Dyno Testing
We wanted a good baseline to begin with. We know through past testing that typical 150,000 LT cars make about 225 rear-wheel horsepower through a six-speed, and that corresponds pretty well with their 285 advertised horses at the crank. Assuming the extra cubes we were running would add about 30 horses to the stable, that would set a baseline goal of 315 hp in otherwise stock trim. With a bushel full of cams and a team ready to burn our hands in the name of horsepower, we set out to Shackett Automotive in Nashville to strap our engine to their Superflow 901 dyno.

We started up our little stroker with the complete Edelbrock LT4 system, including the 218/218-at-.050-inch camshaft. The cam is relatively mild mannered and the engine fired up right off the bat with just a lovely hint of lope. A glance at the computer screen revealed the manifold vacuum at idle was a near-stock 28 kPa. After bringing the oil and water temps up, we dropped the hammer on the dyno and were stunned with the results: 430 hp and 461 lb-ft of torque. We were not expecting those kind of numbers. Granted, the Edelbrock heads flowed pretty well, but with the docile cam just bumping along, we didn’t expect the combo to pick up over 100 hp from stock! We couldn’t wait to bring on the bigger cams.

We popped off the valve covers and the COMP Cams rocker arms and got busy installing cam number two. COMP’s 503 cam is one step bigger in duration than the Edelbrock cam. With 224/230 degrees at .050 inch, it would have a slightly more noticeable idle but still work with the stock 24-pound injectors (though pressure was raised to 52 psi from 43) and satisfy those wanting the sleeper effect.

We set the preload on the COMP Cams hydraulic roller lifters to zero, and brought the engine back to life. Again, wow! It pegged over 450 hp without breaking a sweat. This was moving steadily into big-block territory with just a basic bolt-together small-block.

This was a 377, not 350, and my cam is 219/227.

Posting has been minimal because I’ve been waiting on those damn heads to get shipped.  I did talk to Trick Flow recently, and they said there was a tooling problem, and that it had been corrected.  SUPPOSEDLY, I was the next on the shipping list, and there were a couple of heads on the shelf that were going out soon.  They’re right down the road from Summit, so it’ll bounce through them in a day.  I hope.

I’m calling back on Monday.

Pictures of the roller rockers are on my camera; I’ll get them up sometime soon, I hope.

I’ve got my last sailing class this weekend, so I’ll be out all weekend afk, but should be back next week to finish cleanup and hopefully get some pictures of the heads up!  I’ve got some new engine cleaner, so I’m also going to give that a shot.


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