A bit of advice...

[TrucknAndy]

I recently purchased a 72 GMC fleetside with a donated 86 chevy engine. The issue is I am not certain out of what. It would be much easier to get engine/tranny parts if I knew what it came out of so I could search the parts first based on actual information. I think I am going to answer my own question here, but would it behoove me to pull casting #'s off the engine, tranny, and heads? I dont know how stock the engine is which is why I mentioned the heads.

I am not certain how to search for parts based on the numbers, but I figure I could provide them to a parts store, and get what I need. The reason this came up is I have a minor leak. Originally thought the culprit was the valve cover gaskets. Only after the second trip, and bringing in the old gaskets did I get the right part. But, it seems now it is tranny fluid, and its either coming from the pan, or the shift linkage on the side of the case. Would be helpful to know what type of tranny I am dealing with to search for parts.

I am no mechanical brain child, but can figure things out pretty easily. However, I am feeling somewhat gimped, and hate not having info...makes you sound like an idiot when you're looking for parts, and advice.

Thanks,
Andy

[BMERDOC]

When I bought my 67 the owner said he thought it was a 292. When I got it home and checked the block numbers and carb number I narrowed it down to a '77 passenger car 250. Imagine how I woulda looked comin back to the parts store with a bag full of parts because none of them fit. Find the numbers and figure out what you have. It really doesn't take that long and saves a lot of time. Short answer: Yeah. your right. Look it up and fugure out what you have.

You can id the block by finding the number just in front of the passenger head, the cylinder head has an id number cast into the top under the valve cover and the trans can usually be id'ed by the pan bolt pattern.

[TrucknAndy]

Thanks for the quick response. I'll definitely get the numbers, and keep them handy. I'm accustomed to going to the parts store and saying I have an X year, X make, X model with X engine, and I need X. So using the casting numbers to get parts will take some getting used to.

Unfortunately, the gentleman I bought it from said it had an upgraded cam..type unknown. That shall remain a secret until the engine gets rebuilt I suppose.

Andy

[67_C-30]

Welcome to the board!

The easiest way to check your tranny is ID it by the shape of the pan. I've posted a chart below for the most common GM RWD transmissions. Its most likely going to be a TH350 or TH400, but could be a 700R-4 if the transmission is an '86 too.

On your engine, check and see what side your dipstick is on. Also, check and see if your valve covers are perimeter bolt style or center bolt style. This will give you a general year of the engine, and you will better off geting the parts stores to look up parts for the engine, rather than your truck The parts store guys aren't going to recognize numbers - Trust me!

[67_C-30]

Forgot to mention, small block Chevy's had the dipstick on the driver's side until 1979, and on the passenger side after 1980. Below are pics of the center bolt vs perimeter bolt style valve covers. The center bolts debuted in 1986 and were used until they quit making SBC's in production vehicles. There are still new some crate engines from GM that come with perimeter style.

[TrucknAndy]

Thats great...at a glance Im thinking its the 700, or the powerglide, but Ill give it a look see tommorrow, and see what we are working with.

The tranny dipstick is on Pass. side, and the shift linkage is on the drivers side, but if I had to guess most are setup that way especially with column shifter autos.

[TrucknAndy]

Mine has perimeter bolts. Thanks again for the great info...

[67_C-30]

Originally Posted by TrucknAndy

Thats great...at a glance Im thinking its the 700, or the powerglide, but Ill give it a look see tommorrow, and see what we are working with.

The tranny dipstick is on Pass. side, and the shift linkage is on the drivers side, but if I had to guess most are setup that way especially with column shifter autos.

Yes, the trans dipstick will always be on the pass side - I was talking about the engine itself. How many gears does that trans have?

[67_C-30]

Originally Posted by TrucknAndy

Mine has perimeter bolts. Thanks again for the great info...

It is possible that it could be an '86 model, since it was the changeover year, but most were centerbolt in '86. Now it could be a '86 shortblock with older heads. I lot of things can happen as old as these trucks are. I bet when you went to get '86 model valve cover gaskets the first time, that's why they gave you the wrong ones.

[TrucknAndy]

Anything is possible. The gent asked if I had older heads stating that I would know this if head bolts were on the side of the head to which I said yes, and the first set of felpro gaskets had two double holes along one side. I assume for some sort of allignment point on a different style head...

[TrucknAndy]

Also, Im not certain what to call the truck. Seems there is no GMC C-10 of that year at least. All I have seen is C15/C1500. Im sort of getting schooled as I go, but it is fun type of schooling for sure...
I know it is a fleetside without a doubt.

Andy

[67_C-30]

Originally Posted by TrucknAndy

Also, Im not certain what to call the truck. Seems there is no GMC C-10 of that year at least. All I have seen is C15/C1500. Im sort of getting schooled as I go, but it is fun type of schooling for sure...
I know it is a fleetside without a doubt.

Andy

It would be a GMC 1500 if it is a 1/2 ton. The factory emblems and literature of that era just referred toi them as 1500, 2500, 3500.

[67_C-30]

There's no doubt that they are fun to unravel and learn all the little differences and unique stuff about every model. I've been fooling with these things a LONG time, and I still run up on oddities and new info all the time. There is a lot of collective known here (there are real guru's on this board that know 10 times what I do!) and you've come to right place to learn about your truck. You won't find a better group of guys dedicated to them.

[TrucknAndy]

I cant thank you enough for the help. Figured I would throw some pics in here as opposed to starting a new thread.

Andy

[67_C-30]

Nice truck!

You should really should start a "I'm new here, and here is my truck" type of thread though. It will get a lot more traffic, and you'll find we are all pic whores here! That way you can get the formal welcome!

[67_C-30]

BTW, is the A/C hooked up? It has the later style compressor, and that would probably required custom hoses or maybe hoses off a newer truck. Either way, its pretty cool.

[TrucknAndy]

Will do!!

[67_C-30]

By the way, I <think> I see a chrome dipstick on the driver's side -and if it is - the PO was wrong about the year of the engine...

[TrucknAndy]

No the a/c isnt hooked up because of the exact problem you mentioned. I've been holding off on dropping the dough because I was considering a Classic Auto Air setup as I dont want to throw money at a system Im not certain that works or not. I know the heat works, but being a mechanical rookie I am assuming that they use the same blower so that is all I know that works, but all the parts seem to be there. So it should just needed hoses and a charge..

[TrucknAndy]

And, there are dipsticks on both sides. If I remember correctly they are both chromed dressups. The one on the driver side is oil and the pass is tranny...

[67_C-30]

Originally Posted by TrucknAndy

And, there are dipsticks on both sides. If I remember correctly they are both chromed dressups. The one on the driver side is oil and the pass is tranny...

Ok. If it was a 1980 - up block would be on the paassenger side. That means your engine is 1979 or older.

[TrucknAndy]

I will do some casting number digging, and see if we can unravel the mystery for good...

[TrucknAndy]

Based on oil pan shape its a Turbo 350, but I'm going to find the casting numbers to confirm.

I got the block casting number tonight(3970010) which from what I have found is a much earlier block than originally thought. It may have come out of an 86 truck, but thats not where it started its life. Those numbers indicate it is a 350 4 bolt main from a corevette, camaro, chevelle, monte carlo, truck, and a few pass. vehicles, but the year range would be mid to late 60's up to 72. It could have very well been out of a truck very similar to mine originally. But, we shall never know.

Thanks,
Andy

[67_C-30]

Originally Posted by TrucknAndy

Based on oil pan shape its a Turbo 350, but I'm going to find the casting numbers to confirm.

I got the block casting number tonight(3970010) which from what I have found is a much earlier block than originally thought. It may have come out of an 86 truck, but thats not where it started its life. Those numbers indicate it is a 350 4 bolt main from a corevette, camaro, chevelle, monte carlo, truck, and a few pass. vehicles, but the year range would be mid to late 60's up to 72. It could have very well been out of a truck very similar to mine originally. But, we shall never know].

Thanks,
Andy

There's a stamped code on the pass side of the block near where the water pump bolts that will tell you what it came in. There's also a date code on the back of the block that tells the year. IIRC, the 010 blocks were produced from 1970 - 1980.

Also, contrary to a a lot of published data, all 3970010 blocks aren't 4 bolt mains. The vast majority I've seen are, but I have a 2 bolt 010 block in my shop.

[67_C-30]

The good news is that a 3970010 block is a better casting than any '86 block would be. The casting is thicker and has a higher nickel content.