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I know, I know its been done before; also transmission question

XJ6 & XJ12 Series I, II & III 1968-1992

I know, I know its been done before; also transmission question

 
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Old 08-10-2014, 10:02 PM
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Default I know, I know its been done before; also transmission question

Hello all,

After finding problems with my stock straight 6, the parts list price tag was far to great for a university student working part time. so I tried sourcing a new engine for it. My choices were either American or Japanese. I liked that the small block swap has been done before and that parts for that engine were relatively cheap. I also liked the idea of a Japanese I6 turbo engine, such as a 2JZ or RB26tt but those were more expensive to buy, and I would probably have to send the same amount on parts to get her running. Now I have the engine, 1970 z28 350 Small block, but i do not have the transmission. Im wondering what transmission would work well? I like the 700r4 because of the overdrive, (this would be mostly a daily) but th350/400 are more common and cheaper to come by. Now how much/how difficult would it be to rebuild one of these transmissions on my own? I like to think im slightly mechanically inclined so I think i could figure it out, but would it be to much money to be worthwhile?

Thanks
 
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Old 08-10-2014, 10:48 PM
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I don't know how hard a Chevy trans is to rebuild as I've never done one, only a Chrysler 727. I can't think it would be all that much different, certain mechanical and hydraulic principles should be common to all automatic transmissions, only the details might differ.

I have a 700R4 in my car (S-II) with its stump pulling first gear and 3.31 diff and I can't imagine anything else in a car as heavy as an Xj6. I think the S-III has 2.88 diff which would work even better with overdrive.

Find a repair/rebuild manual and see how involved a rebuild might be. Then you can decide if you want to try it yourself.
 

Last edited by Norri; 08-12-2014 at 02:42 PM.
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Old 08-11-2014, 09:55 AM
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Originally Posted by sunchip View Post
Hello all,

After finding problems with my stock straight 6, the parts list price tag was far to great for a university student working part time. so I tried sourcing a new engine for it. My choices were either American or Japanese. I liked that the small block swap has been done before and that parts for that engine were relatively cheap. I also liked the idea of a Japanese I6 turbo engine, such as a 2JZ or RB26tt but those were more expensive to buy, and I would probably have to send the same amount on parts to get her running. Now I have the engine, 1970 z28 350 Small block, but i do not have the transmission. Im wondering what transmission would work well? I like the 700r4 because of the overdrive, (this would be mostly a daily) but th350/400 are more common and cheaper to come by. Now how much/how difficult would it be to rebuild one of these transmissions on my own? I like to think im slightly mechanically inclined so I think i could figure it out, but would it be to much money to be worthwhile?

Thanks

700R4 all the way. These cars with a mild 350, 383, 406 engine, 700R4 transmission and 3:31 or higher gears are a joy to drive. 'Round here 700R4 are plentyfull and cheap. Most rebuildable cores go for 100 to 200 dollars. The TH400's and 4l80E's are really hard to find because the racers gobble them up.


Even if you already have an engine...the best and most economical way to do a convert is to find a early 91 to 94, LT1 based Cadillac, Buick Roadmaster, 9C1 police car, Impalla or Caprice. You can often find one CL between $1000 and $2000...Look for one with a good engine and trans that just cosmetically worn out. This way you can drive, test it and then swap it. This way you'll also have all the little things that add up fast, like the PCM, Alternator, power steering pump, AC compressor, intake, fuel system, Torque converter, fuse box, transmission etc. You'll also need to buy a conversion kit from Jaguar Specialties, Rams horn manifolds, drive shaft and a stand alone LT1 wiring harness. If you use this approach it a 2 weekend project after you remove the engine from a donor car.
 

Last edited by icsamerica; 08-11-2014 at 10:10 AM.
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Old 08-11-2014, 10:00 AM
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Here is an example.....


Chevrolet Caprice Classic Vagon LT1 $1695


Asking $1695. I'd test drive it make sure it's a solid runner and offer $1200 and pay up to 1500$. Even IF IF IF you rebuild a 700R4 yourself and are successful it will still cost 500$ in parts alone. Don't do it....you're not a trany builder. You don't know what you don't know. Do this instead. You'll never get 300HP and 24 MPG out of that ol' Z28 engine,. The LT1 / 4l60e combo will shift perfect, Idle close to a V12 and starts hot cold or otherwise on the 1st turn of the key every time.


If you don't have the money for the swap yet, buy the donor and drive it & sort it while you gather the parts and knowledge for the swap.
 

Last edited by icsamerica; 08-11-2014 at 10:15 AM.
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Old 08-11-2014, 02:23 PM
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Either listen to ICS, or buy my old (low miles) Jag straight six.
 
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Old 08-11-2014, 05:37 PM
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Stay 4.2L
 
 
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