We're talking about engines here: Would it be less expensive to run a lower-compression engine with a belt driven supercharger, or build up a high performance naturally aspirated high-reving engine? I know that certain parts (like valvetrain, intake, etcetera) would need to be upgraded for both routes. The engine I plan on using is a 1969 351w, and Im looking to get about 450hp at the crank. Thanks!

 

you can get the 351 up to 450 at the crank without breaking the bank. if i were you, i would rebuild it to a 408 stroker (about 1k for the whole rotating assy) some good heads, theres thousands out there, and a rpm air gap or the like intakes, maybe even a vic jr intake

 

I agree. Blower builds can be costly, and 450hp out of a windsor stroker isn't hard to do. Ask Urban

 

Are we talking a street car or a strip car? At what rpm are you wanting to make this 450hp? I can build a motor that is 450hp, that you could never drive on the street b/c the power band is in the 7ks. From my experience, you should be talking about torque goals (or at least include that in the conversation) if this is a street motor.

It is not hard to get 450-500hp out of a 351, but it is not cheap. If you are going to build power high or build power low, you still need great parts and materials. Getting good materials that will hold up to power & torque is not cheap. If you are going to drive 450hp 500Ft*lbs of torque on the street, it is going to run high b/c the material to make it last are very expensive. I can build a motor for a few $k running 500hp with power adder like nitrous or a turbo that will work fine on the strip, but would never last on the street. Mileage and power work against each other.

A NA small block street motor that will last 100k miles, is going to cost $15-20k for the motor (not including all the other stuff you need to do to run that much torque). I have been through it and know exactly what it takes and costs. If you skimp on rods, block, pistons, connecting hardware, etc. yes you drop the cost but you are also dropping the life of the motor. If you say I will start with the motor and then do the rearend and tranny, you are going to break down. Believe me !

To answer your question, I would think the blower setup would be more expensive b/c your motor is going to cost the same regardless of which direction you take. With a blower setup, you have the added expense of a blower. Really a no brainer. If you can get the torque naturally, it is cheaper to do that with the exception of nitrous which is very cheap power.

If you are serious about this project and have the money, I would love to pass on my knowledge as you need it.

 

Cheapest, N/A

 

Yea I plan on using the engine in a street car, so obviously an engine running 7k rpms wouldn't work too well. I knew the cost would be high, but 15-20k$?! I could buy a brand new crate motor for that, with a warranty!I WAS thinking more in the 5-10k$ range, because I was under the impression that it was do-able to build a long lasting, reliable motor for that price. Is that wrong?

 

No, that's OK. You can do it under 10k. Stroke it to about 400 cubes. Don't need a forged crank or H-beams. Get a good set of heads and a nice cam. 450 hp out of a 400 cid isn't to hard. A little more difficult with a real 351w, but still possible. Should be able to keep it under 6500rpm.

 

yeah, IMO you should be able to do it around 6k +- 1k

 

bottom line- 400hp with a 351w is relatively inexpensive. anything above that begins requiring more costly modifications. whereas, you could simply start with forced induction and get 450hp without anything extraordinary. another benefit, is that usually doesn't affect low rpm drive ability. it just likes more fuel.

 

do a 408, it is pretty easy to get 475-500 streetable hp out of one. I went 351w to 408 and BIG difference and even with bigger cam idle is almost the same, I increased the cam by 20 degrees duration (custom) and its almost as tame as my ol 351w but about 125-150hp more.