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1971 big block

A

ashy22

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Hi
Back in 1993 I purchased a red 1971 454 LS5 Corvette in Florida and shipped it back to the UK where I live.
I had always wanted one since I was a kid!!
During a recent restoration by me, I discovered that the blocks engine number position has a plate over it with the words
" National Engine and Parts Co " on it, together with the following: -
" Engine Code No T1659 "
" Engine Stock No 72391 "

I am guessing that this company did an engine rebuild job or replacement at some time.

Looking back through yellow pages archives, I found a company in Atlanta – Georgia

National Engine and Parts Co
820 Dekalb Ave
Atlanta
30307 2525

Looking now at this present time, it seems that this company no longer exists??
The previous owner lived in Georgia, therefore he could have had the work done here.

Do you guys know anything about this company?
Is there any way of finding out what the original block was?
I would love to know the history of it.
Any feedback would be greatly appreciated.

Cheers
Paul
 
B

Bullitt

Guest
Hi there Paul. I can't help with the company information, as I have no knowledge of it. Another place to look for a casting number, would be at the front of the passenger cylinder head. The block sticks out a bit here with a small pad with a stamped number. This should help decode the block further. Usually the area is quite dirty, so a good scrubbing should help reveal it.

--Bullitt
 

rwd

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IIRC, there are a number of 454's including truck and marine engines. There should be enough info on one of the vette websites to help with the id info on the block, head and intake and exhaust manifolds. If not, one of Antonick's books will.

It's also possible the place just changed names or has been bought by a larger rebuilder like Jasper and is doing business under another name. You might try reverse lookup.

It's likely a rebuild, but there's nothing wrong with that. Actually, the ancillaries are imo more important than the block per se. Of course, they can be changed if, for example, it's a later, lower compression variant.

If the plate's over the old number, perhaps it can be removed to expose the original. The rebuild number is unlikely to be of historical significance...

I think I might start by looking at the parts number of the manifolds, etc.
 

rwd

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No problem. Great cars. Keep us posted, and good luck.

BTW, I didn't have any luck with the rebuilder/address. If it's DeKalb NE, the address appears now to be a four family flat. There is a machine shop with a similar name in Michigan, IIRC.

Post any numbers you find, someone'll likely know or be able to help.
 
A

ashy22

Guest
Thanks again rwd

another lead I had was

National Engine and Parts Co
4216 W. Martin Luther King Drive
St Louis
MO 63113

Maybe a sister company at the time (1993)?
 

rwd

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Very likely. There's no listing for it or a similar business at that address or in the city/county area.

The thing about it is that even if you locate them and the numbers remain the same, it might not tell you what you really want to know, i.e., which 454 block with what heads, internals, externals, etc. They might just treat them generically.

I know a lot of Chevelles got blown up, and I'm sure some Vettes did, too, (although they were less favored for drag racing) and it must have been out of warranty. Consequently, it would probably be luck of the draw as far as which unit you got and whether it would have been a short block or the full unit.

I have no idea how closely they tried to match the engines. Obviously, a '71 would be a different animal from a '74, for example, and there were usually several variants each year. Certainly, earlier would generally be better. OTOH, anything that screws on will also unscrew, so it's not as if you'd be stuck with something you weren't happy with.

There are books that list the part numbers of all the Chevy components, btw.

It's fascinating stuff, though. I had a modified '70 LS5 4-speed coupe, and I still miss it.
 
A

ashy22

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Engine block number.

Further to earlier posts, I have now found the engine number stamped on the pad just forward of the passenger side cylinder head.
It is T0412TRH

According to the Corvette black book the number for a 1971 454 LS5 with auto box should start with "T" for Tonawanda engine plant and end in "CPJ" so therefore its had an engine swap.

Does this number mean anything to anybody or could you point me in the right direction?

Does the "T" in thr TRH mean its from a truck and if so is this a bad thing.

I think Sherlock Holmes would struggle with this one! :0)

Cheers
Paul
 
1

1redvet

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I found a web page when I was looking up my engine and it looks like it is a truck block but I'm not sure what year it is. Web address is www.nastyz28.com good luck
 
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It came out of a truck originally:

1973 TRH Truck 454 240 400 LS-4 VIN Z, L, 10, 20
1974 TRH Truck 454 245 400 LS-4 VIN Z, L, 10, 20
1978 TRH Truck 454 250 LF-8 VIN S, 30, fwd
1980 TRH Truck 454 225 LE-8 VIN W, 30, fwd

Check the casting date and that will narrow it down.
 
A

ashy22

Guest
Thanks for that John.
Where will I find the casting date?

So my car is not the 365hp LS5 monster that I thought it was :( or could the rebuild / replacement have been done in a way that put it back to the right standard. Is there any way for me to find out?
Cheers
Paul
 

rwd

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That could go either way. It could have been a block, a short block or an entire engine. Obviously, removing salient components from the original and reinstalling them on the new block would be more labor intensive than simply pulling the old unit and replacing it. Whether an actual unmodified truck engine would even fit under the hood or in the compartment (manifold height, etc.) remains to be seen.

The only way to find out how much is original is to check the individual part numbers stamped on the intake manifold, heads, exhaust manifolds, etc. and see what they're off of.

3993820 is the head
7041204 or 05 is the carb, depending on trans
1112051 distributor
1100543 alternator

Those are the only relevant numbers for an original that I have, although I've seen books with all of them. Similarly, there might be a website or a GM parts site that would be helpful for cross id'ing. I don't want to guess at locations, but the numbers aren't usually obscured.

The engine's performance is the sum of the parts, and there's no way to tell without checking each one individually. Of course, while some of what you learn may be unpleasant, anything that's been done can be either undone and even improved upon. Good luck.

...and http://www.71corvette.com/index.html
 
A

ashy22

Guest
More clues

I removed the passenger side rocker cover and found the following cylinder head casting numbers

J/8/74
GM9T
336781

which according to my black book means that I have got a 1974 cylinder head on a 1973 or 1974 big block truck motor, as the block suffix is TRH.

What would I have to do to get the horsepower output to the same level as the LS5 unit that was originally in there? Is there much difference anyway?

Any thoughts guys?

Cheers
Paul
 

rwd

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My reference shows 336781 as the head for a '74 vette 454, which was then rated at 270hp (the '72-74's were rated at 270 and 275hp). I don't know at this point if it's the same p/n as the truck head. BTW, if you haven't adjusted valve lash, do so, if it's excessive, the valves aren't opening all the way.

As you likely know, IIRC, in the early '70's, GM switched from a gross to net hp rating and cut the compression. Much of the difference in hp is the switch in rating systems. There is little consistency in the heads, carbs, etc. from year to year.

I'm not sure how much different the truck engine or block itself would be, if at all, and apart from racing applications, the key components would be the pistons and cam. The intake manifold and carb are the obvious targets for replacement if they're truck parts, but they may not be. I really think their part numbers are needed to find out what you really have first, though. The intake manifold p/n should be in the casting. Checking parts sources would reveal whether the truck and car internals were the same or not.

The undercar exhaust system is quite inefficient and unless you have headers and/or sidepipes, that would be an easy target.

If you haven't check this site yet, it has some info you can use:

http://www.nastyz28.com/bbcmenu.html
 
A

ashy22

Guest
Block casting number

Further to recent posts on decoding my 1971 big block.

I removed the plate (see attached photo) to reveal the block casting number 3999289 with date D 10 73

The Q-jet carb was stamped 7041200

The inlet manifold has a casting number of3855287 dated A29/70

Having searched and read as many Chevy block/engine sites as I can find, it seems that the truck block that I have could well be a heavy duty unit. I suppose the only way to tell is to take the sump off and check the number of cap bolts.

Thanks for all your input
Cheers
Paul
 

rwd

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The carb's of a '71 Camaro, El Camino or Chevelle, and there's a 3955287 iron oval port head intended for a Rochester Q-jet 4V around that vintage.

As far as id'ing the block, it may have other identifying characteristics. Check big block hotrodding books (which often explain the variants) or experiment with searches. I pulled the carb usage off a search. The truth is out there. Good luck.
 

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