I am adding one (maybe two if I am lucky) factory slant to v8 trans adapters with all bolts and crank spacer to my collection of slant goodies and have dreams of replacing the factory style overdrive "4 speed" in my 69 D100 with a 5 speed.

Will it bolt up with the adapter and what year trans/bell should I look for, will it need any machine work? I'm not worried about floor or cross member mods just the initial bolting together of the parts.

Engine is a solid lifter 225 with the usual hop up goodies. 268 cam, ported head/intake and headers, 60 over, headers, offy 4bbl, motorcraft 2150 carb, hei, GM alt, 3.91 rear.
It runs awesome, is my year round daily driver and will roll down the freeway all day long at 70 but it just wants one more gear to be really happy. Besides the fact that I can't leave anything alone for too long....

Is it an AX-15 or an NP535/NV-2500?

I think the NP-535 can bolt in using the NP-435 bellhousing allowing for the use of the HD 11" slant six/base big block clutches, and not needing the adaptor. (Of course you will need a flywheel from the truck that you get the bellhousing from, preferrably the late 70's-80's trucks as the 60's trucks used the direct drive starter as well and you'd have to switch/ go backwards in starter choices, the later trucks used the stock starter, so that would allow you to retain a mini-starter as an option.

I don't think anyone has done the AX-15 conversion, here a couple of concerns would come up in my mind:
1) The Ax-15 bellhousing will have to be compared to an LA-727 tranny since the adaptor plate were made for that tranny if the bell is more like the 904 then the adaptor plate will need some modifications and a mock up of the assembly will need to occur to see what needs to be fitted and ground....

2) The other item would be the fly wheel...you will need a late flywheel for an LA engine (318,5.2/3.9L for neutral balance) as it is a bit larger than the stock A-833/3 speed slant six flywheel...as previously posted one of the flywheel bolt holes will not line up with one of the crank bolt holes so you will be egging the hole or welding and redrilling to make it a 100% fit.

Both of those trannies will have closer ratios in 1-4, but 5th gear is still OD like the A-833OD so the rpm isn't going to change in 5th gear at highway speeds compared to what you have now...

A-833OD ratios 1-OD: 3.09,1.67,1.00,0.73 (depends on year and gear pitches)
Ax-15 1-5: 3.83(really granny with 3.91 rear), 2.33,1.44,1.00,0.79
NV2500/NP535 1-5: 3.79,2.29,1.48,1,0.79
NV3500 is similar to NV2500, but the close ratio version has a 3.49 1st gear instead of the 4.02 1st.

What would get where you need to go is a Tremec 6 speed that has 6th as the "double OD", so the last gear is closer to 0.55-0.6 for OD instead of 0.73 to lower your highway cruise rpm as desired...prices on the T-56 and similar boxes are still out of reach (you can buy a really nice Dodge Dart for the cost of a tranny)...

The T-5 bell mod would be a little better option if you can find a T-5 that has the 0.63 5th gear ratio (SVO/ V8 mustang box=$500+) to bring the highway rpm down a hair.


2 cents,

-D.Idiot

Current trans is a a833od with 3.91's and a motorcraft 2150 carb. Gas mileage is pretty awesome for the cam.

We do have a BW T5 out of a firebird sitting in the shop that my buddy was going to put in his 48 chevy behind a built 261 before he went another direction. It has been rebuilt and has the mechanical speedo. I know it isn't the ideal T5 and the shifter is set pretty far back but with the 64 T-bird buckets I'm going with that won't be an issue.
I might play around with that one on of my mock up slants. I have a few different bellhousings laying around so it shouldn't be too hard to make it all fit...

I have a Ford T-5 behind my slant. It is out of a 4 cyl. Mustang, and has a rather high 5th gear (high numerical ratio). To compensate for this I put a low ratio rear in. It turns 2000 rpm at 65 mph. I charted all this out before assembling anything. I do not like the granny first gear, but with the low rear, it is not too terrible. I chose this tranny because the input shaft is longer than the v-8 version, or the GM one. This allowed the use of an adapter plate on a standard slant bell.

Keisler makes a kit, but it is expensive. McCloud has talked about a modular bell system to mount any tranny behind any engine. You might ask them about this. Maybe it was just talk.

Good luck on your project.

Sam

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I looked at doing this once. IIRC you will have to cut a huge chunk out of your firewall to drop the Dakota in.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I am not sure if you are referencing my set up, but I did not cut the firewall. I DID cut the floor. In fact I cut the cross member and fabbed a new one. I would think a truck has more room.

Sam

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I sold some 440's to guy that was doing a 440 Dakota. I looked at the old 5 speed and think it would have required cutting the firewall. That what he thought. www.bigblockdakota.com GregZ good guy.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I also have a slant six to V8 727 adapter from an A-100 van.
I'd also like to know if this could be used for a five or six speed
swap.