Thread: SBC differences...

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What are the major differences in the different SBCs? Let's say, for sake of argument, that I want to change from one SBC to another, what issues would I have?

LS-1 vs LT-1 vs Vortec 5.7 vs standard old skool 350 vs 400 and so on. Are they interchangable?

I think the only major difference is:

the lack of side motor mounts before '58,

the 62-67 novas had a difference in provisions for clutch linkage, and a front oil sump bracket, (they also have a different bellhousing for standard trans),

and the "big one", that 400 smallblocks are externally balanced, so they use a different front balancer, and flex plate/flywheel.

If I got any of these wrong, someone correct me.

Originally posted by HOTRODPAINT
I think the only major difference is:

the lack of side motor mounts before '58,

the 62-67 novas had a difference in provisions for clutch linkage, and a front oil sump bracket, (they also have a different bellhousing for standard trans),

and the "big one", that 400 smallblocks are externally balanced, so they use a different front balancer, and flex plate/flywheel.

If I got any of these wrong, someone correct me.

So theoretically if I have an LS-1 in my car, then I could swap it out for a 400, or a Vortec out of a pickup truck? Remember, this is theoretical here...

The major differences between an old generation 350 vs. a LT-1/LT4 are reverse coolant flow, cold water from the radiator enters the head before travelling through the block. This keeps combustion chambers cool for lower octane requirements. The engines ran 10.5:1 to 11:1 compression ratios on pump gas. LT engines have camshaft driven water pumps. LT engines have altered intake runner and manifold geometry for better flow and increased turbulence in the combustion chamber. LT engines have roller cams. The internals were very similar to the old 350s and many of the parts are interchangeable. They have a distributor drive but no fuel pump drive.
The 5.7 Vortec engines used a conventional coolant flow but had heads modelled after the LT-1. These are the heads you buy from GM to bolt on to your old gen small block.
LS engines and the new generation Vortec engines have very tall and narrow intake runners for an even straighter line into the combustion chamber. They all typically run smaller bores an bigger strokes to get similar displacement to the older generation engines but with more efficiency. They are reverse coolant flow engines. All of the bearing sizes have changed for longer life (you don't see many Vortec 5300s with oil pressure problems). All of the engines use roller cams. There is no distributor drive of fuel pump drive.

Motor mounts for the LS, new generation Vortec, and LT engines are changed so they are not direct bolt ins. Oil filter location and bell housing bolt holes are identical to the old generation blocks, so installing one in an old engine isn't too difficult because the only thing that does need to be changed are the motor mounts. You would have to carry over the computer and fuel injection from the donor motor for any LS and new Vortec engine because of the lack of a distributor drive, unless you wanted to rig up some sort of crank trigger.