427 FE vs 351w, advantages?

[Jerry Clayton]

As for crank weights---today I balanced a couple of engines--altho both were chev they are representative of what we been talking about---the sbc with a 3.75 stroke(1/4) weighted 47 1/2 lbs--the bbc 4 .250 strke weighed 62 lbs---these are both fairly lite wt internally balanced cranks so the counter balance weight is on the crank, not flywheel or frt dampner

[madmaxx]

With a difference of 14.5lb (alot of ounces) it would be impossible for the dumptruck big block to rev as fast as the small block. One truck engine will be linear in acceleration where the small block will be exponential. It comes down to performance or looks. A 500hp small block will beat any 500hp or larger big block in a blast from zero to 60. The small block will spool up faster and more than 500hp in a cobra cannot be effectively put to the pavement.

Originally Posted by Jerry Clayton

As for crank weights---today I balanced a couple of engines--altho both were chev they are representative of what we been talking about---the sbc with a 3.75 stroke(1/4) weighted 47 1/2 lbs--the bbc 4 .250 strke weighed 62 lbs---these are both fairly lite wt internally balanced cranks so the counter balance weight is on the crank, not flywheel or frt dampner

[RodKnock]

Originally Posted by madmaxx

The small block will spool up faster and more than 500hp in a cobra cannot be effectively put to the pavement.

There's a guy named Blitz that may want to argue that point.

Assuming you think 10.75 seconds for a 1/4 mile is effective.

[blykins]

Originally Posted by madmaxx

With a difference of 14.5lb (alot of ounces) it would be impossible for the dumptruck big block to rev as fast as the small block. One truck engine will be linear in acceleration where the small block will be exponential. It comes down to performance or looks. A 500hp small block will beat any 500hp or larger big block in a blast from zero to 60. The small block will spool up faster and more than 500hp in a cobra cannot be effectively put to the pavement.

Just to be fair, I have to say a few things here....

If you've never heard a 470-480ci BBC spinning at 8000, then it's something you have to hear once. I see a lot of pulling motors on the dyno that would probably out-rev any small block on this forum. It's not impossible...

Also, you have to watch what generalities you use about 500hp small blocks beating 500hp big blocks because that's not entirely true. How quickly you rev doesn't win races. I'd rather have a 500hp 408 than a 500hp 347. I'd also rather have a 500hp 482 than a 500hp 408. I've been in them all....there's no comparison.

Rod makes a very valid point.....Blitz's "slow revving" big block on less than desired tires put it all over that quick revving Ferrari.....and didn't have trouble with traction at 700 hp.

[rodneym]

Maybe some of you experts can answer:

Assuming you have a SB and BB with the same redline, I can see how the SB would spool faster in nuetral, but what about under load? Wouldn't the mass of the BB then help?

[bobcowan]

Originally Posted by Jerry Clayton

As for crank weights---today I balanced a couple of engines--

That means the BB crank is 32% heavier than a SB crank. The rest of the rotating and reciprocating assembly is probably a lot closer in weight. But still, you can expect the entire assembly to around 30% heavier. That's a lot. A tire and wheel assembly that's 5# lighter is a real boon to the racer. So why wouldn't a similar weight savings inside the engine provide a similar benifit?

I'm not arguing with anyone, I'm asking the question. I sure would like to see real data on that sort of thing. Not only HP and torque on an rpm scale, but also on a time scale. I think that would be interesting.

Originally Posted by madmaxx

With a difference of 14.5lb (alot of ounces) it would be impossible for the dumptruck big block to rev as fast as the small block. One truck engine will be linear in acceleration where the small block will be exponential. It comes down to performance or looks. A 500hp small block will beat any 500hp or larger big block in a blast from zero to 60. The small block will spool up faster and more than 500hp in a cobra cannot be effectively put to the pavement.

I wouldn't think it would be imposible, but I think it would be difficult. I think (but could be wrong) that if you built similar Windser and FE engines (compression, head specs, cam, etc) and raced them, the SB would win. The rotating assembly is lighter, and most likely quicker. The BB is heavier all around, and weight is the enemy of any race car.

And, yes, you can put more than 500hp to the ground effectivly. It's been done many times. It's just not easy.

Besides, who really cares about HP anyway? It's torque and area under the curve that matters. The slightly longer stroke of the FE may give that engine an advantage.