vcole@metrocast.net

What is the difference between a 69 L36 427 and a L68 427? I know some of it. I know the L68 is a LQ block and that it has tri-power but what are the other differances with the engine? What are the differences between a L36 and L68 car? They are both 4spds.

thanks
VC
:cheers:

SBR

Other than the tripower setup, they are the same engine. As far as the suffix code I am not sure.

rainman69

[edit] Due to premature senility...I have made a comment in error. :jester

So, nevermind what I said before. :cool:


[Modified by rainman69, 11:45 PM 3/1/2002]

corvette kid 427

Listen up if you want to know the difference between the 390 horse L36 and the 400 horse L68. The only difference is the tri-power combination found on the L68 and its code on the build sheet. The L68 is not a 4 bolt block. It is a 2 bolt block and if anyone doubts me, stop by my garage and have a look at my 69 427 L68 motor. It is stripped down and waiting for a stock rebuild , then life in storage. A 700+ horse 540 and Jerico DR4 will rest where the 427/M20 once rested. Keep em lit, corvettekid427.

andyg

I thought I had read somewhere that some of the blocks were 4 bolt and some where 2 bolt, depending what was on hand at the time. I forgot where I had read this, but there was no external markings differentiating the different blocks, only pulling the bottom pan would reveal what was there.

--ANdy

corvette kid 427

Andy, the easiest way to check if a block is 4 bolt or 2 bolt is to look at the driver side, rear area of the block. The 4 bolt blocks had additional holes drilled above the oil filter boss for an external oil cooler, hence the name side-oiler. The L36 and L68 were only produced in the 2 bolt style whereas the L71,L89,Ls6 and L88 were produced with the 4 bolt block. If anyone does have a 4 bolt L36 or L68, they have an extremely rare piece but I would highly doubt it.

Rowdy Rat

The difference between the L-36 and L-68 was the induction system... That's about it.

The L-68 engine wasn't really an engine option at all, although it is listed as one in most publications. Like the L-89 (aluminum cylinder heads with L-71) and ZL-1 (aluminum cylinder case with L-88), the L-68 was more of an engine accessory option. A person wishing to have the three two barrel carburetion on oval port head/hydraulic cam engine first had to order L-36... Further adding L-68 got you the carbs. Both L-36 and L-68 will show on an original window sticker when a car is so equipped (the actual option description should read something like "CONVERT 390 TO 400HP").

Because the L-36 and L-68 both start out as the same engine, they both use two bolt main bearing caps. I am told that there is one documented instance of a four bolt main block being substituted on an L-68 due to inventory shortage of two bolt blocks. This was a single instance in several thousand cars built with this option... It was the exception, not the rule.

Regards,

Larry B.

I have a late 69 with a "512" block It was used for 390,400,430,435hp. This block was used in '70-71 454's I haven't had the pan off so I do not know if it is a 2 or 4 bolt . :chevy

Flareside

I've noticed a few other things, since my 3x2 car was originally an L36.

1. They use different fuel pumps and fuel filter arrangements.
2. The 3x2 car only has one fuel line running back to the gas tank. The L36 has both feed and return lines running along the frame. I'm not sure what Chevy did back at the fuel tank with the extra return fitting on the tank. Cap it on the 3x2?

-Joe

CanadaGrant

Sorry for the eleven year old reply... I have a 69 L36 427/390 that is numbers matching to the car and it has 4 bolt mains. It is a late build October 24th car that is all original and the motor has never been out.

1wicked55

My numbers matching late build Nov 3 L-36 is a 2 bolt main

CanadaGrant

Kind of weird. I think GM was just using whatever they had on hand at the end of 69. My build date is October 24th and the motor has never been out of the car. I pulled the pan to replace the gaskets and it's 4 bolt.

restoman1

Mine's also a 2 bolt, but I've seen 4 bolt L36's and L68's as well. Chevrolet protocol dictated that a 4 bolt block could be substituted in a 2 bolt application, but a 2 bolt block could NOT be substituted in a 4 bolt application. It didn't happen a lot, but you see it now and then.

Ed

garygnu

with the 454 block coming soon ,they ,GM probably wanted to use up all the 427 blocks they had .

CanadaGrant

Thanks again for the info Ed. My last 69 was in 1970 and this is like going back in time. My wife was 3 years old when it was built and it's her car. I just play with it.

The block is vin dated to the car but is 4 bolt. When I pulled the pan I was kind of shocked. Even the original clock still works in this old thing and it is straight as an arrow. It's 4 bolt from the factory and is a 427/390.

restoman1

Gary, the 1969 427 and 1970 454 engines used the same block, the 3963512 casting so there was no reason to use them up. Seeing a 4 bolt L36 or L68 is just one of those things that happened.

Grant, having an original clock that still works after 45 years is unheard of! Usually the contacts lasted a few years at best. Clocks were NOT one of GM's best designs!!

Ed

1wicked55

That's funny because my clock still works perfect. It's probably because I got stuck with a 2 bolt lol

CanadaGrant

I was shocked. The clock was unplugged and I just plugged the harness back in. It worked and actually keeps pretty good time. I still shake my head when I look at this one and it isn't a replacement. It's the original 45 year old clock and it still works.

CanadaGrant

See? Another guy with a working clock!
How do you know it's really a 2 bolt......?

1wicked55

My matching number motor is rebuilt stock and on a stand waiting.