I need opinions on this 318 build

hoosierdaddy said

Let me start over a bit , the car is an unfinished project that i recently purchased . The PO rebuilt the motor and had a 727 transmission built and then installed everything . I only have basic info on the motor build . Nothing was plumbed so I got everything done so I could break in the cam and just check the general health of the motor . As far as gears the car has a bone stock 8 1/4 . What I see in the future is no more than 3:91 gears and really leaning towards 3:55 if I can make them work and 15" wheels . Primary use will be street /cruise with occasional track time .

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Based on the latter idea of 15" wheels/tires and 3.55 rear gear, mill those heads as much as you dare and go pretty small on the cam.... like in the 248 to 260 advertised duration range IMHO. I also suspect that a TC change may be in order if you go with 3.55 gears and these tire..... the engine will be barely turning enough RPM's to get to a 2600 RPM TC lock at 60 MPH. The 3.91 might be a better choice just because of this; I would not normally even think of a 3.91 for street use, but you're stuck in a tight corner of the performance map to start with, with that low SCR. And, it kinda depends on your streets, and speeds and how you like to drive.

Once you go to the smaller cams to move the start of the torque curve down, then the top end RPM drops. If you make the cam big, then the low end of the torque band moves up in RPM as the top end moves up. Either way, the price paid for a low CR is a smaller than average max to min useful RPM ratio; that works in some racing formats but is a substantial disadvantage in typical street use, where a flexible engine with a wide RPM range is pretty handy....