This is in my Ford 302 reference book... If you're careful with your maintenance and don't romp it too often, you can probably get some decent time out of your block with that amount of HP.
I have seen some pics on the net somewhere of a small block ford that looks as if were sawed in half....can't seem to find them now though.Scarry!
As mentioned above, the late blocks are actually a good bit weaker than the 79 and earlier blocks due to thinner main webs and decks. You hear rumors about certain blocks having a higher nickle content. Even people within Ford disagree about which ones did or didn't. Maybe the 289 HiPos, maybe the Boss 302s, maybe Mexican blocks, but definitely not 5.0 blocks. Ford made them as light and cheap as they could. I've heard a well known engine builder describe them as " weak-suck". Then, to make matters worse for the 5.0, they lightened and weakened the crank and added 50 oz imbalance dampers and flywheels. That's almost twice the imbalance weight spinning on the ends of a weaker crank!
well i have the exhaust and headers. i know i need a good cam... i was thinking of a xe268h .512 lift both sides. and a rpm intake.. and i know i need heads.. i was thinking the victor jr cast iron heads.
So, 400 "FWHP" then. Again "FWHP", I assume. My engine put out 350RWHP (which is debateable also - as dyno's differ - but we'll use it for converstation sake). Quote from the tuner, "You probably have at least 15% parasitic loss in the drivetrain - maybe as much as 20%." I've heard the same numbers from others so I wasn't surprised. So, assuming I have (conservatively) 15% more horses at the fly wheel - that would make my engine have, say, 400 FWHP. I asked the tuner, "Knowing what the horse power is now, how much nitrous do you think I could SAFELY throw at it?" His reply was, "You should be safe with a 150 shot and an occassional 175 shot using a plate system". That said, and assuming a "shot" is FWHP and not RWHP, he's saying that my block is safe to 575 FWHP. This is coming from a very well respected Performance Guru (FWIW). Note: My roller engine is zero balanced and uses all forged components, including a Main Stud Girdle. The block should be the weakest link. I have, in fact used a 200 shot on this block (when it was in my Mustang). Granted, the heads and intake were different (less efficient Windsor Jr's and a Cobra intake). I sprayed a 150 shot on it several times. If the 420 hp is FWHP, and according to your satement, and if we were both using forged rods, I shouldn't put any nitrous on my engine (being only 20 horses shy of what yours let go at). Were you using forged rods? (please tell me "No" ).
That almost sounds like my setup...I didn't know I was that close to decent horsepower. Where does the compression come in on that? Based on my description, what do you guys think I am pumping out (8:1 compression, P heads, smaller cam than described above and flat tappet )? I know it is the fastest car I have ever driven... Just for the helluvit, I think I might take mine to the local dyno (now that I know where it is, thanks to Mr. Book) and spend the $75 just to know. But that will only give me RWHP, then I still have to guess FWHP...
I'm suprised a knowledgable tuner would say that. Drivetrain losses aren't percentages, they are pretty much fixed values depending what parts you're using. If an engine makes 300 FWHP and looses 15%, 45 hp, through the drivetrain getting that power to the ground, does that mean a 600 FWHP motor in the same car with the same drivetrain will loose 90 hp? I don't think so. I've seen lists that have the average expected losses for different trannys, rears, u-joint angles. My T5 is expected to loose just about 20 hp, C4s almost twice that, C6s three times that. A Poweglide's loss is somewhere between a manual trans and a C4, that's one of the reasons they're so popular for drag racers. A Ford 9" is a power hog compared to an 8" or even a 12-bolt.
Most of it has to do with the angle of where the pinion gear intersects with the ring gear, it's very low towards the bottom of the ring gear. Other rears have the gears meet higher up where it's more efficient because the gear teeth can be cut straighter, and there is less gear surface area rubbing together to cause friction. But the 9" low pinion (more gear surface area meshing) is one of the reasons it's so strong. You trade off efficiency for strength.
