Im going 2 the track this thur, and i want it 2 run at it's best! For a rebuilt 164,000 mile motor that is........ O and by the way Just how much does having 9:5:1 comp.ratio in these motors help me? or hurt in long run???

 

If your engine doesn't ping under load with low octane fuel, going to a higher octane won't do anything for performace. It will make your wallet lighter. The only way to know if it will help is with a scan tool to see if you're getting any knock counts. If the computer detects knock, it will retard the timing and decrease performance. Going to a higher octane doesn't really help performance. It just keeps the computer from lowering what's already available.

My daily driver truck gets better fuel mileage with 89 octane than it does with 87 but I haven't calculated if the increased cost of fuel offsets the increased distance I can travel. Using 91 or 92 doesn't increase my mileage any more but I only fill with that when I want to use my NOS.

With 9.1 compression ratio, 91 or 92 octane pump gas should be fine. You could try some 100 octane unleaded race gas just to see if it makes any difference. Don't use regular leaded race gas. It will kill your O2 sensors.

 

She does ping, but only when i throw her in second and really lug the motor...
By the way there are no more o2's on the car im all motor no elec crap cause the guy before me nigg,d it all up excep 4 the HEI i left that, i didnt want vac advance i heard it was not as good

 

You could run race gas and advance the timing but I wouldnt recommend it. Just spend the cash on other mods which are more permanent.

BTW mine is also a 5.0 HO (1984) with a 700R4 and mine used to ping before I got it tuned up right. I got a new distributor and tuned it up and it went away.

 

I missed the part about it being an '84 so it wouldn't have all the electronic stuff.

Is it pinging with premium pump gas or just regular 87? If it's pinging with the premium then some race gas would probably help. You can do a mix. 5 gallons of 92 pump gas plus 5 gallons of VP C12 (108 octane) will give you 100 octane.

C12 is the most popular racing fuel so it's probably the cheapest.

www.vpracingfuels.com

 

Not only did 84's come with ECMs (all domestic 3rd gens did), but the carbed 305 HOs (L69) came with knock sensors. Your Canadian carbed cars were not ECM equipped.

 

I will have done it all event, This one's with me till i give it 2 my son/daughter wichever 1st

 

Yep, my '84 came with a computer harness that connected to the carb(cost me like $300 for a new carb) and knock sensors that barely worked