Sidewinder, Here is my 2 cents on oil, and front tires ;
1'st of all I run my oil for the entire event, change it when we get home. We raced our JrFuel last week end in B/ND racing Comp at the Div 7 race in Sonoma Calif. We ran it 6 runs, 4 qualifying, and 2 elims. I guess I could re-used it but I've been dragracing dragsters since 1962, and have never re-used the oil. I don't know what kind and weight oil you use, but we use Motul 6100 10w-40, it's a synthetic blend. I have been told you don't want to run a full synthetic oil in an alky burning race engine, because synthetic oil and alky fuel are ester based products, so you will get too much dilution. The Motul has extra additives so unless I'm way rich, we don;t see any alky in the oil, [no baby puke]. Another team I help, drains their oil after each event also, and run the drain oil in their truck.
I know of a TAFC that uses a converter [ no clutch] and in order to get the idle low enough they run it very rich, they have to do that because the throttle plates can get stuck when adjusted that closed. So they cook their oil after every run to cook off the alky.
If you are running 50-60w oil you may want to set your clearances tighter and start using 10-40 oil. It takes power to push that heavy oil thru your motor. I only advise 50w oil if you are running nitro, mostly because you run larger quanity of fuel.
BTW, we have won 3 NHRA JrFuel Heritage Championships with my 10,000 SBC, and only broke one motor because of a bad trans, when the motor went to 11,500 rpm.
OK, now about skinny front tires, as far as I know Avon, or anyone else no longer makes a 2.75 or 3.00x19 rib tire. You no doubt want to replace your Avon's because they are cracking from age, and they might have stopped making that tire over 10 years ago. What I would recommend is sending me your 19" wheels and I can change them to 18" rims, then you could use new 2.50x18 rib tires. Ya I know the 18" will be a little shorter at 23" to 23.5" but you will be able to replace those tires. Plus it looks like, looking at your picture you can lower your front end and not have any clearance issues.
Feel free to call me with any questions, 800-624-3803, Hayden wheels,
Jon Hansen