AuroraGirl
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Nice
8.1 vortec into 1979 k30
- Thread starter Lu Blunt
- Start date
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ma3600vz
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there is a option to go old school with the 8.1 but it is just as expensive as the mall amount of aftermarket stuff for the efi system
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ma3600vz
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if the sm465 will not hold up time for a nv4500
AuroraGirl
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What do you mean? Like youd prefer to use a NV4500? Or that it couldnt handle it? I think the SM465 could handle it fine, but it would be more work just on the transmission to engine side of things, rather than the floor/ fitment side of things
ma3600vz
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yes I am a big fan of the 91-94 nv4500 I saw a post forget what number it is that said he could tear up his 465 and a 4l80e was recommended that is also a good option imho I do not know how much the 465 can take I think it could take it just fine but if some thing dose go wrong I think that the 4500 would be a good way to go
AuroraGirl
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does a 8.1 have a Gen III LS bellhousing?
If it does, the early gmt800 had option for manual transmission (6.0, not sure about 8.1) , so id use that simply for its designed to fit eachother already. If it doesnt already match , then I would say go to the nv4500 because of gear count and shifter quality
The Sm465 is a very small stout unit, but the shifter is weak point and needs custom fixes to get not feeling like your rowing a boat
The sm465 is also known for falling out of 3rd gear, needing gl4 lube to not attack the brass synchronizers or whatever it is that GL5 isnt friendly to. While its a classic, youre already going through the work to put a fuel injected 8.1, might as well give yourself a fighting chance for any fuel economy and allow your torque to be used to fuller potential.
Now if you want to use an Automatic.. .you have an engine thats designed to mate to a 5 or 6 speed allison from factory!
ma3600vz
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google says that the 8.1 has a the old bbc bellhousing pattern
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AuroraGirl
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well thats a shame
Lu Blunt
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The space between the 8.1 and the firewall is tight but not impossible. To me it looks easier to replace crank sensor in the squarebody than a gmt800. I installed a new acdelco crank sensor with anti seize while the engine was out. Also did egr delete and adapted the oil pressure sensor to use the squarebody sensor and gauge
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Lu Blunt
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The aftermarket Dart intake to run a carburetor is a cool option but the intake is always back ordered and sells out immediately. Also lots of guys scamming people online saying they have one for sell. I’m looking forward to the increased drivability gained from fuel injection.
The nv4500 would be a nice upgrade for overdrive but it’s not exactly budget friendly. Nv4500 aren’t cheap. I would need convert from mechanical to a hydraulic clutch setup and get the correct bellhousing. Possibly modify driveshaft and trans crossmember. Account for the difference in shifter location. Also the transfer case would need a 32 spline input shaft and adapter kit. That’s just what comes to mind. Allison transmission would be badass but that’s even more expensive.
The bell housing bolt pattern for sbc/bbc will work with ls motors. The LS Gen III/IV motors have 6 bolt holes. Unlike the sbc/bbc the very upper bolt is cast n drilled and used. The upper R/H bolt if looking at flywheel is undrilled and not used on the LS. It can not be drilled or you will hit the cylinder. The big difference between LS and old school sbc/bbc is the crank offset of the Gen III/IV motors is .400 intoward the crank. So to make up for this GM used a long thick flanged crank for some very early motors. Later around 2000 GM went to a common crank spacing and used with a dedicated flywheel with correct spacing. This means a sm465 to an LS motor requires the advanced adapters $800 kit in order to use the LS oem flywheel and clutch kit. The 8.1 being old school setup means no adapters to use the oem 8.1 flywheel and clutch kit.
The nv4500 would be a nice upgrade for overdrive but it’s not exactly budget friendly. Nv4500 aren’t cheap. I would need convert from mechanical to a hydraulic clutch setup and get the correct bellhousing. Possibly modify driveshaft and trans crossmember. Account for the difference in shifter location. Also the transfer case would need a 32 spline input shaft and adapter kit. That’s just what comes to mind. Allison transmission would be badass but that’s even more expensive.
The bell housing bolt pattern for sbc/bbc will work with ls motors. The LS Gen III/IV motors have 6 bolt holes. Unlike the sbc/bbc the very upper bolt is cast n drilled and used. The upper R/H bolt if looking at flywheel is undrilled and not used on the LS. It can not be drilled or you will hit the cylinder. The big difference between LS and old school sbc/bbc is the crank offset of the Gen III/IV motors is .400 intoward the crank. So to make up for this GM used a long thick flanged crank for some very early motors. Later around 2000 GM went to a common crank spacing and used with a dedicated flywheel with correct spacing. This means a sm465 to an LS motor requires the advanced adapters $800 kit in order to use the LS oem flywheel and clutch kit. The 8.1 being old school setup means no adapters to use the oem 8.1 flywheel and clutch kit.
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ma3600vz
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while I do not have any idea what a some one would say a ''good'' price for a 4500 is I have to ask is just under 2400 really that bad for a reman unit yes you have to get a bellhousing and a shifter unless you a ready have them https://www.summitracing.com/parts/zud-rmt4500c-2
AuroraGirl
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Also an option
Tremec makes new units that can be used in the same way, and while its pricy they are new and they sell direct fit bellhousings for the 8.1 even.
6.16 low gear ratio is nice
.76 overdrive
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Tremec makes new units that can be used in the same way, and while its pricy they are new and they sell direct fit bellhousings for the 8.1 even.
6.16 low gear ratio is nice
.76 overdrive
AuroraGirl
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Pricy lol
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When I was looking at those in the Tremec booth at a show, there was something goofy about them that made it not ideal for a GM application. I don't recall if it was the input or output... it might have been a 29 spline output or something.
They may offer more options now. I'm sure it's not very affordable though, to the average fella (or fellette) that's installing a used engine.
