If you want it to be reliable for the race the most important thing to do is drive it now....a lot.
Obviously going though everything that has been mentioned in important, but get some miles in....like thousands of miles between now and then. Anything driven regularly will end up being reliable so long as parts are replaced as they are noticed wearing/going bad...really hard to ID these things when rarely driven. Get a feel for the truck, learn what isn't the best and fix them. Does it not start reliably/easily when cold, when hot? Do window seals leak in the rain, how do the wipers work in the rain, will it start in the rain(cracked dist cap, etc). Does the heater work(if you will need it to). A wiper motor that turns on fine may be weak/overheat/die under longer use. Can you drive with headlights on for extended times, does the switch get hot when you do? Are engine seals going to hold up to actually getting some miles in?
You can spend thousands upon thousands of dollars rebuilding replacing parts that are perfectly serviceable for many thousands of miles or test them out by use and only repair/replace what is needed. I opt for the second, I can't afford to replace parts that don't need to be and it's more fun to dive it anyway.
I drive my old stuff as much as possible. I've driven my 1951 International L190 wrecker from OH-GA-NY-VA during moves, it's still running on points. I've driven my 1960 International R190 pulling a loaded 45' trailer on the GA-NY-VA moves. The GA-NY trip the generator quit working, cleaned up some contacts and on the way. On the NY-VA move the rear seal went out and the clutch started slipping, had to replace seal and clutch to finish the move. It still is running on points. I fixed the muffler on the '60 R190 before the NY-VA move and ended up overheating an airline and having it blow out because at slow speeds up hills there wasn't enough air-flow for the direction the exhaust was pointing. Not too far from home the R190 starting backfiring, but ran great for the 1400miles before.....but it also sat for a year unused between moves....not my best idea(and yes we've moved a lot). I know some people claim to or actually have had problems with ethanol gas, but I haven't with any of my trucks in the time I've had them. And at 4mpg+/- my big trucks have sucked a lot of gas in that time.
Get to know your truck, what it needs, what it doesn't, learn how to set the timing, adjust the points, check for spark, learn how the brake system works, how the carburetor adjustments work. Get comfortable with the truck now and use it to the point where you have no second thoughts to hop it in and drive anywhere for the time leading up the the race....so you can just focus on the fun times.
And remember, despite what everyone says NEEDS to be updated on these old truck, when they were new they were DRIVEN not babied and they gave good reliable service. Farmers relied on their trucks to work, and they did work. If a family wanted to drive 1000mi to visit family or take a vacation in 1941 what did they dive, a modern car with disc brakes, abs, electronic ignition, electronic fuel pump, etc...of course not they drove a '41 or older car and for the most part would have done so without problems. Have you ever read grapes of wrath? Your truck is modern by comparison.
Tad
