78 chevy

[Captain Ruggy]

Hi everyone, I just acquired a 1978 chevy pickup. It's got a six inch lift on it and what I was told is a 400sb. Is there any easy way to verify that it is a 400? It has aftermarket valve covers and air cleaner.

It also has 6 lug axles so is it safe to assume that it is a 1/2 ton truck?

It also has a TH350 tranny, not sure of the t case.

Overall a very strong running truck, I traded a 1998 chevy malibu for it. The malibu had 230,000 miles on it and we never drove it anymore, so I figure we got a decent trade.

Thanks for any help.

[RidinDirty78]

Hey sounds like a good deal i have a 78 too it was free haha nothing in life is free. but as for the engine find the casting numbers on the front of the block and look online and you can find a web sight that will give you the numbers. for the axles yes if they are 6 lug they are a 1/2 ton axle. if you clean off the t-case you should find a plate on the t-case that will tell you what kind of transfer case you have.

[jenks21]

The harmonic balacer is an indicator as it is different from the 350's and 305's.

Casting number on the back of the block near transmission mount. Suffix code on head deck on the passenger side in the front.

later
jenks

[indytrucks]

Originally Posted by Captain Ruggy

Is there any easy way to verify that it is a 400? It has aftermarket valve covers and air cleaner.

Casting numbers on the block. While your add it, get them off the head too if you can.

It also has 6 lug axles so is it safe to assume that it is a 1/2 ton truck?

Should be. Pics and what is a k1500, 2500? Should be a 44 or a 10 bolt front. Could be either as this was a transition year. And the rear should be a 12 Bolt.

It also has a TH350 tranny, not sure of the t case.

Should be a chain NP203.

Now that I gave you some info, go search the boards man. All that info is EVERYWHERE on here. And all that is going on the fact that its still a stock 1/2 or 3/4 ton truck. The PO could have changed any of that.

[Captain Ruggy]

Thanks for the info, I know all about PO's but this truck isn't too bad. It has some small stuff that needs taken care of but it runs great. The choke is messed up and the PO has it wired open, so I am going to see what's going on there. I may just put in a manual choke if I need to.

The axles are stock. It had a six inch lift put on it just within the last couple months. Before that it was stock.

I will check out the numbers. Thanks again for the help.

[hilborn283]

if the harmonic balancer has a big fat notch in it along the diameter,it's a 400.also it will have three frost plugs per side.

[67JOE]

dont 400 have 2 freeze plugs down each side, instead of 3

[Joesgarage]

Originally Posted by 67JOE

dont 400 have 2 freeze plugs down each side, instead of 3

All small blocks have two frezze plugs, BUT the 400. Three

[Captain Ruggy]

Ok guys, I will check for the numbers and the freeze plugs.

Overall, I am pretty happy with this truck, it runs great once it warms up. I do have one more question though. What is the shift pattern on the t case? The original knob is missing and I am not quite sure about the pattern. Thanks.

[indytrucks]

the pattern should be

(front)
4L
2L
N
2H
4H
(back

Dude, do you know how to use the e-web?

[Captain Ruggy]

Originally Posted by indytrucks

the pattern should be

(front)
4L
2L
N
2H
4H
(back

Dude, do you know how to use the e-web?

Sure I do, but why if the answers are so readily available here? I came to the Chevy forum because I have Chevy specific questions. So are you telling me that this is not the place to find answers to my questions? If I wanted to hear crap from just anyone I would search the web. I figured the Chevy guys would know. But you are right and this should be in the general 4x4 forum.

Anyways, thanks for the answer and your pattern makes sense.

[Wheel28]

Just for clarification not all 400's came with three freeze plugs. the casting number 3951511 was 4-bolt main three freeze plus Early 70-73 car and late seventies truck. Casting number 3951509 was 2-bolt main 2 freeze plugs 73-76 car and late seventies trucks.



Will

[jenks21]

3 my ass.

Here is my 400 casting number 3030817




Like I said the balancer could be an indicator, because 400's were externally ballanced, that is why there is the chunk missing, unless you have an externally ballanced 350 or 305.

Get the numbers off of it plain and simple it will be the tell all without the confusion of how many freeze plugs some dumb ass tells you it will have.

later
jenks

[Joesgarage]

What I should have said
"All 400 Small Blocks have Provisions for three soft plugs"