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This is the story of my transfer case. 

I have a B&M 700R4 transmission. This transmission was built for a street/strip race car. It has a 2300 rpm stall, shift kit and has only 2600 miles on it. 

When I purchased the H1 from Joe he had a turbo 400 and 454 BBC with a NP205 transfer case. This NP205 is a rare one in that it was mated to a turbo 400. It has the input shaft that everyone wants. But it want mate to a 700 R4, wrong splines. The 400 has 32 splines and the 700 R4 has 27. 

I just so happened to have a old 78 GMC 3/4 ton Blazer. It has a Dana 44 up front and 12 bolt out back, 350 sbc, turbo 350 with a NP205. This NP205 is the perfect match for the 700 R4. Just get the adapter and off we go. NOT  It seems that GM made two kinds of 700 R4's.


This is the 2wd version.

This is the 4wd version. Note the length of the tail shaft. About 5 inches shorter.

This is the picture of my 700 R4. The splines only go 4.5 inches. The sleeve will have to be cut off. www.transmissionpartsusa.com sells an adapter for the 700 R4, (7q-35a). It is actually for a 700 R4 to turbo 350 conversion. It will work the other way if you have the 4wd trans. You may have to cut off about .125 inche of the tail shaft to make everything work right. 

To make this work on a 2wd trans I have to cut off 2 inches of the tail shaft and the sleeve. I have to make a custom adapter that is 5 inches long. 

This is the 7q-35a adapter. It needs to be 5 inches long instead of 1.875 inches. Our office has a machine shop that makes parts for the oil field and pipeline utility market. After hours, with the help of a machinist, I'll be making the adapter I need.

Here is the 7 inch piece of 4130 steel that is being faced.

Got it faced and now boring it out to 3 inches. The outside diameter of the smaller outset is 4.75 +-.001

Here you can see the purchased adapter in the back ground and the new adapter. This side is finished and as far as we got on Friday. The plan is to Monday finish the job. The outside diameter of the new adapter will be 6.5 inches. I left the inside diameter 3 inches so that I could cut it down on the outside. I'm planning to use studs on the trans and bolt the trans to the adapter. Then use bolts to hold the adapter to the transfer case adapter. I hope that this will eliminate any deflecting. I may weld a 3/8 inch flat plate to the bottom of the adapter and run it to the bottom of the transfer case adapter and bolt it to the bottom on the cross member. This should help in support and deflection.

Here you can see the adapter that I made. It worked great. I have to modify the tail shaft by cutting off about 2 inches. Other than that it fit perfect.


Stay tune.

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