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I have a 1984 that had the 231 Buick V6 with the Th200 3 speed. It has 270k miles and I am looking to swap the motor and trans. I live in CA and must meet smog requirements. Spoke with the Smog Ref and he told me what I needed to be smog legal, long story short, I pulled a 1991 GM 5.7l and the 700R4 trans out of a C1500, I took everything, computer, wire harness, radiator, Evap, etc... My question is...will this bolt in? I have new motor mounts no problem there, I am worried about the trans fitting in the tunnel and if the crossmember will work. (I am running single exhaust (has to have the Catalytic converter) so I don't think I need a double hump crossmember) and will the shift linkage work or do I need some kind of adaptors. Any insight is appreciated and resources to purchase needed components. Thanks Shack
 

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The only think that I can tell you is, the 700r4 should fit. There are lots of peeps here that put them under their Elkys. As far as everything else, I have no clue.
 

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yes it will all work and bolt right in,the big thing is going to be wether it idles in open or closed loop.if it is one that idles in open loop you will need to repin the injector wires at the ecm plug to match the car computer.no big deal . if you have an electric speedo you will need to remove the reluctor and speed sensor and put in speedo gears and an external speed sensor to keep your speedo working. all in all an easy conversion.the trans will clear the tunnel with no clearance issues. the trans crossmember will work you just need to shorten the mount pad to clear the 700 pan and elongate the mount slot.piece of cake,the shoift linkage will hook right up just use the bracket from your old trans that the cross shaft hooks to and you will be fine there. you will need to either get a efi elco tank or do as i did with the b body wagon tank .its in a thread titled efi tank
 

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i lived in ca. for 30 years and worked for a shop that did smog legal conversion.so if you need any more info let us know and i will chime in with any info i can help you with. its a very strait forward swap and i have done a lot of them
 

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Discussion Starter #5
Thanks

@CCC - Thanks for the info, big help. Didn't even think about the tank. As I go I will pick your brain if I have issues. Thanks again!
 

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I put a 700R4 in my '80. The mount distance for the 700R4 is the same as the TH-200 so the crossmember will be OK. You may need a new mount.

The driveshaft will have to be shortened 2". The driveshaft from an '83 C10 PU is a perfect length and spline. I don't know about a '91, though.

If you have the right shift arm on the trans, the linkage will connect, but you can't get it in 1st gear -- only P,R,N,OD,D, and 2.

Jack
 

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A truck powertrain is not smog legal in CA but you might get by with it. Most of it is the same as a TBI '91 Camaro. The xxxx747 ECM in the truck and the xxxx746 ECM in the Camaro are only 1 or 2 wires different in case you need to change it to pass legally. Forge ahead with the truck stuff; worry about it if they question it.

The 1984 will have connectors 7 and 8 pins long each. Find the "to the dash" wiring plugs in the harness from the truck and match up all you can. Then, figure out the ones that are unique. The park/neutral switch wire needs kept. The check engine light has a wire that leads to a lamp driver (kind of like a relay.) You can delete the driver and run it straight to the ECM. The ALDL wiring needs run; it'll be slightly different. The VSS from your speedometer can be kept and used to feed the ECM; the '746 and '747 are both 2002 pulse/mile compatible.

A taillight harness from an 85-87 TBI Camino can be used but it's just as easy to run your fuel pump wiring independently.

The driveshaft needs trimmed just under 3"

Hooker 2049 LG4 headers are probably discontinued like the 2050 L69 headers; Edelbrock still probably makes their L69 set. All are CA legal (but may require referee station review since they're not on a 4bbl engine.) The L69 headpipe and cat are a good step up from the LG4 stuff. Also, there are a lot of L69 cats that are necked down, whereas one for an '85 L98 Corvette fits exactly the same and isn't necked down.

83-89 Camaro speedo gears in the truck tailhousing are one option. Or, if you modified the tailhousing to keep the 40 tooth reluctor VSS and add speedo drive, you could wire the VSS through the truck's buffer. There are also VSS's that have a pass-through for the speedo cable/gear to hook up like normal.

If you give the ECM all the hookups as if it's in the truck and basically refer to an '89 Camaro for the things that "don't work", you'll have a fine running package. Closed loop is achieved at idle if the swap is done correctly. With regards to power, the '91 heads are poor for flow on the intake side. With doing swaps, it's better to get it running 100% proper "as stock," then worry about mods.

Enjoy the project and results.
 
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