050 - .060
10.5:1 – 13.0:1 .040 - .050
Above 13.0:1 .035 - .045

PS: Be sure (don't guess) that the center button in the Distributor Cap is contacting the spring blade on rotor. Wider gaps are use to increase the flame kernal especially on a lean (emissions) type fuel mix.

[Tim Brewer]

.050 with MSD, and kind of like Rick said, it's really just a small block Ford engine with an MSD.

[PANAVIA]

Doug,

I would start them at .044 and give it a go.

Autolite makes a APP plug that should work in your setup. You may want to consult R' for plug spec.

depending on cam, closer (narrower gap) for better idle, wider for more power.

Like;

.035-.039 for a nice idle, runs out of juice at higher rpms.

.040-045 good idle, mid range, nice power.

.045-059 ratty idle , more power at higher revs, but will LUG at lower revs as the engine has "trouble" getting to the next spark. (depending on advance curve and cam)

This shows up as hesitation or missing going up a hill under part throttle from 1400-1700 rpm.

this also may be limited due to the R' cam. (BTW: what tune up specs do they give you with your R' crate>? BTDC,Advance, retard,vac advance >?)

Spark Away....

--Steve