plug gap for 1988 OMC Cobra 5.7 carbureted

[ab59]

for the last two days I have researched what the plug gap should be for and NGK G-power---UR4GP plug for my new rebuilt 5.7 Carbureted engine. So far I have read answers from .30 to .40 . I am getting a little worn thin on how there does not seem to be direct answers for such a simple question . Not even the NGK site has this answer and when emailed they simply remain silent on the matter.
Does any one know what gap I should use on these plugs ? I am beginning to wish that I had bought ACs at least I would have some kind of an answer.

 

[alldodge]

Plug gap should be the same whether they are AC, NGK, Champion or any other. Have a look here and see if your motor is listed as the last line and .30 to .35 gap

http://www.maxrules.com/fixomcstern_specs.html

 

[ab59]

ok but I have a Mallory unilite electronic distributor , is the gap the same between the different types of distributor's ?

 

[alldodge]

Plug gap doesn't change with a different distributor. The plug and gap is determined by the manufacturing user (this case OMC) using heat range and plug type. The distributor is used to signal the coil when to fire, then it is up to the rotor, cap, wires and plug to do the rest

 

[bruceb58]

If you had a high enough voltage coil, you could theoretically jump to a much bigger gap but that would mean a completely different plug.

Out of curiosity, how are you getting your ESA system to work properly with this electronic distributor? 1988 boats came with points distributors.

 

[ab59]

As one Bruce to another I have not got a clue. This is the way I bought the boat. I will say this , in my youth I worked in a traveling type of job and I replaced 10 350 chevy engines in 12 years so I do know this little bit. One of the engines I bought from a wrecking yard and it had an HEI distributor in it so I just hooked up a hot wire from the dist. to my fuse box and used a circuit that came on and off with the ignition. This was all it took to to make the change but we are talking about a 1972 GMC pickup that was pretty basic and other that an egr valve no smog crap all over it.
About the plugs and gap , I measured the factory gap in these plugs being sold as for a 1988 OMC Cobra 5.7 to find the gap was 45 on all the plugs and so that is how I put them in the block. NGK says that they gap them at the factory for use in the engine that they are sold to be used in so that is what I went by .

 

[bruceb58]

Is your engine Vortec or non-Vortec? Are these even the correct plugs?

EDIT: Never mind..these plugs are short reach for a Non-Vortec head...you are likely fine.

 

[ab59]

I have a pre vortec engine. newly rebuilt with TBI 882 heads much to my dislike . Although they are TBI I had to buy an intake manifold to get from TBI to carburetor.
Guess this is not all that unusual but it was unnecessarily costly in my case but due to a crooked rebuilder it is what I wound up with.
The NGK plugs are sold on eBay for the year model 1988 OMC Cobra 5.7 and come with the gap already set to their recommendation.

 

[bruceb58]

Heads aren't really TBI or Carb. All the same really.

I looked at your other posts. When you finally get this thing running, you will have questions regarding the ESA and shifting. We will cross that road when you get there.

 

[ab59]

soon I hope , as tomorrow is test day . Is the ESA you are talking about the electric shift assist ? If it is then you are absolutely correct when you say I need to know because just like most of the rest of this I am willing but not schooled on much. I have a little mechanical ability but it has been twenty years since I did much of this stuff . After I bought a Toyota Tundra I have had no need for tools or repairs since 2002 so I'm a little rusty and I was probably just a parts monkey anyway because I can install a head but not rebuild one etc etc.
Funny at + 60 I'm still willing to learn whoda thunk it. lol

 

[bruceb58]

Where are you located? I thought I saw CA somewhere

 

[ab59]

yep- near Redding