Originally Posted by heyjude076
I have a 364 nailhead with a 671 blower. It is a mild street motor. It has a YCM Mallory Distributor , MSD 6AL box w/in the car dial timing control. I managed to get two ¼ mile passes last year and the car pulled good the entire way. The PO said timing was locked and I did not pay much attention to that. I pulled the blower due to blower gasket leaking. I noticed that the distributor did not have any vacuum advance so I pulled it to check further. I found it has no mechanical advance. Guess that is what PO owner meant by locked. I installed the distributor exactly as it was pulled and then marked the custom steel hub for TDC. The engine fired on the first revolution, idled and ran fine. I checked the timing and it is 10 degrees advanced. With the blower and firewall it is impossible to reach in to loosen and twist the distributor for more timing and the dial in the car gives a max of 20 degrees. My question what effect is the lack of mechanical advance going have? I am leery about trying to make a full throttle pass with it now. Some have told me to run 33 degrees advance but I think this will make it difficult to start.
I would give it 22º-24º BTDC to begin with and work up from there- but I would caution against using anything more than 30º-32º max until you can verify there is absolutely NO detonation taking place. This means reading the plugs very carefully, as there can be detonation that goes unheard- especially when at the track w/loud exhaust from you and/or the car beside you- plus you're concentrating on other things anyway.
ANY "peppery"-looking deposits on the insulator is an indication you're in the danger zone, that's aluminum you're seeing
. Use the best available pump fuel for the street (if you can get E85, I would modify the fuel system for it ASAP), and consider using race fuel at the track for safety sake.
If you find it becomes difficult to start w/the timing locked in, you can use an ignition interrupter like you've seen NASCAR cars use. You trigger the starter w/o ignition, once the engine is turning over, trigger the ignition to start and release the temporary "ON" switch for the starter. There are other schemes for doing this, search here for more.
Another option is to use a distributor w/vacuum and mechanical advance and set it up to run w/an advance curve. If it was me, this is the approach I would take- especially if the boost isn't that high to begin with. BTW, what IS your boost or pulley ratio?
This all assumes the cooling system is doing its job and the engine isn't running hot to begin with- a hot running engine is much more detonation-prone and will limit the tune you can use.