On an April Sunday morning the engine was placed in the dynometer bench and after replacing the dead MSD e-curve distributor with a more reliable one it was fired up. The motor was broken-in using altering RPM for about 20 minutes after which the oil was drained and the oil filter removed for inspection. Nothing special was found. Once the engine had cooled during the lunch break the head bolts were re-tightened, fresh oil filled with a new filter and the actual tuning of the engine would be started.
I must admit that my role during this event was more of an assistant. The owner of dyno and my friend that I had with me took care of all the analyses and decisions what to do next. The engine ran nice with the initial set-up but they were not happy with the air/fuel ratio (AFR) on the 5-8 cylinder bank. After changing jets and checking the fuel pressure and some other thing it was decided that we would try it with an other carburetor. The Holley 570 Street Avenger was replaced with a Holley 750 which gave a similar result. Also a couple of carburetor raisers were tested but the symptoms remained until a Holley 670 (#0-81670) with 1" raiser gave a result good enough. Now the engine was ready for the serious pulls. During them a couple of different ignition curves were tested until no improvement was found. Maximum advance was set to 32 degrees at 4400 rpm.
My initial target when beginning the motor project was 'to have as much power as the Shelby Mustangs had in 1965' that being 306 HP. My friend who has dynoed several engines estimated that this one might reach peak power of 350 HP which was hard for me to believe. I'd be happy with anything exceeding 300 but - to be honest- disappointed if it would remain under 300. We both were surprised when the result was:
My initial target when beginning the motor project was 'to have as much power as the Shelby Mustangs had in 1965' that being 306 HP. My friend who has dynoed several engines estimated that this one might reach peak power of 350 HP which was hard for me to believe. I'd be happy with anything exceeding 300 but - to be honest- disappointed if it would remain under 300. We both were surprised when the result was:
Peak power 380 HP @ 5400 rpm
Max torque 545 Nm @ 4600 rpm
We did not rev the engine above 5500 rpm as it was easy to see that the curves were coming down. This would be the best that the heads would be able to do as well. I was happy with the result but more than that I was happy that everything went fine, the engine is now ready to be placed in the vehicle and even more happy that I have friends that have helped me with the project.
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| The torque curve exceeded expectations |
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| 380@5400 and 545@4600 |
