changing transmisions out what do i need?

[WayFast84]

I have a 400 sbc with a th350 attached to it, and I would like to use my 700r4 with it, what do I need to take the th350 off the 400sbc and then put my 700r4 and stock stall on it?

thanks
Matt

[Batman]

Should bolt right on. You may need to use the flexpalte for the 700R4 but since your car is an 84 it has a 2 piece rear main so it should all be OK. It's been so long since I've owrked on the old stuff but I think all the pre-85 stuff was exactly the same bolt patter wise as long as it was chevy stuff.

[V]

the 400sbc should require a ext balanced flywheel. most likely the 400sbc/th350 flywheel is a 165tooth flywheel. i believe youll need a 153T one for the 700r4, BUT that will also have to be ext balanced since your 305 one is neutral balance.

[WayFast84]

Damn, the cheapest one i found was like 300 bucks, plus it says i need to upgrade clutches.

[V]

oops, haha, i meant to say flexplate, not flywheel. there should be a ext balanced flexplate for a 700r4 available at a reasonable price. lemme go look now...

the 400/th350 flexplate MAY work IF a 168 tooth flexplate will clear the case/bellhousing of the 700r4. i know a 168t will not fit in an f body T5/t56 bellhousing. but since gm used the 700r4s on other vehicles, it may be bigger to clear a 168. If it does clear the housing, then you need to see if the convertor bolt pattern(3 bolts) will match up with the 700r4 convertor. If not, then you need to get a new flexplate with External balanced and the proper TQ convertor bolt pattern. 168t versions are available for under 50 bucks or so, but you need to research if a 168t will fit in the 84 700r4.

[johnjzjz]

the attachment bolt holes are the issue -- you need to keep both the front pulley and the flexplate together as they are weighted for a 400 SBC motor -- i do believe the converter will bolt up to your 400 the only thing you will need to check mixing parts like this is -- ( with the converter in place and the thans bolted up to motor you need at least .75 to .100 thousands travel ) back and forth on the converter with the two pieces bolted together -- if the converter cant be pulled back and forth when bolted together don't do it something is wrong -- hope you get what i an saying -- and the holes for converter to flexplate need to match up as well --- jz

[Tru2Chevy]

I used the stock 168 tooth 400 flexplate when I bolted my 400 up to my 700R4. Everything cleared just fine.

- Justin

[NJSPEEDER]

the factory 400sbc flexplates are dual pattern for the TC, so you should be able to jsut bolt up the stock 700r4 stuff to it and go

[WayFast84]

AWSOME! my head aches, about using the th350 are gone Thanks alot tim and justin, Do i need gaskets or anything like that??

[NJSPEEDER]

nope, just get those bolts snugged in good and you wil be ready to rock.

[98tadriver]

if it was putting a T56 in , ive done that 4 times already, i have some experience and could help.

[84HOtransam]

you will need some parts to install the trans into your third gen... a different driveshaft and crossmember

[Tru2Chevy]

Originally Posted by 84HOtransam

you will need some parts to install the trans into your third gen... a different driveshaft and crossmember

I think you mis-read....he's got a 700R4 in there now, but he didn't think that it would directly bolt up to a 400sbc.

- Justin

[84HOtransam]

Originally Posted by Tru2Chevy

I think you mis-read....he's got a 700R4 in there now, but he didn't think that it would directly bolt up to a 400sbc.

- Justin

yep i thought it was 700r4 to th350..thanks