How critical are forged internals?

[BullittStangV8]

I've been researching allot latly about stroker kits for 351 based motors. My goal eventually is to get a stroked 351 in a 65 coupe. I see some people talking about simply getting 393 cranks, and throwing in 5.0 pistons on top, with a set of rods. (Seems real cheap) I want my motor to make ALLOT of hp, as the car will be mostly a drag car with minimal street duty. So my question is this: If I want the car to be able to run on 93 octane, but make some very good HP numbers, how neccessary is a forged crank, rods, and pistons? Im looking for around 450 FWHP (or more). And yes, I know other parts will need to be beefed up like the rear, suspension, trans, etc. but right now im simply asking about making power and longevity in for a stroker motor.
Discuss.

 

[NasaGT]

I'm going to be rebuilding my 351 in the near future as well. From what I've read, if you are staying N/A then you don't need forged internals. You definately don't need a forged crank for that horespower level. Alot of people recommend forged rods and pistons just for peace of mind though.

 

[LMan]

For your uses, forged pistons - good idea

forged crank - not needed

 

[thehueypilot]

I'm running forged pistons and rods but a cast crank and it held togther last season. The pistons are melded a little from trying to run 93 octane while advancing the timing until it rattles then backing off slightly. I recommend forged pistons and rods as a minumum.

 

[kmterrill]

Another vote for Forged Rods and Pistons.

 

[gzminiz]

i am doing all forged internals. To me it gives piece of mind. It might not need it but i figured I might as well the extra few hundred for a forged internals and make the engine as bullet proof as possible. At a minimum i would due pistons and probably rods.

I think of it this way, when it is all together are you going to put crappy oil in it or the best possible to protect it? Sure it isn't on the same cost scale but over the years it will be.

 

[10secgoal]

I wouldn't get anthing rated too far over the block. Putting forged rods in a 5.0,kinda pointless if you have a stock block. Depends also on how high you wanna spin. A good I beam should be able to hold up to 450fwhp pretty easily.

 

[Great68]

For stock blocks, Fully forged cranks are a waste of money. I have not read or heard of one instance where a cast crank let go before a stock block.

Forged pistons and rods are a good idea though, and my next shortblock will be getting them.

 

[65ShelbyClone]

Aren't all rods forged? Even stock ones? Not that I don't recommend an upgrade, but i'm almost positive they are all forged.

Yes, factory Ford forged steel goodness. Chevy is the one that used "powdered metal" rods.

I personally would keep the stock 351W rods and get some forged 5.0 pistons and a cast 393 crank. If you keep it under 6500, the rods shouldn't be an issue. If you gotta have 'em, then maybe some aftermarket steel I-beams, but nothing crazy. I'd be disappointed if I build a 393 that didn't make 450hp, actually. That should reasonably doable without even a stroker.

 

[mustangdave]

I killed a stock 351W because of a bad rod. They are very wimpy. It took out two cylinder walls, two pistons, the crank, and a chunk out of the block. I believe upgraded rods are a no-brainer for the price.

 

[timeless2]

If you are putting that much time and effort into a build-up, why not do it right the first time? The variance in price will save you time and money in the long run, should something bad happen.

 

[BullittStangV8]

thanks for the replies so far guys. What do you think about compression ratio? The motor has to run of 93 or less octane. Also, the motor would be N/A, with the possibility of a small shot eventually way down the road.

 

[thehueypilot]

10.5 comp ratio or less.

 

[SoCalCruising]

Actually, a cast crank is stiffer than a forged crank, but will also tolerate less deflection (i.e., more brittle). What makes a forged crank a good idea is high HP, or high RPM, or both, obviously. Either will tend to distort the crank. A forged crank will tolerate more distortion before breaking. However, I agree that a forged crank is not required at your power level. I would, however, never scrimp on the balancing of the rotating assy and the purchase of a quality harmonic damper. I believe that these two elements are key to the longevity of a cast crank and stock block. If you want longevity, get the longest rod and shortest piston you can find at a reasonable price. Try Scat.

 

[D.Hearne]

Ford's using PM rods in the Mod motors now. All pushrod Ford V8's had forged rods, just some were better than others. Forged pistons and rods? Yea. Forged crank? Not necessary unless you're REALLY gonna hammer it.