[jim_howard_pdx]

No

a 302 crank and a 351 crank have different main journal diameters. The 351 uses a 3 inch main journal which puts enough meat on the crank to support 1000 hp or so.

What you do is offset grind the 351 Windsor crank, usually a forged crank, to get down to the destroked point where you can add the length back to the rod. On a stock crank, I usually go for a 332 cub inch engine. With a custom forged crank blank, I can get it down to a 306 or 312 and hit the 2.2 rod ratio I desire.

On a 351 piston, it is relatively easy to get a forged piston with a .5 inch taller pin location. Then take a quarter inch off the 351's stroke, and you end up with a 6.695 rod. I just bump the rod to 6.7 iches and measure to maintain a minimum .39 quench on the deck. Some modern race engines are building zero deck engines, so the piston actually pokes up through the head gasket space, but this is very dangerous, and I do not recommend it for us common folk.

With any rod, over time the rod bearing cap will elongate into an oval, and when you put that .001 inches back into a zero deck height race engine, you get catastrophic failure.

I believe a stock 351 crank, nodular iron can be cut to 3.2 safely. Perhaps lower, but I really like 332 engines, so this is where I destroke a nodular cast iron crank. Then go with the longest rod, shortest piston you can fit. 1.98 rod ratios are easy, 2.05 to 2.1 come at a price, the oil control ring land will be machined in the pin's boss, so you lose oil control. Ok with racing, not as ok on a street engine.

My extra secret to you is this. At 5,000 rpm the spark plug is firing some 30-36 degrees before top dead center, so as the mixture is compressing, the spark creates preignition, a kernal that must get the air fuel mixture to burn as fully and completely as possible. With a long rod, the piston is higher in the bore at 36 degrees btc. See why you build more torque? You have more cylinder pressure, greater quench, and less chance for detonation because the mixture has been compressed more at 2.2 than at 1.5.

Plus the longer rod accelerates the piston faster up the bore during the compression stroke. This creates more mixing of the air and fuel in the cylinder. Then at the top of the stroke, the long rod slows down and "dwells" the piston LONGER than those short ratio engines.

I should have told Ultra flow this in my response, but I wanted someone to say WHY would your 428's 1.88 rod ratio almost double the torque of that 350 small block engine with only 78 more cubic inches????

This is the reason. When the spark ignites, the piston is higher, quench is tighter, cylinder pressure is higher and THEN we get the cherry on top.

The cherry is that the piston "dwells" longer at tdc than the short rod ratio engines. So the fuel is burning and the piston is parked there as cylinder pressure goes astronomical. The pressure exerts far move leverage against the piston and crank.

See why a NOS or charged engine would put out 1700 horsepower with 420 cubic inches (like Eric 4 Nitrous's Missle Car!) Only his rod ratio is short, so he has to use three stages of NOS to compensate!!!

And the best part is yet to come. Now as the piston falls away during the power stroke, more cylinder pressure is being exerted BUT the long rod engine pulls the piston away slower at top dead center, then very quickly as you move to center bore. Since your pistons are firing 45 degrees apart, this means that the extra torque is multiplied by a factor of 8. So if you are building 10% more torque in one cylinder, it gives you 80% more torque at the flywheel or pressure plate.

You get all this for FREE, other than the cost of admission.

You use less fuel to get more torque. You get a lot more torque at every rpm range. You get mind altering results with NOS, Turbos, or Super Chargers, and you get less chance of detonation to boot.

That is why the 302 Boss ran 224 mph at Bonneville. It had a 351 Windsor block, and it had a custom forged crank that let us offset grind to a 3 inch stroke. Titanium rods and pistons kept the reciprocating energy low. Compression ran 11.5 to 1 and for the bonneville run, my Pantera buddy ran gasoline only. Later he added direct port injected NOS, and eventually went to dual turbos. I helped him with the destroked block, piston shape, head work and bolting everything together. I also helped him with the direct port NOS injection.

I am glad he had some money, cause it cost 100 grand to build this race car. 25 grand in the engine alone.

So if anyone tells you the jury is out on whether long rods are better than extra displacement tell them both sides are right. BOTH methods work. I can build a 10 second car either way. But the long rod engine will have a broader and taller torque curve, it will consume less fuel to build the target horsepower you need, and it will run without detonation. It can tolerate more advance and can take it sooner also adding to the torque levels of your engine.

So now you know the physics. Next time you build an engine, set about to maximize that rod ratio. You will be happy that you did. 1.9 is the minimum rod ratio I would want to run on any of my race engines. Next time I rebuild by 358, or build a new engine, I plan on building a 2.2 ratio engine. It may be a 460 block, or it may be a Windsor. I just want something to play with that when boosted by a Vortec or Novi blower will make 700-800 horsepower, idle like stock, get 16-18 miles per gallon, and run like a triple crown winner.

You can have your cake and eat it too, if you take the time to make it a long rod engine.