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1970 SBC 350 Transmission Questions

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First post!  Before the witch-hunt begins, I've become quite adept with the search function here.  I bought a JTR-converted '75 280z with an SBC 350 out of a 1970 Chevrolet Bel Air about two years ago.  Searching on this website has helped immensely in getting this thing up-and-running, and fixing the bungles the previous owner made.

 

My Z initially had a TH350 automatic transmission which, while nice in a drag, was not sufficient for highway driving.  And I'm not planning on doing any racing.  So it's currently on my garage floor, where it belongs.

 

I've been looking at manual transmission options, and it seems the best route is to look at other cars that had the 5.7L V8...such as Corvettes and Trans-Am's.

 

I'm thinking about getting a flywheel, clutch kit, and T56 transmission from a '93-02 Trans Am. 

 

I'd like to hear any advice from folks who went this route.  My biggest worry is, given the age of my engine (i.e. it is internally balanced and has the two-piece rear main seal, rather than the one-piece) the newer '93-02 parts won't match up. 

 

Any wisdom / advice? 

 

Thanks all!  Happy motoring!

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I have used 1990 Camaro World Class T5 transmissions  in two 240Z  SBC 350 builds. Both cars were built as daily drivers (son's college car, my work car).

 

The five speed is highly appreciated on freeways and road trips.

 

The T5 is tilted towards the driver's side, but poses no problem for installation. Use the Camaro bell housing so that the rear trans mount is horizontal. Only a small amount of trimming is required on the left side of the trans hump where the shift tower comes up through the floor.  I have pictures if you need them.

Edited by Miles

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What size flywheel and clutch did you use?  My understanding is that the T-5 bellhousing will not accept a 14" diameter 168 tooth flywheel, which is what I had and would be getting with the T56.  I guess the price difference between the T5 and T56 would make up for the cost of a new starter.

 

I've done a lot of research on the T-5 and actually purchased one (though I didn't do ENOUGH research...the one I got was from a V6 and had the Ford bolt pattern.)  Given that they were only behind 5.0L V8's, were there any issues mating up the flywheel and clutch with the 350?

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0.875 Clutch Master Cylinder : used both of these……

 

http://www.summitracing.com/parts/wil-260-10374

 

http://www.summitracing.com/parts/til-75-875

 

 

Camero clutch slave Napa  NCF 73110

 

Clutch kit

http://www.summitracing.com/parts/ZZZ-HP1675-1A

 

Flywheel

http://www.summitracing.com/parts/ZZZ-50-6516

 

Clutch slave hose adaptor

http://www.summitracing.com/parts/RUS-640281

 

 

Hitachi Gear Reduction Starter

Hitachi starter gear reduction PSL100

Edited by Miles

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I actually looked at that as an option.  I've still got a V6 T-5 with the ford bolt pattern. 

 

How did you account for the tilt?  I assume one could fabricate a custom crossmember?

 

Also, I noticed that on the V6 T-5's the tailshaft housing is longer.  When I test-fitted my V6 T-5, the shifter location ended up about 4" behind (towards the back of the car) the hole.  Did you have to account for this somehow?

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I actually looked at that as an option.  I've still got a V6 T-5 with the ford bolt pattern. use the T5 for a V8

 

How did you account for the tilt?  I assume one could fabricate a custom crossmember? If you use a Camaro bell housing there is no need to make a custom crossmember as the rear trans mount will be horizontal. As mentioned above you will need to trim the trans tunnel on the driver's side where the shift tower comes up.

 

Also, I noticed that on the V6 T-5's the tailshaft housing is longer.  When I test-fitted my V6 T-5, the shifter location ended up about 4" behind (towards the back of the car) the hole.  Did you have to account for this somehow? Forget the V6 T5  you have. It won't work.

 

I recommend that you buy the Jags that run 240Z V8 conversion manual as it answers all of your issues in detail.

 

Search the drivetrain section for T5 installs.

post-178-0-27316100-1460575577_thumb.jpg

post-178-0-56879600-1460575597_thumb.jpg

post-178-0-97401400-1460575607_thumb.jpg

Edited by Miles

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I am sorry to contradict you Miles, but I am currently daily driving my sbc v8 240z on a v6 t5 out of a 96 camaro.  This is from my experience adapting this transmission to work with an early small block chevy.  The same could be done with a ford mustang t5, but you need a 10 spline clutch, different front bearing retainer and a different pilot bearing.. maybe more, but I did not personally perform that conversion, so I dont know anything for sure about it.  Just that the same principle will apply.  Measure and math it out.   

 

Anyway, to answer your questions (maybe), this is the only pic I have on me at work.

 

Crossmember before bracket fab

 

This is where my transmission mount ended up, I welded a tab straight off the back of the crossmember under the bushing and then gusseted the edges for strength(imagine an upside down U shape box of steel) and then drilled 3 holes in it for the bolts.  Also, to match the angle of the trans in the back(since the shifter sticks straight up with the jeep bellhousing) I heated and bent the driver side of the mount downward a little and turned a 1.40" spacer(if i recall correctly, I will measure and take more pictures when I get off work) on the passenger side to slant the crossmember with the bushing.

 

As for shifter location, mine actually seemed a touch too far forward.  I am not sure what bellhousing you are using to test the distance, but with the Jeep one, it is pretty close to the dash. 

 

And if you have a th350 in there with a long tailshaft, as i did, you should be able to use the same 27 spline driveshaft you had previously. also of note is that if we are talking about the same t5 it should have a 26 spline input shaft and an internal slave cylinder, it came off of the 3.8 v6 camaro in 1996 era.

 

Like I said, I can get you some more pics later today.

 

edit: I should again add, while using the stock crossmember works, a custom one would be better because the clearance from the bolt head to that side is really tight and is a pain to tighten them, you could probably beat it in a little first or cut it out and reweld a step into it, but at that point, you are about done with a custom job.  I just did what I knew I could do to get it running and out playing quickly.  You may want better for your future ;)

Edited by ahbeyra

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That is amazing. Too much work for me though.

 

It was nearly too much work for me, I could not agree with you more, Miles.  I went through two different master cylinder options first, a Tilton and a different jeep model, two different ways of bending the hard lines to get to the slave, 2 different front bearing retainers... lots of pull apart and measures in between.  But, that is the main reason I made an account here, to share that knowledge gained through much pain and mental frustration.  Like I said, you could find posts all over the internet talking about how "all you have to do is get a jeep bell housing and slap some Camaro junk in it, and boom, instant conversion!" but no one had seemed to ever actually do it, all just speculation and brother's daddy's uncle's best friend's mailmen that had gotten it to work.  Or part numbers that don't exist.  It is just hard to resist using such an undesirable transmission.  those T5s meant for Chevy V8s are so rare, and when people are selling one, they think they have a TKO or something... its crazy, at least here in Georgia, cheapest I ever found one is 600 bucks.  I mean, yeah, its not THAT expensive... but, the V6 T5s are almost literally a dime a dozen.  Anyway, I hope to see more broke budget minded people able to enjoy this 5 speed conversion.

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I am not sure about where they might be sold retail wise, all I know is the v6 ones like i used are available for less than $100 often around me.  We have a lot of pull-a-parts around Atlanta that flat rate any transmission:

 

TRANSMISSION - AUTO W/CONVERTER $74.95 $25.00 TRANSMISSION - MANUAL $74.95 $25.00

 

Off of their website at http://www.pullapart.com/parts/pricing/ the 25 being a core charge.  Most of all, no one but other 95-2002 V6 Camaro owners want those 5 speeds.  So they are almost always still in the car.  Just give it a quick once over, checking that it spins when it should and not when it shouldn't.  Check fluid for chunkies and flakes... I mean, its a $100 dollar transmission, soooo, it may not be perfect... but I can buy a whole lot of them for the price of one equally weak(but better geared) v8 trans out of earlier Camaros.

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It was nearly too much work for me, I could not agree with you more, Miles.  I went through two different master cylinder options first, a Tilton and a different jeep model, two different ways of bending the hard lines to get to the slave, 2 different front bearing retainers... lots of pull apart and measures in between.  But, that is the main reason I made an account here, to share that knowledge gained through much pain and mental frustration.  Like I said, you could find posts all over the internet talking about how "all you have to do is get a jeep bell housing and slap some Camaro junk in it, and boom, instant conversion!" but no one had seemed to ever actually do it, all just speculation and brother's daddy's uncle's best friend's mailmen that had gotten it to work.  Or part numbers that don't exist.  It is just hard to resist using such an undesirable transmission.  those T5s meant for Chevy V8s are so rare, and when people are selling one, they think they have a TKO or something... its crazy, at least here in Georgia, cheapest I ever found one is 600 bucks.  I mean, yeah, its not THAT expensive... but, the V6 T5s are almost literally a dime a dozen.  Anyway, I hope to see more broke budget minded people able to enjoy this 5 speed conversion.

 

I got super lucky.  Found a T-5 from an '86 V-8 Camaro...complete with clutch and friction disk in pretty good condition, as well as flywheel (will need resurfacing, but that's cheap) all for $350.  It's not World Class, but I figure at that price if I manage to destroy it, it won't be such a loss.

 

But yeah, most of the V-8 T-5's I was seeing were upwards of $700

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Thanks miles! Is there a reason to use this starter vs the iroc camaro manual trans starter?

 

 

 

I prefer gear reduction starters because.........................

 

Advantages of gear reduction starters:

  • lighter
  • high torque
  • compact
  • new not rebuilt
  • My local speed shop has them
  • My experience with stock starters has  been that when heat soaked they become weak making it difficult to start a hot engine. Never had a heat soak issue with a gear reduction starter.

post-178-0-98859200-1487965185_thumb.jpg

Edited by Miles

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For a good source of Chevy engine and transmission information go here:   https://www.thirdgen.org/

 

Thanks for sharing all the info that you share on this!

 

I've got the t5 mocked up. Next is my driveshaft stuff.. Mine came with a 700r4 that someone had cobbled together. The rear of the driveshaft that connects to the rear end was hacked together and fit very lose.  Is there a place you would recommend for having a driveshaft made at? And is there a specific flange I should be using that will mount to my r180 rear diff correctly?

 

Thanks!!

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Just pick a reliable local driveshaft shop to modify/balance the driveshaft. You will have to learn how to measure for the correct driveshaft length. Also, driveshaft angle (phasing) is very important.

 

If you don't know about driveshaft balance and phasing your car will vibrate going down the road. Search HybridZ and google.

 

JTR sells the the Chevy driveshaft to Datsun differential flange adapter you need.  Or do a HybridZ search for the part number.

 

Buy the JTR 240Z V8  swap manual and read it several times. Most of the answers to your questions are there.

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Just pick a reliable local driveshaft shop to modify/balance the driveshaft. You will have to learn how to measure for the correct driveshaft length. Also, driveshaft angle (phasing) is very important.

 

If you don't know about driveshaft balance and phasing your car will vibrate going down the road. Search HybridZ and google.

 

JTR sells the the Chevy driveshaft to Datsun differential flange adapter you need.  Or do a HybridZ search for the part number.

 

Buy the JTR 240Z V8  swap manual and read it several times. Most of the answers to your questions are there.

 

It's on my list of things to pick up. I seen JTR's flange after I posted that, I guess I had over looked it.. Thanks!

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Bought the JTR book and the TPI/TBI book as well.

 

Does everyone just run a bolt thru the floorboard and through the JTR trans mount? Is that strong enough to hold, given the gauge of the facotry sheet metal? Has anyone used another steel plate inside the car for added strength?

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Posted (edited)

73z85.0

 

You bought the JTR, but did you read it?

 

See page 8-2 of the JTR  Datsun Z V8 Conversion Manual.  Everything you need to know about this install is in the manual.  

Edited by Miles

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