83 GMC van engine trans ? 1 ton

[NewKid]

does anyone know or can tell us what all this means? the rpo code is MX1 for the trans, all it says is auto trans provisioned. it looks like a th400 with bolt on yoke and 2 piece driveline, metal plate on the trans says FM -21759. other is LT9 for the RPO code, is this a truck 350 engine or passenger engine and is it a 4 bolt? some engine rebuild companys say that it could be a 2 or 4 bolt. engine casting # is 14010207. The vin says M for the engine. also RPO code says-GQ1 standard ratio- this is not a full floating axle I don't think, no extention. it is a 14 bolt 9.5 ring gear, it has M3 as a casting and CZR 060g on the axle I think it is a 3.73:1 non posi. if any of this can be answered it would appreciated. Thank you

[badone07]

Can't help with the factory codes. However, you can check here for the engine code stamp to narrow it down, http://www.nastyz28.com/spmenu.html . The block could be 2 or 4 bolt and obviously you won't know positively unless you drop the pan. Being it's a 1 ton vehicle I would expect it to be a 4 bolt. The trans you can easily identify by the pan, http://www.nastyz28.com/transid.html . Bolt on yoke is most likely a 400th. Have one in my garage I pulled from a 1 ton van.

[NewKid]

to badone07: I am trying not trying to pick on just you but you were the only one that said anything about my question. I just can't imagine why GMC would have one casting number for two different applications. especially an engine. every thing has a casting number and if it were used for two diferent applications it would seem a bit confusing. So why the heck and what the heck were they thinking. Your answer still didn't address the question of whether or not this is a truck or passenger engine.

[Captkaos]

You can look up your casting number here: http://www.nastyz28.com/sbchevy/sblock.html#casting

You can look up your RPO code here: http://www.nastyz28.com/rpomenu.html OR here: http://www.73-87.com/7387info/7387traneng.htm


No clue on the axle numbers, BUT you answered your own question if it is a 14bolt 9.5" rearend. It isn't full floating. Standard axle ratio was typically 4.11, but....

[badone07]

Originally Posted by NewKid

to badone07: I am trying not trying to pick on just you but you were the only one that said anything about my question. I just can't imagine why GMC would have one casting number for two different applications. especially an engine. every thing has a casting number and if it were used for two diferent applications it would seem a bit confusing. So why the heck and what the heck were they thinking. Your answer still didn't address the question of whether or not this is a truck or passenger engine.

I haven't personally researched or have hands on with casting of blocks. However, probably the main caps were/are fitted to the block after the block was cast. Then drilled and tapped for either 2 bolt or 4 bolt mains. Therefore, the only difference would be the main caps themselves. The block would be whatever they had on hand. Then the necessary machining.

As far as whether it is a truck or passenger block, hard to say unless you look up the engine code stamp to narrow it down. If the block was ever decked, it's probably gone though. In the past trucks, vettes and full size vehicles received 4 bolt main 350 blocks. However, not always the case. The motor itself might not be original to that van. Probably has 462624 heads on it, if original to the block. Those would concern me more. I also wouldn't get too hung up on whether it's a 2 bolt or 4 bolt main either. Other manufacturers get by fine with only 2 bolt mains. Same goes for the crank as whether it's cast or forged. Unless it will be making big power, won't be a problem. "L" or "M" vin is 350 4 barrel V8, for your year.

http://www.chuckschevytruckpages.com/73-87specs.html

http://www.chuckschevytruckpages.com...s_1973-87.html

[NewKid]

thanks for the info badone07, I finally pulled the alternator back and found the numbers. they are V0224USM and Td4516172 which is the last part of the vin #. it is the original engine and has a 4 bolt main block. this is listed as truck. next question. Does this mean that it has a higher deck height? Oh, also another web site I looked at said that for this block it has #14079267 or #376445 as heads for this application. Now the next mistery, looking at the front of the van the dipstick is on the left hand side. the specs that I find are for the dipstick on the right. It looks to me that the passenger side dip stick was used up to 1979. Not on this block #14010207. I don't know what to make of it. Unless it was made for a motorhome. Again with the vin ID of M and RPO of LT9, this was also used to identify motorhome engines. which have a three more possible heads because of the smog control sometimes using 2 pumps. however, this uses only one pump that flow through the exhaust manifolds. Still, the main question would be about the deck height. I was reading somewhere else that talked about three distinct blocks that were most commonly used for the high performance engines and they are Block ID numbers - 10066036, 14010207, 14016379
Head ID numbers - 462624, 14071114, 14079261, 14094093, 10147898. So either way it would be hopeful to have what you said for a head. Thanks agin John Sage

[badone07]

No problem. The deck height should be around 9.025" like any other factory sbc. The "tall deck" blocks were limited to BBC, 366 & 427 from the factory. Measuring approximately 10.2".

The dip stick reference you made is actually reversed. 80 and up on passenger side. Below, driver's side.

Probably the block casting used the most for performance builds would be the 1969-1980 3970010 or "010" as referred to. Same casting used to make 350's, 327's and 302's. That's regardless whether they are 2 bolt or 4 bolt mains. The 14010207 block you have to look for cracking in the lifter valley. The 10066036 is a Mexican manufactured crate motor. I have one in a 78 Suburban I'll be taking out soon, which replaced a 14016379 block.

Head wise, the 462624 are common to find on the trucks. They are supposed to flow and are later versions of the older 882 castings. Problem is the various valve sizes that were used and they are lightweight, crack prone POS. I would actually hope you didn't have them, unless you are needing an all matching vehicle. 14071114's and 376445's are a possibility because the years they were used. However, if your heads are original, they won't be any of the other castings you listed because of years used. What are the plans for the motor or van?

[NewKid]

hey you sound like a nice person. what do you think of katrina?Ive been up since 3:30 this morning watching this storm. My poor girlfriend. First thing first. I had a heart attack a year ago feburary, then broke my right foot in March, then had another heart attack in May of the same year. I am getting a disability check because I can't work as a cook any more and I'm to old to be retrained, 51 . go figure . Anyway I've learned to take the first step then the next and so on literally. I broke the foot in 3 places and pushed the bones to the right. In order to know what to do with the motor and tranny I have or get something all together different is the purpose of this discussion. It pays to be careful. Even if I have a hard time doing that. My girlfiend owns that 84 s-10 4x4 durango that is in this forum and she has put a new windshield and back window in this rig as well a brand new interior and will be painting it some day. At the present time I am just checking because the Van has some rust and need to know whether or not it is worth fixing up. And no it doesn't need matching numbers It's all good to know what is what. I would like some zip though. I have a mig welder and torches as well as the other shop tools to remove the engine and tranny and what ever else. This has the rochester 4 barrel carburator. I was planning to get aroung 300 HP out of this and maybe more. The transmission will definately handle it with a rebuild. I have nothing but time. Oh, I live in an area that doesn't require emisiion testing, what a break. thanks again John

[NewKid]

post another. you are right about the head. just took off valve cover and found 462624. Does this I would be better off looking for another setup. Thanks John