How much power will a stock 4.6 handle?

If I did a Kenne Bell, headers and exhaust do you think a stock 4.6 would hold together? BTW this car won't be raced much. Maybe 3 or 4 Sundays out of the whole year.

Most people have been saying around 8-9psi is the most power you can get while still being safe. With those mods you could probably be in the 450-500ish rwhp range depending on the psi you choose. A lot of people on this site have been saying if you plan on going over 450rwhp that you need to think about some supporting mods. Someone with a roots-style blower or that knows more about them could probably help you better though.

The block is good up to 600 hp, and the rods and pistons up to 400 hp.
http://mustangandfords.com/techarticles/mufp_0509_swap/

Hate to break it to ya but real world experience has proven the 400bhp mark a bit low for the rods and pistons. Most breaks are occuring at 450rwhp, this is a bit more than 500 at the crank, and being forced fed of course to reach that power level.

The block can also handle quite a bit more than just 600. We will begin to see how far it can safely go before the end of the next racing season.

And that article you posted... its a good read on factory modular engine design and history but it doesnt offer anything more than that.

Anyways, for the "long run" dont plan on driving around with more than 450rwhp on the stock rotating assembly, this is what I expected the limit to be and the engines have been breaking at about that level (the rods are over stressed).

One forum fella lost his motor at the end of his SECOND DRAG RUN at only ~460rwhp. He knew it was going to break but just didnt think it would have gone that soon.

-Dan

So those mods would probably be to much for a stock bottom end? Even 99% of its life was on the street?

If you want to be sure that your motor isnt going to fail I say stay away from that 450rwhp mark.

-Dan

lets say I want 100 more horses than stock, what do I have to do to my motor to keep it well within the "not gonna crack" zone?

According to Steeda in a recent mustang monthly they dont recommend going past 425hp. Anything more than 425 and your just waiting to buy a new motor.(page26 dec 2005 issue-"weak wont survive" side article.)

Also watch where you read numbers. 450rwhp on a Mustang Dyno would be nearer to 480rwhp on a Dynojet dyno.

Everyone I've talked to said don't go over 400RWHP without building up the bottom end. Even so, if you are going to put a blower on it I would build it up anyway to be safe. Maybe not right away, but next time you get some cash that would be the thing to do.

So which one is it - no more that 450 hp, less than 450 hp, or you have no idea?

i would say 425 is safe. 450+ is bad news. Mine blew at 462.

are you talkin 425 at the flywheel or at the wheels?

Wheel.

Just buy the Saleen blower ($3,999) and get 400 HP out of the motor with only 4PSI

where can you get it for $3999? best price i found is just over $4500.

Sorry, that is a typ-o. It is $4,999 right from the Saleen website.

I was thinking about my good old "easy & cheap to mod" car. But regardless, the higher the PSI, the more heat generated by the S/C unit. So the Saleen kit is really nice because it keeps the intake charge temperatures down.

if it never and i mean NEVER sees detonation and you dont hardly drive it hard and it has a realy safe tune I have seen them make almost 500 rwhp reliably .

but there is NO margin for error at this power level and you are playing with fire.

I can't count on my hands and toes the number fo 4.6 cars that started knocking within a month of makeing more then 450 rwhp on our dyno..

i can count on one hand the cars that have survives long term at 450 plus rwhp

the joke about 4.6 motors here at the shop is .. when you put a blower on the check engine light becomes a change engine light.

and these are all cars setup safe with to 11.5-1 af ratios and very safe timing numbers.

I was gonna get a procharger but now I'm not since I don't have the money for a new block right now. Procharged motors seem to be popping regularly now. If I was going with a blower I would go with somthing more mild,like the saleen. I'm gonna try to get 400rwhp off the spray till I can afford a new block.

please excuse the newb question, but how much does a new block go for that could handle say 500+ hp? and is that all you would need or would you need to replace pistons and rods too?