The lack of water flow through the intake presented no problem for the intake swap, but the bolt-hole alignment required attention. The Gen-2 LT1 featured reverse cooling, meaning (among other things), dedicated head casting with different intake bolt patterns and no coolant passages in the intake.

The big hurdle for this test was the fact that the Gen-2 LT1 intake and heads featured a different bolt pattern than the previous (conventional) SBC intakes. The most obvious answer to adding torque was with displacement, and GM did exactly that by offering a larger, more powerful 5.7L version of the LT1.īut what about the 4.3L folks? Besides, we have always wanted to compare the previous generation, long-runner, LB9/L98 Tune Port intake to the later, short-runner LT1 intake, and this was a perfect opportunity. And adding torque to the little 4.3L is what this test is all about! Swapping Intakes to Make More Torque What the little V8 needed more than anything was additional torque. Why did GM use the smallest small block in one of the largest passenger vehicles? More importantly, why did GM use the torque-lacking, short-runner, LT1 intake on the smallest V8 ever offered in the biggest package? Nope, the L99 was a gen-2, LT1-based 4.3L V8 offered in the (of all things) full-size Caprice Classic! What? A 4.3L V 8? Don’t you mean the 4.3L V 6? Not quite as legendary as its larger brethren, the L99 was actually a diminutive 4.3L V8. Note: We’re NOT talking about the LS-based L99 here either. For instance, most Chevy fans recognize the famous ones, like DZ302, L88, or LS6-and some of the real diehards even know the difference between the LT-1 and LT1 (first and second gen performance 350 motors). What the heck is an L99? We know GM uses these alphanumeric designations to label its many engine configurations, some of which were more notable than others. What the little LT1-based L99 4.3L really needed was some Tune Port torque! (Image/Richard Holdener)

Lt-1 cam 350