Factory Plug Gap on Beefed up 4.3?
 

Ok, so my question is, when you change the engine displacement, does the plug gap change at all? I have a 4.3 TBI bored over .060, running flattop 350 pistons, mild Comp cam, MSD ignition system and distributor. ECM is chipped with Edelbrock chip, and running Venom injectors. If I did my math correctly, the engine is now nearly a 4.5L.

Most people who upgrade the ignition coil and components, tend to like a slightly larger gap. 0.040-.045 if I remember right.

ThanksI will try that on the next plug change.

My plugs are gapped around 40 from normal wear. Noticed a bit of a mid end improvement. compared to factory gap, but Ive got alot of mods done. They do look like they are running a bit hot though. I need to replace em anyways.

My engine was designed to throw all the torque in the mid and low ranges. Anyhow, shouldn't hurt to try 40 to start, see what kind of changes I get, and go from there.

If you wanna play with that #3 plug more then once lol gap em around 45. Drive it and then gap it at 40 and try again.

Number 3 is a breeze if you have a meter long extention. I do mine from the wheelwell amd its a snap.

ive actually got a tool for #3. its a t bone looking extension with a knuckle and a 5/8th socket attached to it. works great