If I drop the 700R and go with a 350 where does the speedo cable go. I have a 87 Formula, recently did a engine swap, 305 - 350. Now the trans is slipping. When the swap was done he was supposed to put in th350 and stall converter and he sold both. Also sold my trans and stuck in trashed one. Going after 350 but need to know what I need to get speedo working.

 

I've never owned a 700R4, but if your speedo is cable driven, then it should be able to plug right into the receiver on the Th-350. I'm not totally sure about this, but I'm fairly certain your 87 is not gear driven. Most cars by the mid 80s switched over to VSS. Is your car TPI or is it the last year of the LG4? If it's TBI, or TPI, then it's definitely a VSS.

If it's a carbed motor, then it's an LG4 and you probably are cable driven. If this is the case, then you should have no problems. However, if you have TBI or TPI, then you do in fact have VSS and you'll have to get a kit. Summit Racing sells a kit that allows you to replace the speedo gear receiver with an electric VSS.

You might just be better off getting a 700R4. I good condition 700R4 will be superior to a Th-350 in driveability. I have a Th-350 lying around, and there's nothing really that special about it. It's a beefier transmision, yes, but it's kind of a piece of crap, and it's only a 3 speed. The 700R4 has a 4th gear.


Most Th-350s WILL come with the speedo gear assembly, but if it doesn't you can remove the tailshaft of a junkyard 700R4 and install it on your Th-350 if it has the same number of splines (depends on the Th-350 you got).