Tune up on 351?

I am doing a tune up on my 71 Holman Moody 351. Amazingly the spark plugs seem to be original from the factory since there is blue over spray on the plugs. The plugs are Autolite BTF3M, which is hard to find. Through my searching I found the below link that references old Autolites to the newer models/numbers. The replacement part for me is an Autolite 124.

Hope this helps in you search for the right plug.




Auto-Lite Cross Reference

Yea after listening to Chris and the others, I will stay away from NGK plugs.. I did some good research on them Autolite plugs, they show to be the plug..

79nautique wrote: 24 is the correct plug if your heads use the 5/8" plug and are a little newer, 124 plugs are the older style that is 13/16" plug.

Agreed. In my '71 Skier, I run the 45's- I believe theyre very similar to the 124's.

if you use a 5/8 socket to remove your plugs then use the 24's if you have to use a 13/16 socket then use the 124's

I believe if you have the gt-40's or even the p version it's a 726 maybe and a 5/8 shanked plug as well but the heat range is a little different than the 24's due to compression ratio's, Tim is more familur with those plugs so the number is a shot in the dark regions of my skull,, besides Tim likes to correct me anyway so i have to throw him a bone once in a while

skicat2001 wrote:    Your 79 Nautique I bet got the same 351 in my 85.. Right..

provided that you had yours balanced, a comp-cams, some head works and some other goodies to kick out 315HP then yes they would have been the same but mine was never a stock motor and I bet yours is.

for little more of a grand you can go the full H+C+I upgrade
heads, cam and intake...
600 plus shipping for a set of gt-40p heads from tristate.
265 for a cam research cam (In your case its a RR some price may vary)
200 or so for a new aluminum intake manifold...
an another couple of hundres for misc parts..bolts, gaskets, paint, etc...
Make sure your engine bottom end is in good shape..don´t want to end up with a rod pulling a hole in your new heads

It will take you engine to little over 300hp...

I did it and i´m quite happy..yet I´m still trying to sort some issues to take all the juice out of it.
Anyway I felt a drastic improvement in the hole shot and pulling. That may also be due to the fact I removed almost 500lb wet foam from the hull        

skicat2001 wrote: 79nautique wrote: 24 is the correct plug if your heads use the 5/8" plug and are a little newer, 124 plugs are the older style that is 13/16" plug. Hey Chris, All 351 Ford like the 78-86, dont they use the same kinda plugs. Same motors right.. When did they do upgrades to the 351 betweem then? Your 79 Nautique I bet got the same 351 in my 85.. Right..

All mid 70's and newer non-HO heads will take the Autolite 24's. The older 13/16" plugs are 124's or 45's. The HO (GT40) and GT40p heads both take Autolite 764's.

Like Kapla said, for $1500 you can add about 80hp over stock. Before crossing that bridge, its recommended you have a pretty good understanding on how your engine works and how to maintain it properly.

Note that the heads from triste are remanufactured, but are like new...
You can also find them cheaper on ebay, but may need lots of work and end up paying more than the trista ones...