Corvettelvr73

I have a 1973 with an L-48 motor. Does anybody know if it is a 2 bolt or 4 bolt main block? Any help is needed?
And also what is the difference in the two?

fauxrs

Te L-48 is typically a 2-bolt motor. Not that this should worry you as the two bolt can handle a whole heck of a lot more than most people give it credit for. IMO, for a street motor the only advantage to a 4 bolt is bragging rights when bench racing :lol:

Budman68

I think the only need for a 4 bolt is high rev'ing and brutal torque motors. A 2 is perfect for street apps.

Tom73

In '73 the L48 was two bolt and the optional L82 was 4-bolt. Only differences in the block is that the L82 has 4-bolt main caps on the three center main caps. The L48 has 2-bolt caps on all 5 main caps. But engine differences are alot as the L82 has heavy duty components in the crank pistons etc.

As has been said, the 2-bolt should hold up okay for most any street application. Now if you are running NOX or supercharger you will probably want to go with 4-bolt mains.

tom...

Shark Racer

Anyone have any ideas how the GM GW 350 compares to the L-48 block? I know the LM-1 has a 4-bolt main, but not sure about crank and rods and all the rest.

Smokehouse69

Standard truck parts in the GM crate motor, cast crank, rods and pistons. At least that's what the guy at GM told me. ZZ-4 has forged crank.

dladd74roadster

I have heard of some L-48s that had 4 bolt mains. Here's the way the story goes:

If there was a shortage on the line, they would substitute L-82 blocks and use L-48 internals. But they NEVER were allowed to substitute an L-48 2 bolt block for an L-82. I have a feeling that there weren't that many 4 bolt main L48s though.

dl

Tom73

The blocks were the same except for 6 extra holes for the three 4-bolt caps. Would have been very easy to use the L82 block but use the 2-bolt caps and leave the 6 extra holes empty :rolleyes: Why use the more expensive 4-bolt caps on the L48?

tom...