If you want 700+hp on pump fuel n/a, yeah. But a built 572 would be very expensive. If the goal is 500hp, a stroked small block will get there. There's even guys pushing 500 at the crank in n/a 331/347's that aren't that wild.

And the big block is heavier with internals that rob more power....so the same measured output from a small vs big block, the small block will perform better because of faster engine response and lower vehicle weight. So you need to really be putting power out of a big block to justify the extra performance loss, which typically means going well beyond what most cars/drivers can ever handle on the street.

In the end, it's typically cheapest to build what you already have, or can easily get. Big blocks are a way to make good power pretty cheap, if you already have or can get one that needs little work. And getting 500hp out of a 460 with stock heads isn't that difficult. But a 500hp 347 Mustang will beat down a 500hp 460 Mustang almost every time.

People get way too hung up on power numbers or cubic inches, and don't pay enough attention to performance. Build for efficiency...you build 2 engines to the same level of efficiency within a similar rpm range....bigger engine wins every time. But just building a bigger engine isn't necessarily going to make you faster. Efficiency costs money, regardless of the engine.

 

I understand your point very well i know the power that a small block can put out and with less weight i built a 347 in college and it was very impressive even beat most the small block chevys that guys brought in and built up almost beat a 400 but fell short because the rocker arm came off the stud. Too short of a stud and there wasnt any time to fix it to see if the motor could put out more. I was mostly sticking to a big block because thats what i got right now just sitting around got the 390 with a fmx for only 400 bucks and the internals looked great.

 

Like I said, it's cheapest to build what you already have. The goal in any performance setup is to get the most amount of power for the given amount of money. If you already have a 390, then build that up. In reality you'll prolly get more performance for what you spend building that engine, then if you go get a SB, get heads etc etc etc.

If you have the money, some good aluminum heads, custom hyd roller cam, make tons of power.

 

After i get everything settled in and any problems figured out i'm going to start looking into a good set of aluminum heads and have been wanting to do a roller conversion.Thanks for all the help im gonna try the 445 stroker kit when i can and a set of aluminum heads along with the cam.

 

Keep in mind that 445cid needs a lot of head.

 

Absolutely, but if you're going with a 572 is has to have a blower on it (sorry its a chevy)

 

67mustang302 what heads would be a good choice?

 

Start from here?


Norm

 

Head choice depends on application and budget. You have to do your homework.