d300 to sm420

[crusier72]

I decided that I wanted to put a d300 under my 72 cruiser. I want a flat belly because my cruiser is basically stock and isn't going sprung over.
I got the d300 in and I'm now working on
installing it and have the tcase bolted to the novac adapter with the toy flanges I made and had welded, thanks Matt.
Now on to the drive shafts I need a u joint that will operate at about 25 degrees and the 3sp ones are looking like they aren't going to do it I'm thinking of getting a mini truck shaft and using those because they have a decent operating angle.

Update I couldn't get the angles to work because the angles were so extreme. I put a 85 Mini axle under it with a cv shaft to get the pinion up a bit and for now just a welded rear.

[Isotel]

Nice. i love my D300! and the Flat Belly!

Im running a toyota CV out of a minitruck in the rear of my Cruiser, but without a spring over, you should be fine with a standard cruiser Shaft..

[crusier72]

If I was running a centered rear you are right. I still have the stock axle. I plan on going to a centered rear but for now I'm trying to get this to work.

Update I didn't get it to work.

[bustanutley]

Are you running the stock motor? If you are did you have to modify the passenger side rear motor mount for front drive shaft clearance? I have a similar project coming up and it looks like that motor mount may be in the way.

[Mbrantley]

Mark,
now that you have the D-300 in, were there alot of clearence issues, Or should I ask if the gas tank is still inplace?

You are now one step closer to destroying your front axle

Matt

[Isotel]

I would drop in a Mini truck Rear axle.. the 55" wide versions can be had for less than $100, and should work ok for now, or build a Hybrid axle, pretty easy to do

[crusier72]

I will go the mini truck rout but for now I have to get it going with the cruiser rear. I'm running a 2F.
The tcase is clocked down to the second hole on the adapter and the front shaft looks like it will just clear the passenger side motor mount and with a mini slip on the tcase end to get around the sm420 reverse bump.

[bustanutley]

in its current position how far down does the d300 hang below the frame?

[crusier72]

The d300 is abovethe frame by about an 1/2" however the sm420 is about 1/4"ish below at the rear where the drain is. I am going to grind most of that off and hope it doesn't leak to bad out the drain. Pics to follow...

[crusier72]

I got the cover fitted around the 300 tonight and the tank shimmed up about half an inch and now all I need to do is seal the hole off. I'm thinking of using a heat shield of some sort because there isn't much room between the two and I'd like to keep the tank and interior cool. I gently bent the flange on the tank up a little for clearance.
The drive shaft is just going to fit good thing I ordered the 2" od tube, I'm going to need it for clearance. That is a mini slip to get past the hump on the sm420.

[bustanutley]

thanks for posting those pictures

[crusier72]

The cruiser axle is out and I put a 85 mini truck axle in the rear to fix the drive shaft problems. I used a cv shaft from a mini in the rear to get the pinion up and out the the rocks. I welded the mini carrier with a bunch of wire and hope it holds together.

[Mbrantley]

It looks great, thanks for documenting what you did in this swap now
I wanna see pics of some front drive donuts complete with a cloud of snow arround the Cruzer (You could subsitute snow for tire smoke).

Did you actually get to drive it on the street? I am wondering how much quiter it is with the D300 now....

Matt

[crusier72]

I got the front D shaft in today.It fits like it was designed to be like that. I used 2"O.D. X1/4" DOM and machined the slip end from a mini shaft down to slide into the tube and the ujoint end I used the 3sp end and opened the id up a little to fit it over the shaft and welded it all up. it's 41 3/8" at rest so I used about 26~tube. I will get some pics when my computer starts talking to my phone again. Progress has slowed to a crawl because school started last week.

[crusier72]

Hers is the clearance and how I made the shaft. The front shaft doesn't move much where the shaft is near the motor mount it's about a foot from the tcase and two feet from the diff and this is with stock front springs that are sagged so the front axle moves up about 2" and I suspect the shaft wont get very close. I don't think a stock shaft or larger would clear if you can hit you're bump stops in there stock form.

[bustanutley]

Any Chance you can give me a dimension from the bottom of the tranny mount on the Novak adapter to the bottom of the frame rails? I’m trying to determine whether I will be able to use a standard GM tranny mount with the adapter and maintain a flat belly.

This is the mount

[crusier72]

If you mount the skid to the bottom of the frame it should fit, if you tuck the skid up between the rails it looks like it might need a little more or drive train lift. My biggest problem with the skid is the sm420 hangs below the frame, I'm going to try and grind a bit off the bottom towards the back where the drain is.
The only problem with that mount is if mount to the skid it needs to have some support, because if it's just mounted to a unsupported flat span the skid will force the tcase up when you land on a rock or hammer over a ledge possibly leading to failure of the adapter.

[bustanutley]

The plan is to use a piece of channel where the mount is and to have the mount basically inside it. Everyone else’s I have seen just use a piece of box with spring bushing on the ends. My frame isn’t welded together and I haven’t built an engine cage yet so I still get quite a bit of frame twist in the front end, the spring bushing option just doesn’t seem like a good idea, too rigid.

[crusier72]

Got it really running a couple weeks ago. I put eldorado calipers on the rear with ebrake provisions to make it past out wonderful inspections here in ma, they work ok hold it parking but not on a real incline good enough with it in gear. They stop great running sky's brackets and you're typical rotors and soft lines.
For the skid i'm running a piece of 1/2" Al and am going to put a layer of HDPE on the bottom to help the many rock encounters that i will have.
The other improvement is the front lock right. Nothing interesting there other than I used marlins seals to hopefully keep the goo separated thanks Matt.
I got it out last weekend and it works great really happy with all the improvements it's doesn't hang nearly as much in the middle and with the front locker really goes. The other thing I had to do to get the belly flat was rais the motor an 1/2" in the front and 3/8" in the rear.