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Discussion Starter #1
I'm thinking of heading down to a Test & Tune tomorrow and driving the car there. The track is about 40 miles away and I have to use money to fuel up the car to/from the track and then splash some race gas in there once I get there. This is where my question comes in, I have some Real Lead fuel additive left over from my other car and used it to raise the octane levels on pump gas. That car was an iron headed 355 with GM 70's heads though and now I have a 383 with aluminum heads & blower on top. I know the aftermarket aluminum heads have hardened seats to accomodate unleaded fuel, but will it hurt any of my parts (fuel pump, carbs, blower, valve seats, etc.) if I put the lead additive when I fill up in the morning instead of buying unleaded race fuel?

Trying to use what I got to save a little coin. This weekend's weather was supposed to suck and I was looking forward to saving a little money...oh well.
 

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shouldn't be a problem. lead was an additive that acted like an upper cylinder lubricant (kind of like marvel mystery oil). that's why manufacturers had to use hardened valve seats when the lead was removed from gas.
 

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Discussion Starter #5
So there shouldn't be any sort of wierd interaction with the aluminum itself or carb components? I just don't want to damage anything on my set up as I won't have the money to fix it.
 

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why do you need to run race gas or "leaded fuel" anyways if your motor makes 11 to 1 compression im sure that your highest grade pumpgas ( 91 or better ) will be fine just check the plugs after run to make sure everything is ok
 

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I've mentioned this before, but my quickest pass with the 14.5-1 engine was using a blend of a few gallons of Arco 91 with a splash of C-12 thrown in there--6.39/106.75.
I used several combinations of fuel depending on if I was using the bottle or not--usually it was pump gas and C-12; if squeezing I'd add a couple gallons of C-16. Mixing fuels was never a problem with anything. Now I run Arco 91 with just under 12-1 compression--so far it's run 6.60's/101, and still needs tuning for the low octane.
 

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Discussion Starter #11
I run race gas at the track to take away the chance that there could be any detonation under boost on the big end. I think around mid-summer I'm gonna swap the top and bottom pulleys to go from 3% underdriven to 3% overdriven. I may just borrow some 1/2" pulleys from my friend as he switched over to an 8mm pulley setup a couple years ago and has alot of left over pulleys laying around for me to play with at the track.

Best ET so far with the current set up on only about 5.5 - 6lbs. of boost is an 11.85 in the 1/4 at 116 MPH. Not bad for a little street car with only a 3.55 rear gear. I may just stay there as I really would prefer not to have a cage put in this car. We'll just have to see what the future holds as I have have definitely been bitten by the speed bug.
 

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not bad.............. well now i see why your worried about detonation seeing that a blower will raise compression if you spin it faster ( forcing more air into the cylinder ) waas wondering what compression ratio you have before the blower ( 8.5 to1 or more ). its fun when you get that speed bug yoo may want to find out how much a cage is going to be just in case. :yes:
 

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Discussion Starter #13
Compression is at 8.25:1 before putting the squeeze on it. I think I may have been hurting myself on Saturday by shifting too high. I think the sweet spot is gonna be about 6200-6300 RPM's after looking at the dyno sheets. I think on Saturday I might have been shifting at 6500-6800 RPM's. Hard to accurately tell when looking at the small in dash tach flying down the track. I think I'm going to spend a little money on the chassis set up this year and then over the winter start having the car tuned for more boost. I got plenty of time to keep going faster as I'm not getting rid of the car any time soon.:D
 
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