What Sparkplug & Timing?

73-74 smogger, advanced cam, recurved duraspark, c6.

Run the timing up intil it diesels when shutting down then back it off till it doesnt.

stanger68 wrote:Run the timing up intil it diesels when shutting down then back it off till it doesnt.  

Dieseling usually happens because the throttle is open to much at idle;
that mostly happens when the timing is not far enough advanced.

I like the NGK Iridium plugs in the 7 heat range for that application.

rmcomprandy wrote:

stanger68 wrote:Run the timing up intil it diesels when shutting down then back it off till it doesnt.  

Dieseling usually happens because the throttle is open to much at idle;
that mostly happens when the timing is not far enough advanced.

I like the NGK Iridium plugs in the 7 heat range for that application.

Randy you are correct. I was thinking backwards. When timing is too high it will not turn over when hot. Regardless thats how i tune a basic engine. Run the timing as high as tollerable.

There are all kinds of different ways to set timing. Knowing your total mechanical timing and then total mechanical with vacuum advance applied is a good thing in my book to have/know. Without knowing the distributor curve setup makes it hard to give much good advice on the Initial Base Timing, in my opinion also.





https://www.summitracing.com/parts/msd-8985

The dizzy was recurved by Scotty.  Any comments running an Edelbrock performer & a Holley sniper in a 56 F100 ? Carb spacer ?

lathechips wrote:The dizzy was recurved by Scotty.  Any comments running an Edelbrock performer & a Holley sniper in a 56 F100 ?  Carb spacer ?

I would ask Scotty what he recommends.

With that said from the very limited information, If it were mine I would lean towards 40 total, with all the mechanical in, and the vacuum advance off and plugged. Then I would note what my base timing is, and test drive from there, especially a few WOT passes Without Vacuum Advance Hooked Up. If you run 93 octane you may get by with more then say 87. Trial and error is what you need to keep in mind. The Vacuum canister can be fine tuned on most with an allen wrench in the vacuum port hole for part throttle operation, ect.

Like I said if it recurved Ask Scotty, First,  Before messing with the vacuum canister.

Same with Carburetor T/B Spacers. Try a few see if it helps any. On a Carburetor it is good to keep the heat off the fuel bowl/bowls. Not as critical on most FI in my opinion.

Scotty seems to have made very good progress with his Ford Factory EFI Manifold and his Custom Carburetor Adaptors by making them taller. These are mainly just warmed over Truck engines, for Torque I believe, so bone stock may show less gain. Something to keep in mind, so give it a try.

PS: Do Your Home Work on that Sniper System. It's not all Cut and Dried on the Self Tuning. I was speaking more Towards Carburetor Applications.

https://forums.holley.com/forum/holley-efi/sniper-efi/38366-stock-ford-distributor-locked-timing