quote:Originally posted by jackcarter1971:
... Looking for a good reliable engine, with plenty of torque, and some good top end. That is not gonna cost me a fortune. I do not want to over engineer the engine, it's not ever gonna be a show car. Unless you call driving as many miles as I can on the weekends showing off the car ...
Boss Wrench's advice is very appropriate. Your comments lead me to believe you want a strong performing street engine with some durability built-in so you can work it hard. This is probably the type of engine the majority of Pantera owners need.
So what do I recommend?
There are several choices still to make; several questions to ask. But consider this, we can juggle camshaft duration and engine displacement to build towards a certain horsepower goal over a certain powerband. For instance, the following 3 motors have roughly the same streetable power band:
Displacement .......... camshaft intake duration (degrees @ 0.050" lift)
351........................225 - 230 (~400 BHP)
377........................235 - 240 (~450 BHP)
408........................245 - 250 (~500 BHP)
The larger motors will make more power than the 351 even though they have the same powerband. It sounds like Jack may have you talked into staying with 351 cubic inches, if so, I agree whole heartedly.
Since you mentioned wanting a good top end my next question is do you want to run hydraulic lifters, or is that top end important enough to you that you are willing to adjust a set of mechanical lifters from time to time?
The iron 4V head will "hit" harder and harder as we put a bigger cam in it. That affects drivability. One way to smooth out that hit is with a custom ordered camshaft having wider lobe centers than what is the current trend. The drawback being less "peak" horsepower and a demand for less compression (less compression = less horsepower). I don't see that as a drawback personally. But the wide lobe centers also make the motor less finicky about the exhaust system. This could be an advantage on a street motor where you want to keep it quiet. Another way to smooth the hit is to employ a more restrictive exhaust system, the drawback is the exhaust system will rob top end horsepower. The advantage is the exhaust system is quieter, something very important if you plan to spend a lot of hours driving the car. Another way to smooth out that hit is with small port heads, like the CHI 3V or 4V heads. A second advantage to such heads is that they are made of aluminum and have modern high swirl combustion chambers. This makes the engine lighter and allows you to run about a point more compression, which makes more power.
I would like to read your thoughts on the cam, the exhaust and the aftermarket heads.