Conversion - Fit and Clearance-Engine

Once the car came back from the frame shop, the first step involved pulling the old engine and test-fitting the new one. Ron from Lone Star Chassis Fabricators, of Abilene, TX did the cutting and welding. The stock LT1 manifolds are cast-iron with a stainless steel shroud and exit approximately where the 305 Monza manifolds do. They looked like they would fit in the car, but once we got the engine in; the left manifold was rubbing against the steering shaft. Also, the "dog ear" plate where the exhaust mounted to the headers needed to be cut along the left side. We possibly could have dinged the steel shroud on the manifold, but it did not appear that would provide enough relief and might have cracked the cast iron part. On Tony’s recommendation, I purchased Sanderson CC-13HO headers. The HO’s are matched to the D-shaped exhaust port of the LT1 heads. That brought in a new problem—I planned on running the EGR system in order to assure a smooth idle. The right stock manifold has provisions to mount the EGR tube. I also needed to install oxygen sensor bungs in either the collector or head-pipe just below the collectors. I decided I wanted the oxygen sensors in the header collector so the engine could be pulled as a unit. The EGR mount and boss was a little trickier, but it welded into the other side of the collector and the tube mated perfectly in the same position as the stock manifold.

The engine was obviously sitting too low in the engine compartment. The crank pulley/balancer was sitting only a fraction of an inch above the front anti-sway bar after the K-brace modification. The right steering knuckle hit the oil pan about ½ inch from the bottom even with the built-in notch in the stock pan. It was obvious the engine needed to be raised. The good news about the LT1 is it has a lower deck height than any previous small block Chevy. So it was an easy fix to add ¾ inch steel spacers to the Monza frame mounts and raise the engine to where the steering completely clears the oil pan without cutting or dinging it. My steering shaft goes through the headers and clears the left side headers side-to side, but the steering column and shaft were raised ½ " and u-joints were added to get a clear shot over the fourth tube and through the first tube. Tony’s engine did not sit as low in the car, so he did not add spacers, but still wound up modifying his oil pan to clear the steering knuckles. We both had to relieve the LH #4 tube to get the steering shaft to clear the headers.

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