348 questions

[badger56]

Hi guys I am newer to the W motor world, I bought two engines to build one for my 56 chevy. I really wanted something different for my car rather than a normal small block chevy... I love SBC's but wanted something different.

I am trying to decide which engine is a better one to build for my car. I would like help identifying what I have and which is better.

Both have the same block casting numbers 3755011 passenger car

The first engine I bought has cracked heads #3758379 (had magnafluxed) but a good block and crank, block has been cleaned and magnafluxed with no cracks, standard bore with decent ridge and heavy pitting. Pistons were really rusted in the block so the pistond and rods were junk. Intake 3770083

T030IH. I cant find the "I" I have pictures but havent figured out how to post, my files are too large

The seceond I thought (was told by owner) was a truck block but its not T827H. Have not dissassembled yet.

Here is my questions:
How much can I safely bore a stock 348? Im not building a race engine just a nice street motor.

Is there any way to determine what Cam I have? it is stamped "X" and "P"

Were the Marine blocks cast with higher nickel content like newer marine blocks?

Any information appreciated

thank you
Mike

 

[CDNpontiac409guy]

Mike,
Forget the "nickel phenomenon"... it doesn't exist.
Some of these blocks were machined with two giant valve reliefs at the tops of the cylinders. If one or both of your blocks does not have two cut-outs, use it.
.060" over is nothing to be concerned about. Even .080" is done all the time. I personally, have run one .125" over, for 12+ years, in a heavy load application.
Recommendation.... use a 409 3.5" stroke crank, 366-427 3.76" stroke BBC crank, or aftermarket 4.00" stroke crank.

OH, the "I" is actually a 1 . .... so "0301" , which would be March 1 assembly date.

 

[wally72974]

Both of your 5011 blocks are the same. You could put a 409 crank in if you want to make a nice little stroker out of you 348.
At 30 over you would have about 379 cubic inches
I would skip trying to make your heads better and find some aftermarket ones. If your going to do 3 deuces you can't use aftermarket heads.
If your building a street motor less than 5,000 rpm's then you won't have any problems with that block.
If your drag racing (more than 5,000 rpm's) then I would find a different block. 7655 would be the best 348 block for drag racing.
They were made in 64 and 65. For street use your 5011 block is just perfect.

Aubrey is correct. I forgot to tell you about the double notch block. (good call Aubrey)
Aubrey knows a lot more than I do. I'm just a part time 348/409 nut.

 

[badger56]

Both of your 5011 blocks are the same. You could put a 409 crank in if you want to make a nice little stroker out of you 348.
At 30 over you would have about 379 cubic inches
I would skip trying to make your heads better and find some aftermarket ones. If your going to do 3 deuces you can't use aftermarket heads.
If your building a street motor less than 5,000 rpm's then you won't have any problems with that block.
If your drag racing (more than 5,000 rpm's) then I would find a different block. 7655 would be the best 348 block for drag racing.
They were made in 64 and 65. For street use your 5011 block is just perfect.

Aubrey is correct. I forgot to tell you about the double notch block. (good call Aubrey)
Aubrey knows a lot more than I do. I'm just a part time 348/409 nut.

I know one of the blocks is not double nocthed, but I havent torn down the other yet.

The only reason I asked about the nickel contents was that the block I have that has been cleaned is really silver in comparison to the other engines I have done before. One of the heads from that engine is much darker than the other which matches the block.

I think I got the pictures figured out.

 

[badger56]

 

[models916]

Truck blocks will have the 4 bosses on the front drilled and tapped. 2 left, 2 right for the motor mount

 

[badger56]

Like this? It has a truck pan on it and truck waterpump/pulley. Now I will need to pull the heads and see.

They girl I bought this engine from (family friend, husband died recently) her brother in law has a 409 tripower engine as well sat next to this one, I wish I could buy that from him too.

When I bought this engine I thought if I ever need a crank or connecting rods for the other I would have it so I only paid $300 for the entire engine. I hope that was a good purchase, it turns over. They said it used oil when pulled.

were the bosses drilled for front motor mounts? Would a truck block have the same casting numbers? or would they be different?

Here is the date code on this engine.

I like this, I am already learning a lot. Thanks guys

 

[badger56]

Are the cranks internally balanced? I have a muncie 21 I would like to run behind it. So Im wondering if a small block flywheel can be used. I know the bell houseings are interchangable. I dont know if the oil pan will clear the steering on a trifive (56)

I need to learn what is interchangable with these engines. Is there any distributors that will interchange with 348's or will I need to buy new?

 

[Ronnie Russell]

Welcome, badger. If you will use the "search" feature for the 348-409 engine section, you can learn the answers to all of your questions and you will also learn a ton of information that you can use during your build. A true wealth of information. Plus, will give you plenty to do during the long winter months.

 

[oldskydog]

Both of your blocks are H code which is a turboglide 250 hp car application.

 

[62impala409]

Are the cranks internally balanced? I have a muncie 21 I would like to run behind it. So Im wondering if a small block flywheel can be used. I know the bell houseings are interchangable. I dont know if the oil pan will clear the steering on a trifive (56)

I need to learn what is interchangable with these engines. Is there any distributors that will interchange with 348's or will I need to buy new?

Do a search on which pilot bearing to use in the crankshaft flange. I believe the turbo glide cranks were machined different than the power glide cranks. We use the 168 tooth flywheels with the block mounted starters. 348/409 distributors are all you can use without an adapter. Leo

 

[Fathead Racing]

Mike,
Forget the "nickel phenomenon"... it doesn't exist.
Some of these blocks were machined with two giant valve reliefs at the tops of the cylinders. If one or both of your blocks does not have two cut-outs, use it.
.060" over is nothing to be concerned about. Even .080" is done all the time. I personally, have run one .125" over, for 12+ years, in a heavy load application.
Recommendation.... use a 409 3.5" stroke crank, 366-427 3.76" stroke BBC crank, or aftermarket 4.00" stroke crank.

OH, the "I" is actually a 1 . .... so "0301" , which would be March 1 assembly date.

In certain blocks .060" is a concern. Due to core shift some of the old blocks will not bore without problems. If I were boring to .060" over a sonic test is a cheap insurance.

 

[mailman]

Concerning the oil pan clearing the steering. ..Check to see if your oil pans are just alike. I had to notch a truck oil pan to get it to clear the steering in my 56. I have heard that some will clear, mine didn't.

 

[benchseat4speed]

Here's to puttin' a rowdy 348 (stroker!!) in a 56 chevy Looks like mailman did it too

 

[1961BelAir427]

I think the only stock pans that fit are 65 passenger pans. ??

 

[mailman]

Here's to puttin' a rowdy 348 (stroker!!) in a 56 chevy Looks like mailman did it too

Well, yeah, I did it but then I took it back out and used it in a 34 pickup truck. My ole 56 has a small block in it again for now. Who knows what the future holds though?... I have another 348 shortblock.