427 Engine rebuild - Page 2 - Impala Tech
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post #26 of 29 (permalink) Old 02-21-2020, 04:47 AM
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Location: Greenville, SC
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Agree with Dave. Look at Valvoline VR-1 mineral non-synthetic.

1968 Impala SS
496 Stroker
T56 Conversion
3.73 Posi-Trac
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post #27 of 29 (permalink) Old 03-28-2020, 08:39 AM Thread Starter
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Location: North Bellmore (Long Island) NY
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Update on the rebuild

Just had a meeting with the engine rebuilder. The block was decked (numbers saved) honed, bored, oil and water passages drilled,
main bearings installed.
The pistons and rods are bought and now we are discussing cam and compression, driveability issues.
Will keep you updated and will also appreciate any feedback during the process.
Thanks Guys
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post #28 of 29 (permalink) Old 03-28-2020, 07:01 PM
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I used to buy race gas by the 42 gallon barrel but after 9/11 I couldn't do that anymore. It is better to buy it in small five gallon cans anyway as it goes "bad" very quickly once it is opened. A better solution is additives that actually raise the octane of the fuel (not the small additives sold by the ounce in gas stations and WalMart but in one to five gallon cans that add whole numbers to your octane.

RACE GAS | Racing Fuel Concentrate

Once you have high octane gas available to you that you can find at any gas pump (you keep your additive in the trunk and add it as you fill the tank), then you can talk about your static compression ratio.

A stock cast iron head 454 running on pump gas has 7.4:1 static compression (with dished pistons). You want pop ups to fill the void of your 118-121 cc combustion chamber heads. My L-88 and LS-7 motors that I bought as service parts had 12.5 to 15,0:1 static compression ratios. With compression comes free horsepower.

That additive by the way is paint thinner. Well, it used to be paint thinner back before every one started using water based paints. It is Toluene:


Which causes cancer in people as well as laboratory mice (why we worry about mice getting cancer is beyond me; but most of the chemicals I handled warned me to keep it away from mice). It is a paint stripper so don't spill it on your car. It also evaporates as soon as you open the can (with a boiling point in the low seventies which means it is hard to keep around in Florida). But it is what the factory puts in race gas and doesn't contain lead.

You can still buy Tetraethyllead in barrels from Germany and mix it according to these charts to obtain any octane you want:

Octane Supreme Specs

or lead phosphate as used in the aviation industry in America:

Lead doesn't evaporate, but it is a cumulative heavy metal poison like Mercury that attacks your brain. Not to mention, once again it gives mice cancer, so don't let them breathe the gas fumes while you mix it.

And people wonder why I act crazy in my old age!

Big Dave

Last edited by Big Dave; 04-26-2020 at 02:39 PM. Reason: Spleling
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post #29 of 29 (permalink) Old 04-26-2020, 09:48 AM Thread Starter
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Location: North Bellmore (Long Island) NY
Posts: 23
just an update on the motor progression, crank balanced and polished, pistons machined for a 9.5 to 1 compression.
Ordered the cam (hydraulic roller rocker) to match my drivetrain ( turbo 400, 3:31 posi gears general cruiser).
Heads finished, hardened seats,brass bushings new seals. Almost ready to go back together.
Everybody stay safe, try to stay sane.
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