2-bolt or 4-bolt?

[Scooter76]

Are L-48 motors 2-bolt or 4-bolt main blocks? Corvettes have usually always recieved 4-bolt blocks, but I'm not sure in the case of the low hp. L-48. Thanks in advance.

 

[Jack]

L48 = 2bolt. Vast majority of street motors will do just fine with 2bolt ... sbc 2bolt'll easily handle 400hp.
JACK:gap

 

[Stallion]

Yup, the L48 is a 2 bolt. As he said, a 4 bolt isn't necessary at all, unless your crank is putting out some major power. Only necessary for extreme power and racing.

I don't know about earlier small blocks though. What is the LT1? I assume a 2 bolt also? Anybody know?

 

[Tom73]

The base engine Vettes, like the L48, are all two bolt mains. Genrealy the optional high performance small blocks, like the LT-1 and the L-82, are 4-bolt mains since '69. All chevy small blocks prior to '69 were "only" 2-bolt mains.

tom...

 

[Stallion]

The L82 is a 4-bolt main!?

 

[Scooter76]

Thanks guys! The 2-bolt blocks are supposed to handle 500hp with main cap studs. So they are fine for 99.9% of the street aplications. I just wasnt sure if the L48 was 2 or 4. On the Lt1's (late model) the vettes get 4-bolt & us F-body owners get ripped off with 2-bolt mains.

 

[Tom73]

The L82 is a 4-bolt main!?

Yep

 

[Stallion]

I believe you about that, but I can't imagine that the 4-bolt is necessary for the power of the L82. I'm sure a 2-bolt would have been fine, right?

 

[Tom73]

The L82 is basicly a lower compression version of the old 350ci/350hp engine. In fact uses the same exact cam. The L82 also has a very strong lower end with the 4-bolt main, forged crankshaft, and Alum. impact extruded pistons. In addition to the strength of the lower end it also uses the big valve heads like the LT-1. In fact the '73 L82 is only 5 hp less then the '72 LT-1 and in magazine tests of the day they were dead even on performance.

tom...

 

[Stallion]

Yes, but that's the '73 L82. What about the '78 L82 which only put out 220 bhp and 260 ft./lbs. of torque? Do all L82s have the 4-bolt?

 

[SwaveDave]

Some BB Corvettes were even 2 bolt...as well as 4 bolt.

 

[Stallion]

Of course, because the big blocks are known for their gobs of torque, and many times that 4-bolt is necessary. But an L82 in a '78? Hmmm....not sure if that's totally necessary.

 

[GerryLP]

Check out this web site for this kind of information. One drawback is that you need to locate the block casting number usually on the aft-left side of the engine block near the left cylinder head end.

Mortec

And additional engine block decoding information can be found in ...

NastyZ28.com

This beats removing the oil pan and checking the main caps...:L

 

[Tom73]

Of course, because the big blocks are known for their gobs of torque, and many times that 4-bolt is necessary. But an L82 in a '78? Hmmm....not sure if that's totally necessary.

The 78 L82 is the same engine as the 73 L82, just that it is choked down with single exhaust, cat converter, and tighter emission tuning on the carb and distributor.

Necessary, who knows, but, boy, talk about a great starting point!

tom...