Plugs and Wires for 502 Mag
 

What plugs and wires do you recommend for a '92 502 Mag carb'd (stock Gen V, I think)?

Bosch Platinum #1 and MSD 8mm wires is what I run....

MR 43t's is what I ran on a 93 Carbed 502, 600+HP

I have read on the board where some people have had good success with AC Delco Rapid Fire #1. Also, some have said you do not get much black smoke on transom with these too.

Thanks for the input guys.

jdnca1 - where can I get the MR 43t's? Who makes them?

Luv-n-it - I assume the Delco's can be had at any GM parts shop.

Do all the different types and brands gap to .040? Is there a difference in automotive plug wires vs. marine use? Should I use only a stainless steel bodied plug? ... so many questions for such a simple item!
Thanks again, Travis

KC baja
All the O'Rielly stores sell AC MR43T here in KC. That is what I run on my 540.

You should be able to pick the Rapid Fire #1's up at any part store (NAPA, Advance, Autozone...). My 502 EFI gaps at .040

You have iron heads on that mag motor so go with normal (not extended) reach plugs. Any auto store will carry them. Everyone has their own preference. I ran AC Delco MR43T until the dyno guy told me he saw a few of these blow out of the plug hole while running dyno sweeps. I have a good freind who is highly involved in Winston Cup racing and I checked out what plugs they run--given to them free as a sponsorship deal of course-- and they were the Bosch Platinum #4. So I went with the #1's. Just personal preference, just like oil and filters etc....

Best bet is to stick with MR43T, Rapid Fires (both AC Delco) or the Bosch Platinum series. Good prices, easy to find, well know....etc. Ask the junkie at the desk to look up the bosch plug comparable in temperature to the AC 43 if you choose to go that route. Have fun, LAter

Thanks guys for all the help!

Allan4 - your confusing me. In one line you say the MR43T's can blow out, then in another line you say stick with the MR43T's. What gives?

Anyway, I think we've narrowed down the plug issue. I've tried the Bosch's in my vehicles before with good results. I think I'll go that route.

Now about the plug wires. What is the difference, if any, between regular automotive and marine use wires. I've just replaced the stock distributor cap and rotor and need to complete the system. Does Napa/O'Riley/Advance and the like carry the marine versions or do they need to come from somewhere else?
As before ALL suggestions are welcomed.

Thanks.

O'Reilly carrys marine parts. Cheaper that the local boat dealers.

I run the custom (you make them up) Taylor wires got them in blue to match my hp500's. They seem to be MUCH better than the stock Merc wires. Ordered them through Summit.

Try a search for plug wire thread...
 

FYI - There were a couple of threads a few months ago that contained some in-depth discussions of auto/marine plug wires. Click on the search button, input "plug wire", and you will find them. Might be some useful info for you there. Basically, if you are running the stock ignition any decent quality 8 mm plug wire should work for you. A buddy of mine is running the Accel 8.8 mm wires, but he has an aftermarket Crane Hi-6 ignition that calls for a low-resistance wire. Keep in mind that the lower the wire's resistance, the hotter the spark that gets to the plugs. You might also check into the MSD wires - I think US1 Fountain is running those with good results. You should be able to find a good set of wires for $40 - $60.

KC, I guess it comes across a little confusing since I re-read my post. What I am trying to say is that everyone has there opinion about what is best. I had no problems what so ever with the Ac plugs. but, on trusted advice I switched. Having said that, I would be willing to be that over half of the boats on this board run the AC MR43T or MR43TS plug without incident. Just because one guy does not like them basically means very little. I went with the Bosch for both reasons I mentioned in the other post. However, most evryone will tell you that as long as you have the right temp and are using an extended tip (not reach, but tip) plugs you are going to see minimal, if any difference. Hope this clarifies things a little:D