As the time for dyno tuning gets closer and closer, I need to start thinking about how much Nitrous I want to add to the fun factor without cracking the block. I don't care to be the fastest car on the track - consistancy and repeatability is what I'm looking for. I don't want to have to tear the engine down ever month, yet I don't want to be a slug either. In your research or experience, on average, how much Rear Wheel horsepower can a late model 5.0 withstand? Related info: Block is now a 347 and all forged components (supposedly, the block is now the weakest link). It has the lower main girdle (for what that's worth). C4 Tranny. I'm guessing my engine will put out somewhere around 375 FWHP on motor. The engine is Mass Air E.F.I. A single Nitrous Express "Shark" nozzle will be used inline of the cold air intake. If providing FWHP, what factor would do you use to estimate RWHP? Thanks, guys.
Some guys can make 750 HP on a factory 5.0 block. Others can't make 400 and they crack 'em. So who really knows what the limit is?
Where it was cast, year it was cast, and luck. Also assembly technique and proceedures. I have heard to never exceed 600HP on the best of blocks, but many have gone further then that. And as Mavman said, they can crack at 400 too. What will help? Heavy webbed castings like in the Mexican block are preferred. I'm currently working on a 1969 dated Mexican block and they are quite different from the run of the mill 289 or 302 block. Also, one of my engine building books author, George Reid, says to stay away from all blocks made from 1975 to 1984 because of poor quality iron used. Castings became much stronger with the intro of the roller motors. Luck being 3rd, sometimes things just break no matter how hard you try to prevent it. All the forged components really help, as well as using high quality gaskets and bolts like ARP's. I don't know a whole lot about NOX, but it will stress everything, even on a small shot. Eric J
I'm thinking about staying around 500 FWHP to be safe (and practical). But then there'll be that one time when some Cheby guy is gonna make me wanna blow him off the track and I'll wind up using the "Pill it 'till you Kill it" method anyway. I know me. I'm setting here studying the jet combo to make a 250 shot.
The ricers wouldn't run me if I didn't have 'Front Wheel' drive so I converted. I'm using an Oldsmobile Toronado Front Wheel drive axle. (and to those who might not know yet, yes, "FWHP" is "Fly Wheel" h.p. There's a (debateable X factor of hp loss by the time it reaches the rear wheels (RWHP) due to friction and energy loss used to turn all the rotating components between the motor and rear wheels) ------------------------ Okay, 600 FWHP it is! (and I'll have a freshly zero decked/line-honed, modified 347 block wrapped up in the garage waiting for the internals when the old block does crack).
I read in one of the old (How to rebuild your Ford Small Blocks) don't remember which one though, I read that Ford added more iron to the webbing and other areas of the Mexican blocks to make up for the weaker iron and lower quality control of the factories in Mexico. Is there any truth to this? clint
As many answers are with a Ford - maybe. Some authors claim a higher nickel content and others say it's not higher. But they most definately are a beefier block with massive main bearing caps and thicker webbing. Most likely because these blocks were primarily put into heavy duty applications, like trucks and vans.
hey rick, the 5.0 will handle anything you throw at it. the question is for how long???? the mexican blocks are said to have a higher nickel content. i've got one coming next week. got the block and crank for $150, supposedly just bored .040 and crank polished. saw one recently on ebay for $500. they are getting rarer.
Fwiw: I don't know for a fact, but I have read specs that say the 5.0 blocks are lightened so much that the main caps are hollow... not to mention very thin castings. That in itself scares me away from roller blocks.
Rick another thing to consider a couple weeks ago on Hot Rod TV on their hot parts they showed a block girdle for the 5.0 that set under the intake, one in the front one in the rear it spaned across the valley from side to side and tied it together......just a thought
