I did a 383 before I really understood the difference and now am looking to do the 402 - so I'd have to agree. Luckily, I used AFR heads that will work with the Big Block when I go that route :>)

 

I think you guys are missing the point. It's an aluminum 5.3 with stock sleeves. I don't think a 4" bore on stock sleeves is a good idea. You're talking about boring 220 thousandths

 

What I think they are saying, if you are going to spend that much money, dump the 5.3 and build a 402 from a 6.0L. Same money, but more hp/tq.

Thanks.

 

and 100 more pounds on the nose

 

What do you mean 100 more pounds on the nose?

 

If it was an iron block vs aluminum.

 

If all you want is 359" just buy a good used 6.0L LQ4 or LQ9 and not have to worry with crank, rods, pistons.

Otherwise, if you are looking for MORE, it is better to start with a 4.00" block ANYWAY. A 370 uses stock crank so it is a lot cheaper.

If you are just itching to buy a crank, build a 402, or 408. They all cost the same, and a bigger bore will almost always pay better results with no valve shrouding issues.

 

Few people will ever notice the extra weight on the nose. It is closer to 80, but no matter. The better power will more than make up for it.

 

all the numbers ive seen put it around 106# difference.
that is significant for anyone concerned with performance.

 

Fair enough. But I did not notice anymore weight on my Firebird. Perhaps if I was an autocross fan I would. But even with the iron block, and Hard Blok in the bottom half of the water jackets, my car would raise the nose much quicker than it did with the Al 5.7.

Would seem to me it would be even less noticeable in a truck. But if he is trying to make it 'handle' I can see your point.