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SS3964Rings
I love my Chevy Chevette!
Posts: 6
Joined: 05/13
Posted: 05/29/13 05:59 PM

OK, guys here it goes. I am new to the classic muscle car world and this game is no joke. My congrats to you skilled folk. I just got a hold of a 1969 Malibu Chevelle with a 396 engine. Nice car, ran well but the engine had a knocking sound and I decided to have it removed and checked out. All went well until the shop found that the bores were a bit grooved and needed to be cut. The problem is that the pistons have 4 rings instead of 3. The shop said the motor is probably a cheap  Mad truck motor and not a car 396 motor. I don't see how any 396 motor is cheap but whatever.If I get the bores cut where can I find these 4 ring pistons or can I have installed 3 ring pistons instead? ConfusedAny help what so ever will be highly appreciated Wink ,Thank you.  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 05/29/13 07:02 PM

why not stop here..

get the casting numbers off the block..  off the heads... off the intake.. off the crank..  unless its been machined off.. there are 2 rows of stamped in numbers on the front of the right cylinder head deck..  post those numbers..

   and usually there will be casting numbers up inside the pistons that will help some of use with piston catalogs identify exactly what pistons you have..

can you also measure the diameter of the piston.. and attempt to get a compression height measurement on the piston.. measure from the top of the pin bore to the top of the piston less any dome..    then measure the pin bore and add half that to the compression height measurement.

4 ring pistons are usually in TALL DECK big block chevy motors..   366 cubic inch and truck 427 cubic inch..  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 05/29/13 07:05 PM

.  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 05/29/13 10:56 PM

+1 Wayne
I believe it's the 10.2" tall deck truck block 366 or 427.,. 3 ring pistons are available for these blocks.
The good thing about these engines are;
4 bolt mains, forged crank and stronger than stock rods.
I'd rebuild the engine since the intake manifold and distributor will only fit the truck block and not the 9.8" passenger block.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 05/30/13 06:00 AM

+2 Wayne.

I had this happen a while back, a customer brought me what was supposed to be a 396 and it was the 366.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 05/30/13 06:22 AM

I hope this guy has the 427.

I hate it when unsuspecting buyers get snookered buy unscrupulous sellers.  
68scott385 68scott385 68scott385

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 05/30/13 04:09 PM

Icon Quotetuffnuff:
+1 Wayne
I believe it's the 10.2" tall deck truck block 366 or 427.,. 3 ring pistons are available for these blocks.
The good thing about these engines are;
4 bolt mains, forged crank and stronger than stock rods.
I'd rebuild the engine since the intake manifold and distributor will only fit the truck block and not the 9.8" passenger block.

Smile


If that is the tall deck 10.2 truck block you can make a killer 496 out of it if you are willing to change the rotating assembly.
There are kits out there to do this with and you can buy the whole setup completely balanced and ready to put together.
My last 632 was a 10.2 tall deck Dart block. It had extra clearance for the big  stroke but I still had to do some grinding.
Tuff is right about the intake but there are after market 10.2 intakes out there along with taller distributors. One of my blocks was a 10.6 Keith Black and that had to have a sheet metal intake made for it. I had a fabricator build an aluminum spacer for it and then mounted a sheet metal 9.8 intake on it.  
[[SUPPORT AMERICAN CARS, STOMP A RICE CAR TODAY.]]

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SS3964Rings
I love my Chevy Chevette!
Posts: 6
Joined: 05/13
Posted: 05/30/13 04:39 PM

Wow!sounds like you guys know your engines Wink Thank you all. I will begin by recording all the information on the block. I will then return to this forum with the info to find out what I have and where to take it from there.I will be back soon and keep you all posted. Thanks again. I feel so much better now that I found this forum and this group. Peace.  Grin  

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SS3964Rings
I love my Chevy Chevette!
Posts: 6
Joined: 05/13
Posted: 05/31/13 04:52 PM

OK, I am back. After a heated discussion with the old man who sold me the car, I found out that the engine is a truck engine but came out of a boat before being installed in the car. He offered to have the bores cut for and the 4 rings pistons replaced at his cost.As far as what type of engine(366/427 still remains a mystery due to the fact that this motor,for what ever reason has no numbers,just the word truck and a large letter E on it.I am a bit concerned being that I already had the car redone completely with sand blasting,new paint job, new rims and tires,interior and purchase all new SS396 emblems as well as a rebuild on the transmission.All I want is a good looking fast running reliable USA Musle car, not a Muscle looking car but with a wimpy heart. Peace.  

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zman123
Everything in my driveway’s a Chevy
Posts: 537
Joined: 06/08
Posted: 05/31/13 06:00 PM

Casting numbers on the right rear of the block on top of where the bellhousing bolts and below the distributor hole. post that number.  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 05/31/13 10:07 PM

366

The 366 Big block V-8 (6.0 L) gasoline engine was used only in Chevrolet Medium duty trucks and in school buses. It had a bore of 3.935" and a stroke of 3.760". This engine was made from the 1960s until the mid-1990s. The 366 used 4 compression rings on the pistons as it was designed from the very beginning as a truck engine. The 366 was only produced as a tall deck engine with a 0.400" taller deck than the 396, 402, & 454 short deck big blocks.


Commercial applications

Mark IV engines saw extensive application in Chevrolet and GMC medium duty trucks, as well as in Blue Bird Corporation All American and TC/2000 transit buses (the latter up until 1995, using a purpose-built, carbureted 427). In addition to the 427, a 366-cubic inch (6.0 liter) version was produced for the commercial market. Both the 366 and 427 commercial versions were built with a raised deck, four bolt main bearing cap cylinder to accommodate an extra oil control ring on the pistons. Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks.

427

the 427 cubic inch (426.7cuin)(7.0 L)  tall deck truck version  The bore was increased to 4.25 inches (108 mm),


so.. are the pistons just shy of 4 inches.. or 4 and a quarter inches..  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 06/01/13 08:03 AM

If you have the 427 version you are well on your way to a performance motor. Like Wayne says just measure the bore to tell.
If the seller is willing to buy you new pistons you will need to know what size rods are in that motor if you are going to re use them. Keep compression down to around 10-1 as current gas is pretty poor.
The heads on the truck motor are complete junk, they are known as peanut port heads, and you will need to change them.
A good set of Dart 320s either cast iron or aluminum will work wonders. Done right you will have a very strong performance car that will make most newer so called performance cars look sick.  
[[SUPPORT AMERICAN CARS, STOMP A RICE CAR TODAY.]]

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 06/01/13 08:24 AM

Stock length for BB rods is 6.135".,. truck rods are also 6.135" and beefier on the big end than passenger rods.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 06/01/13 07:58 PM

Yap a 427 Tall Block. Get ride of it, it's only trouble down the road. Really all parts are expensive and then will take a Dyno to see were an problems will came up.

Bob  

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SS3964Rings
I love my Chevy Chevette!
Posts: 6
Joined: 05/13
Posted: 06/07/13 04:29 PM

OK, after a bad car accident, I am back and still kicking. Here's what I found. My 396 engine is not only, Not a car engine from 1969, but a truck engine from 1968.To add vinegar to the wound, it is a 366 engine(casting # 364779)! I look up 366 engines for 68 trucks and nothing but negative comments show op. Also there is another # I found on the engine, T0125AAX, if anyone knows what this # is for, please do educate me.Is this engine really that bad? So far all has been cleaned up, the bores are cut at 40 over but still no 4 ring piston heads to be found. What are my alternatives, if any, utilizing this same engine. Had I had money to play I would just install another engine. Unfortunately I don't! So you experts or vets out there, tell me what can I do with what I have.Piston heads have these numbers on the inside, 3856253 and on the opposite side 8067, on the top of the heads, these # appear Z-12-M-14 37. Peace.  

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