Visual differences between 427/390hp and L-88?

[jdads2]

I have seen a 427 in pics and very briefly in person and I have never seen an L-88. What would be the most outstanding difference between the 2 powerplants?

Thanks for answering this stupid question, but if you don't ask, you never learn!

Dave

 

[Tom Bryant]

Hi Dave,

The big things are the hood which is taller and actually houses the air cleaner element inside the opening above the carb. The carb has an air cleaner base that seals to the hood when it is closed. There is a small diameter cover and screen over the carb. It is a single Holley 4 bbl on a high rise aluminum manifold and of course the heads are aluminum.

There are many other differences but these are the big things you would see first.

Tom

 

[Stallion]

So, if you don't have a taller hood, then you can't put in a bigger block? Would that be a limitation? Thanks.

 

[Tom Bryant]

Yes. The small blocks had the smooth hoods except the LT1 that needed more clearance for the high rise intake. It used a standard big block hood which is taller for the extra height the big block requires. Then the L88 needed even more room, height wise, so it got an even taller hood.

Tom

 

[Stallion]

Hmm...so I guess you/I have to be choosey in the Vette and body depending on if you/I would want to in the future put in a big block.

But, say the Vette has a taller hood and it, at the moment, contains a big block engine. And then you want to put in a smaller block. Would it be possible? Could you put a smaller block in a taller hood Vette? Would it fit properly?

What, in all, would you need to consider when putting in a new and/or different engine in a Vette as a replacement for the current one? I guess there must be some guidelines that the new block to put in must follow according to the Vette and it's body/frame specs?

 

[JohnZ]

Any C2/C3 Corvette will accept any Chevy small-block or big-block, as they were built that way originally, and all the parts are available to install either engine. The key issue is intake manifold and carburetor height - the taller intake/carburetor combinations require unique hoods. C2 small-blocks all used a flat hood, big-blocks used a raised hood, and the twenty '67 L-88's used the production big-block hood outer panel with a special inner panel with a rear air intake and plenum housing that sealed to the foam ring on the exposed air cleaner base, and the air cleaner element was mounted to the hood.

C3 small-blocks all used a flat hood (except the '70-'72 LT-1, which used a raised big-block hood), big-blocks used a raised hood, and the '68-'69 L-88's used an even higher raised hood.

 

[jdads2]

OK, then on the original question: the l-88 would have the single carb and a cowl induction hood with a true cowl induction air cleaner and gasket. The 427/390 hp would have an air cleaner and cover but would need the cowl induction hood for clearence more than functioning with the air cleaner.

 

[JohnZ]

Correct - the 427/390 has a normal air cleaner on a Q-Jet with a low-rise aluminum manifold on 68's and 69's (and on a Holley on a low-rise cast iron manifold on 66's and 67's). Opening the hood on an L-88, you'll see a shiny black air cleaner base with a foam seal around the outside, and a circular wire screen at the top of the carburetor; the hood inner panel becomes the air cleaner housing when it's closed. L-88's have a high-rise aluminum manifold with a BIG Holley 4-barrel, and '67 L-88's have a huge black road draft tube from the driver's side valve cover that runs down past the frame.

 

[jdads2]

Thanks.

I am going to be looking at a vette that a guy bought with his house. All he knows is that it is a "68 or something like that and has a big block 427 in it". He just wants it out of there so he can start storing some stuff for yhe house.

 

[Tom Bryant]

Keep us posted on what you find. Might be a real bargain lurking there.

Tom

 

[Stallion]

Any C2/C3 Corvette will accept any Chevy small-block or big-block, as they were built that way originally, and all the parts are available to install either engine. The key issue is intake manifold and carburetor height - the taller intake/carburetor combinations require unique hoods. C2 small-blocks all used a flat hood, big-blocks used a raised hood, and the twenty '67 L-88's used the production big-block hood outer panel with a special inner panel with a rear air intake and plenum housing that sealed to the foam ring on the exposed air cleaner base, and the air cleaner element was mounted to the hood.

C3 small-blocks all used a flat hood (except the '70-'72 LT-1, which used a raised big-block hood), big-blocks used a raised hood, and the '68-'69 L-88's used an even higher raised hood.

I'm not sure if I understand what you are saying, but here's what I get out of the above post. So, you can virtually put any small/big block in any C2/C3 Vette. The "fitting" problem would come in the placement of the carburetor and the intake?

If I'm right in my understanding, then how do you get by the "taller" carburetor and intake problem if you don't have a higher and raised hood on the Vette?

Like I said, I'm not sure if I understand what you are saying, but I think I might. Thanks!

 

[Evolution1980]

Here's a 1969 L88

I took these pictures this past summer.

You'll notice the hood bulge is taller and stays that way all the way back to the windshield.

The L88 is the only factory vette I know of (besides the ZL1) that has this type of carb/air filter setup

Notice the filter screen built into the hood of the car...

And these are some pics of my garage where I store my vettes...

 

[Stallion]

Evolution, what year is that red Vette? Was it originally with an L88? Oh my, where is this garage that is filled with all of these old Vettes!? My draw dropped when I saw those pictures.

 

[Stallion]

Nevermind, I see that it's a '69 Vette. The '69 has many of engine options. Many BB, with the 427 options. Very nice! Man, I would love that Vette.

 

[Evolution1980]

Nevermind, I see that it's a '69 Vette. Very nice! Man, I would love that Vette.

It can be yours for a cool $100K

 

[Stallion]

Evolution, I read "It could be yours" and my heart skipped a beat, and then I read "for a 100K" and then I realized. Ah, you ol' trickster!

 

[JohnZ]

If I'm right in my understanding, then how do you get by the "taller" carburetor and intake problem if you don't have a higher and raised hood on the Vette?

Like I said, I'm not sure if I understand what you are saying, but I think I might. Thanks! [/B]

You buy a taller hood.

 

[Stallion]

I see that on the L88 (and example) that the air filter is at the very top and actually a part of the hood, but how would the carburetor and intake manifold be as in relation to each other? For instance, you said that the taller hood would be needed as a result not of the block, but of the carburetor and intake placement. How so?

Thanks!

 

[Tom Bryant]

High performance intakes are taller physically to give longer runners and a more direct intake trajectory at the intake valve. Ram effect, if you will. Plus the top of the block on a big block is higher in the car due to it's physically bigger size. Both of these factors contribute to the final height of the carb.


Both small block and big block mount in the frame at the same location and in the same manner.

Tom

 

[Stallion]

I see. So, if you have the higher (and longer running) intake then of course the carb would have to be there to induct the fuel, so that's what you mean by the higher carb/intake manifold due to the bigger block.

I understand now! Thanks!

TR