Lt1 383
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Teching In
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Lt1 383 The LT1 is basically a regular small block but has fuel injection and reverse flow cooling right?
So is the magnetic pickup on the crank that controls the fuel injection and the ign? Or can I use an older 400CID crank?
How does the Optispark stuff work anyway. Because it isn't waste spark ign and it isn't coil on ign. It has a cap and rotor but are they still driven off the Cam shaft? WTF?
So is the magnetic pickup on the crank that controls the fuel injection and the ign? Or can I use an older 400CID crank?
How does the Optispark stuff work anyway. Because it isn't waste spark ign and it isn't coil on ign. It has a cap and rotor but are they still driven off the Cam shaft? WTF?
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Joined: Feb 2003
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From: Bahrain
Originally Posted by GM_USER
The LT1 is basically a regular small block but has fuel injection and reverse flow cooling right?
So is the magnetic pickup on the crank that controls the fuel injection and the ign? Or can I use an older 400CID crank?
How does the Optispark stuff work anyway. Because it isn't waste spark ign and it isn't coil on ign. It has a cap and rotor but are they still driven off the Cam shaft? WTF?
So is the magnetic pickup on the crank that controls the fuel injection and the ign? Or can I use an older 400CID crank?
How does the Optispark stuff work anyway. Because it isn't waste spark ign and it isn't coil on ign. It has a cap and rotor but are they still driven off the Cam shaft? WTF?
The 400 sbc crank is large journal so it wont work on the LT1 unless it's ground down to the 350 journal size.
Any sbc crank with a 1 piece rear main seal can be used in an LT1, even 2 piece seal cranks can be used with a spesial adapter.
The optispark has 2 parts, a sensing part that produces 2 different signals to control spark and fuel, the second part is a rotor and cap just like a normal distributer. The opti is driven by the cam.
A regular rear mounted distributor in the older smallblocks is cam driven too just driven by the rear of the cam throwing another gear and extra slop into the distributors drivetrain.
A 400 crank can be used as mentioned by grinding down the hournals and using a 2 piece to one piece adapter, I know someone who did this and he says don't bother just get a one piece 383 crank meant for exactly this purpose rather than making something else work. Parts these days are a lot better than they were in years past a $200 aftermarket crank these days is probably stronger than the best one GM ever put in a 400 anyway and to machine the 400 crank you would be WELL over a hundred dollars probably an easdy $200 anyway.
A 400 crank can be used as mentioned by grinding down the hournals and using a 2 piece to one piece adapter, I know someone who did this and he says don't bother just get a one piece 383 crank meant for exactly this purpose rather than making something else work. Parts these days are a lot better than they were in years past a $200 aftermarket crank these days is probably stronger than the best one GM ever put in a 400 anyway and to machine the 400 crank you would be WELL over a hundred dollars probably an easdy $200 anyway.
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Thread Starter
Teching In
Joined: Nov 2005
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hey thanks for the help.
The 400 crank is a different crank because of the jornal size. That is why even on a regular 350 (witch is basically an LT1 but carborated and the coolant flows the opposite way) you have to get the jornals machined to fit the 350 rods. I have that part.
Opti Spark is driven off the cam like a regular destributor; however it isn't driven mechanically(I think that is what it is). So what drives the Optispark destributor?
The 400 crank is a different crank because of the jornal size. That is why even on a regular 350 (witch is basically an LT1 but carborated and the coolant flows the opposite way) you have to get the jornals machined to fit the 350 rods. I have that part.
Opti Spark is driven off the cam like a regular destributor; however it isn't driven mechanically(I think that is what it is). So what drives the Optispark destributor?
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