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Block ID Help

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xissix

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Jul 22, 2006
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Location
Idaho
Hi everybody, I'm a long time reader of ck5, but this is my first post! :o I have usually been able to find what I am looking for and have found this site to be the best for chevy truck info, but I found something I haven't been able to get an answer for (maybe my search skills aren't up to par).

I recently bought a 1980 3/4 ton K20 for $500. Going to pull the axles and other misc parts off of to put on my 1973 blazer. Little back ground on the blazer: Picked it up 2 years ago for $100 from the second owner with only ~22k miles on it! (I couldn't believe it, figured it had turned over, but everything on this truck is like brand new, just aged from 20+ years of sitting in the sun) :D Brakes on the blazer went bad in 1983, sat since in the guys driveway until he died and his son sold it in an estate sale to me. Truck sat so long on the asphalt driveway that the wheels (tires where toast years ago) where in 3 inch deep divots.

Anyway, on to my very long way of asking a question :o. The 1980 K20 I picked up ran and drove, so I figured it was a good deal. On the way home stretched it's legs and it runs awesome! Well when I got it home the engine was knocking (to much stretching I guess). Sounds exactly like a rod knock, so I haven't driven it since. Bummer, deal, but figured nothing to it since it was an 80. Well I noticed the heads have no accesory holes, so I did some digging and got the following info off the block:
Casting Number: 3932388
Stamp Number: T1104HN
Dial on the back points to about 4 o'clock

From what I can decode from these items and other posts, this is a 1965-1969, 327-350, 250hp-375hp. But that is all I can tell. How can I figure out the year/application with out tearing it down? Wouldn't normally matter to me as I have a couple other 4 bolt 350's in the garage, but from the "HN" at the end there, this could be a 375 horse 327 Corvette FI motor. If so, may be able to help fund a locker for my 14BFF :D
 
'65 was the only year that Suffix was used for FI apparently, but the casting number shows up as only being used for 1969.

I used Nastyz28.com for decoding data, so that's only as accurate as their site. :)
 
1965 HN 327 t/ign., m/t 375 FI Vette
1968 HN 327 Pwrglide, reg gas - 4 full size/Chevy II
1969 HN 327 tur 350 - - full size
1969 HN 350 tur hydramatic 300 4 full size
 
Get a pic of the block specifally the area around the oil filter. Does it use a spin on filter or a cartridge filter? I can rule out if it is a chevy II block or not. If it is a chevy II block they go for some big dollars as they are very rare to find as they were a small journal engine 62-67 but used a spin on oil filter and the block has a different shape around the oil filter area. The last i looked the bare block was going for 1000.00 alone.
 
Suffix code is only part of the equation.

3932388 was NOT used any earlier than '69, therefore it's not a Corvette FI block from '65.

Which means it's from a full size car.
 
Ah, I see how it works now. So nothing too special then, just a 69 327/350. That's good and bad I guess. Well, on to tearing this baby apart!

Thanks everyone!
 
4X4HIGH said:
Get a pic of the block specifally the area around the oil filter. Does it use a spin on filter or a cartridge filter? I can rule out if it is a chevy II block or not. If it is a chevy II block they go for some big dollars as they are very rare to find as they were a small journal engine 62-67 but used a spin on oil filter and the block has a different shape around the oil filter area. The last i looked the bare block was going for 1000.00 alone.
Click to expand...

I just checked it and it has the standard screw on filter and a standard looking truck pan, probably nothing rare it seems since it's a 69.
 
I decided to tear off the heads, the block is .030 over.
Now brings another question. The engine in my blazer has only 24K original miles on it now, (little marvel mystery in each spark plug hole and a tune up on the blazer motor, after 20+ years sitting she started right up and runs good execpt for the smoke). but smokes on startup and decel so I want to give her the once over gasket and seal wise and some upgrades (cam, intake, headers) Not sure if I should freshen up my low mile original 350, or do a full rebuild on this 350 with the knock (above upgrades plus RHS 180 heads). Needs a crank (.020 under already), and pistons and such, but once it's done it's all fresh and built (but expensive). The stocker would be cheaper, but not new pieces and less power...
 
Or build the .030" over block while you continue to drive the "old one".
 
Rering was were I was leaning. I drove the blazer for the past couple years while I collected up all the parts for my build, but I toasted the transfer case chain in the 203 last summer, so it's not driveable right now. Wonder if that 69 block is worth much?
 
Nothing special about the block. The whole engine is only worth 150.00 max as a rebuildable core BUT it's already a .030" bore so you'd be lucky to get 100.00 for the complete engine. Keep in mind that's here, where you live could be a different matter.
 
I'm curious to see what the cylinder walls in that 24K mile block look like . Smoking a little could be a couple things , but I would love to believe those cylinder walls and journals are gorgeous :)
 
After sitting for 20+ years the rings are no doubt froozen in the ring lands of the pistons. Sometimes after driving they will free themselves but most of the time it will require new pistons and rings.
 
The 24k engine runs pretty good, has 160-170 compression on all cylinders. Figured the smoke was intake seals as it only does it on decel and startup after sitting for a bit. I was hoping to just put some umbrella seals on the valves, run a quick hone on the cylinders, re-ring/re-bearing it, new cam/lifters and go, measuring everything first of course :)


Forgot to add, oil psi is 30 when hot at idle and up to a hair over the 45 at 3K rpm.
 
xissix said:
The 24k engine runs pretty good, has 160-170 compression on all cylinders. Figured the smoke was intake seals as it only does it on decel and startup after sitting for a bit. I was hoping to just put some umbrella seals on the valves, run a quick hone on the cylinders, re-ring/re-bearing it, new cam/lifters and go, measuring everything first of course :)


Forgot to add, oil psi is 30 when hot at idle and up to a hair over the 45 at 3K rpm.
Click to expand...

That was my thought when you said it smoke a bit.
If there was a problem with the rings, you wouldn't get good compression so you just proved it.:D
 
imiceman44 said:
That was my thought when you said it smoke a bit.
If there was a problem with the rings, you wouldn't get good compression so you just proved it.:D
Click to expand...

Got news for you, bad rings will make the engine smoke (all the time) but it will still have good compression. Now i see that it only smokes upon start up and decel which is usually seals or guides.
 
So just from observing I should be on the good side of the fence then. :). It doesn't smoke when cruising or when I give it gas, just on the before mentioned times. If rings are stuck, a set of pistons is no worry, be a good reason to upgrade to hyp flattops. I'm going to shelf the stock heads for future projects and put on a set of the RHS 180cc runner heads with a comp xtreme 4x4 254 cam. With an edelbrock intake/avs carb and some hooker ceramic thick wall headers, dual 2 1/4 exhaust, should be a nice upgrade from stock :)
 
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