It is time to mate the NP transmission to my 235. I have checked with a couple firms who make/sell adaptors, but have not been met with any enthusiasm. Known facts are : 235 from 1958, existing rear is 1951 torque tube, trans and bell housing includes rear motor mount, NP trans is HYBRID bolt pattern--not Mopar, not Saginaw/ Muncie, but p***. side bolts match GM pattern and bearing retainers are concentric.. My evaluation so far indicates that I need to find a correct bell housing, or an adapter plate will be absolutely necessary. The mounting bolt holes on the drivers side of the NP trans back up to open air. I have a couple machine shops which could probably fab an adapter plate, but the input shaft of the NP is already 1/4" shorter than the original trans,. I would need a different shaft, but from what application? The 10 splines and throw-out bearing sleeve are compatible. Request suggestions for continued progress.
I don't know why they did that, since there is also a version that used the standard 1955-up Chevrolet bolt pattern. The only bell housing for yours fits the V8 block. Maybe if you had an adapter to bolt a Chevrolet pattern automatic to a 235, you could bolt the V8 bell to that.
You can make an adapter to extend the pilot bushing outward...then put a plate between the transmission and bellhousing. Chevy used two different size front bearing retainers, the transmission you have apparently uses the larger one that was on trucks starting in 1968.
How about welding a couple of new ears on the trans, or a piece of bar stock down the side? If there is enough meat on the NP bearing retainer, turn it down to size. If not, open up the hole in the bell housing. If you fit the bearing retainer first, you could use the bell housing as the jig for welding the new ears on.
The aftermarket makes a pilot bushing with a flange on it that sticks it out 1/4". It's for use with a block plate when using a blow proof bell housing.
I've since sold mine, but here's a pic of the bellhousing I had with my MY6. the transmission had a Mopar A833 bolt pattern, and the bellhousing had a dual pattern for GM transmission as well. Yellow circles indicate the GM holes for that side of bell.
Thanks for the feedback. I had one of these units--an MY6---20 yrs ago, and it was a direct bolt-in to my 350. The idea of welding ears to the trans is worth a try, and there is plenty of meat on the bearing retainer that I can turn it down
You could always mill flat recess in the bellhousing, to accept a piece of flat bar that would bolt to the NP mounting holes, and the bellhousing bolt holes on that side. The other side, the holes align for both Mopar and GM pattern.
The easiest adaptor is to hunt down a GM pattern NP440 / MY6 casing Or better still install a GM NWC T5 instead
I have been looking for a GM pattern unit for many months w/o success. I am considering the T5 route, but don't like the low first gear in the S10 2 wd units. My strongest wish is for OD..
If you can't weld aluminum, you could do the prep work, jig it up and pay someone to weld it. The price should be within the range of the price of an adapter.
Try the Astro/Safari van T5 and swap the shifter top. Or if you want the shifter slightly to the drivers side [aka Muncie/T10/MY6] you can shorten it by cutting and welding . It is only steel Ratios are: 1st Gear: 3.50:1 2nd Gear: 2.14:1 (approximate standard GM V6/minivan spec) 3rd Gear: 1.39:1 (approximate) 4th Gear: 1.00:1 (Direct) 5th Gear (Overdrive): 0.73:1
Can you build an adapter plate that will bolt to the bellhousing or transmission using counter sunk bolts ? With a lip machined on the bellhousing side that will go into the hole in the bellhousing and a recessed groove for the transmission to slide into . I had a friend of mine who works at a machine shop make an adapter for me . To mate a s10 T5 to a Chevy 6 bellhousing.
Could get creative and redrill the trans on the drivers side. that top bolt would be fun. Or weld an ear on the bell
The only issue with that method is the 235 bellhousing needs to be installed first ,then the flywheel and clutch installed from underneath. This would make it extremely difficult to slide the transmission in last, and install these two bolts from the inside. Even a MY6 bellhousing with a "block plate" adaptor would be difficult due to the 235 chevy having bellhousing engine mounts [but these could be welded to the block plate] The cost of all these funky adaptors and the sale of the MY6 trans could purchase a GM pattern T5
The bottom is EZ That top one would be fun But why not consider welding a tab on the top drivers side. Or use a stud instead of a bolt on the top after relocating the hole. Still would be tough tightening a nut
The bellhousing for my 292 Chevy 6. I drilled out the threaded holes in the block . Then helicoiled the holes in the bellhousing. I used socket head bolts in those 2 holes because they were close to the block . I never did get that project finished and on the road . But the engine , bellhousing and transmission are bolted together
@treegrower This ^^^ makes some sense. Use the correct MY6 bellhousing [correct depth for the trans input] And find an Adaptor used for a TH350 transmission to the 235 blue-flame block [the TH350 has the Same pattern as the MY6 bellhousing] The engine will need a 168 tooth flywheel [later 235] and a truck starter which is bellhousing mounted. The flywheel will need a spacer to allow for the thickness of the adaptor [for starter engagement] AND a pilot spacer. But this doesn't address the rear side mounts BUT there are adaptor bellhousing mounts available for TH350's into 55-57 Chevys which could work. But as usual , we throw a truckload of $$$ at something trying to justify what we already have. These adaptor kits run around $700-$800 Me personally ,would either sell the MY6 and find one that fits [or a T5] OR Sell the 235 and buy a 250 /292 six which has the same bellhousing pattern as the MY6 bell AND modern engine side mounts. A 292 six with an MY6 would outlive most of us HAMB members and the vehicle will end up having a 150lb diet because of this.
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