new guy with a few questions

[binderbart]

Hello everyone, I'm new to this site. I just acquired a few chevy's in the past few weeks and thinking of doing a build:
1st truck is a 1978 4wd half ton: it had a 350 that runs, 400 turbo auto, NP 205 transfer case, body is shot. no locking hubs.
2nd truck is a 1984 gmc 3/4 ton 2wd, 350 that runs, 350 turbo auto, body is really nice for iowa.
3rd truck is a 1985 gmc 1/2 ton, 454 big block(the oldest boy claimed that) four speed manuel tranny, not sure on the transfer case, body is shot, has manuel lock outs with 308 geared axles. body is toast
Here's the questions, My plan is to drop the good body (84)on the 78 4wd frame, will it bolt up the same? I'm using the four speed out of the 85 with the hydralic clutch. I know i'll have some issues with the tunnel cover, that doesnt bother me, and will the 205 case work behind the manuel tranny? the frame on the 78 is nice as it has sat since 96. Will the manuel locking hubs be an issue when I switch the axles from the 85 to the 78? will something have to be changed in the transfer case? I dont have a lot of money in all three of these so I could be a nice truck for cheap. We pulled the 350 out of the 78 and some of the block numbers don't make sense either. heres what was on the back of the drivers side block-39700, no idea what this is, I have seen 3970010 on some of my 350 blocks but never this code, also where the suffix code should be there was only this-31472???. usually there are more numbers here and part of the VIN. any help would be great. thank you in advance.

 

[89Suburban]

Great entrance, welcome aboard.

 

[binderbart]

Great entrance, welcome aboard.

LOL...I was actually trying to think of something clever to open with and thats all I could come up with. I was a die hard chevy gmc guy years ago and then I slipped off into the I.H. world. I do own the only vehicle my dad ever bought new, a 1979 GMC 3/4 ton. Its out at a buddies place, time to restore it. I"ve been driving a 95 jeep cherokee as a everyday driver and the best I can get is 14mph, figured I might as well be back in a truck. I did a build similiar to this years ago, some sweet deals just fell into my lap and I thought I'd throw a truck together real quick. Just can't seem to remember what fits what.

 

[89Suburban]

Got any pics?

 

[binderbart]

Got any pics?

not right now but I will have the camera at the shop this weekend, he wants to pull the big block and i got a scout body to swap. I'll shoot some and post them up.

 

[HotRodPC]

Lotso Questions crammed together there. I guess I'll take a stab at answerwing some in no paticular order.

The 3970010 is a common 350 2pc Rear Main block, also used as large journal 327 in 68 and 69 and is the most common, available in both 2 and 4 bolt main. Chances are the block you see is the 3970010. Sometimes during casting, the #'s can fall off the mold. I've got a set of heads that happens to be missing a # too. I'll try to post the pics if I can find them

Yes, you can put the 84 body on the 78 frame. The mounts are different in the 73-80 trucks, and the the 81-87(91) trucks. So you have to use IIRC, the body mounts for the FRAME, so you'd use the 78 body mounts, not the 84 body mounts. Someone correct me if I'm backwards on that. But you get my point. It's one way or the other, but fairly certain it's use the correct mounts for the frame. Also the front frame horns are different in the 73-80 and the 81-87, so you'll need to use the front bumper off the 78. I'm wondeing why not put the 84 Body on the 85 Frame since that body is toast too??? And you mentioned axle swap from the 85 to the 78. Obviously you're trying to consolidte the good 2wd body on a 4x4 frame.Yes, you will have to cut and weld in the trans tunnel for the Tcase into the 2wd Cab.

The NP205 can be mated to the SM465 4 speed, but you'll have to get the right adapter. It also matters with output shaft of the SM465 you have. There are different ones, so if you don't have the correct SM465 output shaft, then NO it will not work with out opening up the transmission and swapping shafts. In an 85, the Tcase is probably the Alumumin Case NP208 married to that SM465. Being the NP205 is from a Turbo400, you might be in luck as far as splines, I'd have to check to make sure, but the adapter for sure will NOT be correct.

EDIT: I'm adding on here, putting 2 and 2 together, on this 78, are you sure that's not an NP203 Full Time Tcase? That would explain why you don't have Manual Lock Out Hubs. I have a feeling it's a full time 4wd. Check into that and make sure.

 

[binderbart]

Lotso Questions crammed together there. I guess I'll take a stab at answerwing some in no paticular order.

The 3970010 is a common 350 2pc Rear Main block, also used as large journal 327 in 68 and 69 and is the most common, available in both 2 and 4 bolt main. Chances are the block you see is the 3970010. Sometimes during casting, the #'s can fall off the mold. I've got a set of heads that happens to be missing a # too. I'll try to post the pics if I can find them

Yes, you can put the 84 body on the 78 frame. The mounts are different in the 73-80 trucks, and the the 81-87(91) trucks. So you have to use IIRC, the body mounts for the FRAME, so you'd use the 78 body mounts, not the 84 body mounts. Someone correct me if I'm backwards on that. But you get my point. It's one way or the other, but fairly certain it's use the correct mounts for the frame. Also the front frame horns are different in the 73-80 and the 81-87, so you'll need to use the front bumper off the 78. I'm wondeing why not put the 84 Body on the 85 Frame since that body is toast too??? And you mentioned axle swap from the 85 to the 78. Obviously you're trying to consolidte the good 2wd body on a 4x4 frame.Yes, you will have to cut and weld in the trans tunnel for the Tcase into the 2wd Cab.

The NP205 can be mated to the SM465 4 speed, but you'll have to get the right adapter. It also matters with output shaft of the SM465 you have. There are different ones, so if you don't have the correct SM465 output shaft, then NO it will not work with out opening up the transmission and swapping shafts. In an 85, the Tcase is probably the Alumumin Case NP208 married to that SM465. Being the NP205 is from a Turbo400, you might be in luck as far as splines, I'd have to check to make sure, but the adapter for sure will NOT be correct.

EDIT: I'm adding on here, putting 2 and 2 together, on this 78, are you sure that's not an NP203 Full Time Tcase? That would explain why you don't have Manual Lock Out Hubs. I have a feeling it's a full time 4wd. Check into that and make sure.

thank you for the answers. The 85 frame is rusted badly, the 78 was my old truck I sold to a guy, 2 years later the tranny went out and it has sat ever since (since 1996) at his parents farm. That frame only has minimun surface rust and the plan is to coat it with OSPHO and then chassis saver. Now, by body mounts are you referring to the bushings or the whole steel mount itsself? The way I understood you was I would have to cut the body mounts off and reweld them in the right place? Transfer case is a 205 in the 78 from what I can tell, I might just run the 208, haven't heard much bad about them. I just know the 205 is gear to gear and no chain, I like that option, and if I go with the 208 it would be a good match to the front axle with the lock outs. Years ago I put a 85 2wd cab on a 86 4wd, I thinking now I did weld in the cover for the t-case lever. I ended up trading that truck for the mint condition scout II I now have, kinda slipped off into the scout world for the past 12-15 years and I kinda miss the ol truck so I thought I would build another, I got lucky and in the last 3 weeks I ended up with 3 of them for a song.

 

[HotRodPC]

NO, you shouldn't have to cut off any body mounts and reweld them. Use the same ones but the mounts have different size openings and this is why you'd need to use the bushings for frame to mount the newer body. So NO, no hacking needed to do it.

They NP208 is not a bad unit. But you're right, the NP205 is considered bullet proof due to being gear to gear. NP208 does also have the advantage of being lighter, and a much better 4 Lo Crawl ratio at 2.61:1 where the NP205 doesn't even double the ratio, falling just short at 1.96:1. So basically, you're taking all 3 trucks to make 1 truck. Lots of work, but it can be worth it in the long run. Sounds like you have some good powertrain parts to decide from.

 

[binderbart]

NO, you shouldn't have to cut off any body mounts and reweld them. Use the same ones but the mounts have different size openings and this is why you'd need to use the bushings for frame to mount the newer body. So NO, no hacking needed to do it.

They NP208 is not a bad unit. But you're right, the NP205 is considered bullet proof due to being gear to gear. NP208 does also have the advantage of being lighter, and a much better 4 Lo Crawl ratio at 2.61:1 where the NP205 doesn't even double the ratio, falling just short at 1.96:1. So basically, you're taking all 3 trucks to make 1 truck. Lots of work, but it can be worth it in the long run. Sounds like you have some good powertrain parts to decide from.

First off let me say you have a cool avatar,Watched that with the grandkids a few times. What was Mater, I always thought he resembled a 56 I.H. truck. But thats probably because I have one (body anyway) that I'm planning on building a ratrod out of down the road.
On the body mounts, thats good news for me, I might just go ahead and buy new ones, why not, for all that work it would be the time to pop the new ones in, Energy suspension should have them.
Transfer case I'm leaning more towards the 205 now. I looked up under the 85 today and it does have a 208, what scares me is how low that W shaped crossmember sits. The crawl ratio isn't a big concern. The scouts I run have a dana 20 with a 2:1 low and I get along fine with that. Isnt first gear of the 465 running 6:72 to 1? with that and low range I should be fine I would think. One of the boys buddies told me today he had a 205 out of a 85 chevy that had a manuel tranny, probably do some swapping with him. I did take a second look at that 85 and the frame is scary. And I went and looked at the 78, I'm amazed at how good of shape it is in. It has a nice front and rear chrome bumper too. Another issue too is, the 85 has a big block that was swapped in place of the 305 that was in it. The front leaf springs look like their tired.
Well, I guess this weekend I'll have to shoot some pictures of all three so I can post them in here. Thanks for all the help so far, amazing how much a guy forgets in 15-20 years.

 

[HotRodPC]

yeah, I liked the Cars movie. I watched it with my son, and being a Tow Truck driver.....

So it does sound like you've got a good plan. That'll be 1 torquey set up. 454/SM465/NP205. Should be pretty stout too and hold up. Yes, the SM465 has a Granny 6.XX first gear so you're good to go there. Just a matter of getting the right adapter and output shaft on the SM465. I also don't see a big need for a very deep crawl ratio for what I do. 1:96 or 2:1 would be good enough for me.

The front leafs will look tired. It's original that they're negative arched. 2 in lift springs are just a tad positive and 4in lift are slightly positive, and 6in lift are very positive.

 

[binderbart]

not quite, the oldest son and I bought the 85 half and half, he wanted the 454 and I wanted the rest, I'm going to run the 350, I'm sure it will do what I need. A truck I built years ago was the same set up, I ended up trading it for the scout II I have now, the scout is nice and a first place trophy winner, I enjoy it every summer when I get it out, I just miss my truck. I'm also in the middle of another scout project right now too, a frame off beater......don't ask! I might have to put that on the back burner till I can get the truck on the road.

 

[HotRodPC]

not quite, the oldest son and I bought the 85 half and half, he wanted the 454 and I wanted the rest, I'm going to run the 350, I'm sure it will do what I need. A truck I built years ago was the same set up, I ended up trading it for the scout II I have now, the scout is nice and a first place trophy winner, I enjoy it every summer when I get it out, I just miss my truck. I'm also in the middle of another scout project right now too, a frame off beater......don't ask! I might have to put that on the back burner till I can get the truck on the road.

Sure it will. I've got the option for a 454 that I have in a C20 for one of my 4x4's but I don't think I'm doing it. I'd rather work over a 350. Unless you're entering truck pulls, IMO, 4x4's are more about gearing and traction than they are motors. I've seen a couple V6 and I6 trucks go places the 454's couldn't make it. It all came down to gearing and the right traction. Granted, some lockers and tires the 454 likely could have made it, but point is, 4x4 isn't as much about the motor as it is the traction. I'd rather spend the funds on axles, tires and suspension that I would the motor.

 

[binderbart]

couldn't agree more, the scout I use for the trails I ran with just a open diff. big change when I welded the rear axle and switched to super swampers, night and day difference. I had a cherokee that I ran with a detroit in the rear and 456 gears. It had a set of 32x9.5x15 TSL's on it and it seemed to easy when offroading. I'm am amazed at what is available for a small block. and pricing is right too. and now I have 3 -350's to work with, life is good some times.

 

[HotRodPC]

couldn't agree more, the scout I use for the trails I ran with just a open diff. big change when I welded the rear axle and switched to super swampers, night and day difference. I had a cherokee that I ran with a detroit in the rear and 456 gears. It had a set of 32x9.5x15 TSL's on it and it seemed to easy when offroading. I'm am amazed at what is available for a small block. and pricing is right too. and now I have 3 -350's to work with, life is good some times.

There you go. Work over a 350 then. I have all total 4 350's, 2 of them are runners, and 2 are builders, and the 454 is a runner too. The shame is, I use the 1/2 ton 4x4 with the 350 to the grunt work, not the 3/4 with the 454. Moreso cuz the 454 truck has 3.21 gears, and the 4x4 350 half ton has 3.73 gears and it doesn't seem to work near as hard as the 454. I'm sure it's gear ratio more than anything though. But I do like getting in the 454 and going for a ride to my dads 70 miles away at 80mph and you don't even hear the motor. In the K1500, it's wound up pretty good at 70.

 

[binderbart]

did some searching, lots of neat stuff in here. I also found a section for projects. So I'll probably start a build tech in there. Someone might find some useful info some day. I'll take lots of pictures and share the joy/grief along the way. One thing I was looking for and couldn't find, I'm thinking the locking hubs out of the 85 front axle should work in place of the full times in the 78 axles, that would save me a lot or work and I could pull the 308;s out of the 85 and keep them as spares. This weekend we're going to do a lot of prep work for this build. should be interesting.