You'll lose abotu .1, but you're hitting the nail on the head with the weight transfer, adding 100 lbs to te nose pretty much negates all the front end weight loss that people do to their drag cars. I know there's tons of guys that will tell you it doesn't matter, but when you're trying to et a car to 10.50 or better on motor with only 500 rw and a car that still weigh's 3600 with driver, it's alot bigger deal then most realize.

 

JL, it seems that most of the people I have done these iron engines for go faster after going to the iron blocks. I have never seen people slow down in drag racing so far. I'll find a way to weigh these damn blocks soon as they are slightly over my weight scale but I don't think there is 100 pounds either as I said. I think when we weighed them at Fed Ex it seemed like only 70 pounds but I could be wrong.

 

If it's only 70 lbs, that's a good thign IMO. Someday, if I feel the alum that I'[m going with is a problem, I'll swap to an iron... it's not like it's a 3000 block that I'm buying, and the iron blocks aren't so expensive that they are out of my reach either... just going alum for the weight reasons, when you're goals are pretty much gonna require "beating" the slide rule, weight is a factor.

 

JL, I am going to find out for all of us what the real weight difference is but who knows it may be 100 but I don't think it is. My only problem with the aluminum stock blocks is the weak cylinders but they still work pretty good in reality just not as nice as the iron blocks do. The weird thing is even though we are not running Pro Stock (also where you CAN run aluminum but no one does due to power differences) the iron block cars really do seem to go a little faster even though they are heavier by a slight amount.

This could also be the result of the other stuff people usually do when going to an iron block deal though so I don't have any really scientific proof at all. Also the aluminum block always shows more cap walk than the iron ones do although as you said I haven't seen the aluminum blocks blow up or anything.

 

You're right, the iron block cars are running strong #'s, and I think you are right, most of them are on te very radical side of the spectrum as well, probably why they are putting up some of the biggest #'s. However, you can look at harlan's car, he was running in the 8's a while before alot of the other guys, and was on a stock ls1 block and crank, and did not suffer a failure in either department... so even if the main's move some, adn teh sleeves aren't as strong, is it enough to really matter? I guess, in a perfect world, all tings being equal, the exact same car, same weather track, same traction, same power adder ( wether it be boost, nitrous, big n/a whatever ) if there was a way to do that, and only change the block in a car, and the weight as well from the block, would it go faster or slower? Who knows.


As for prostock.... I understand that they can run alum, but have weight requirments for total car weight, and don't have the concern of the blcok being too heavy, i think that's one reason they stick with the iron, if it was a weight disadvantage to run the iron over an alum block and they could go faster with the alum due to the weight factor only, they would all have alum in the car, weaker block or not.

I like both setup's myself, it's just that I came across an offer that I felt was too good to pass up, and will be doing alum. When I tear the motor down in a couple years to redo the bearings and the rings, if there's any evidence that the block is somethign to be concerned with, I'll definately look into an iron replacment. But, like I said, with the power I'm trying to make, I doubt that I'm pushing it hard enough to have an issue. I don't think that 500 rwhp on motor, and a 150 shot down the road are gonna be enough to truly test the strenth of the block itself, and the components that are going into it are as good as you can really get, much better then what I could even have afforded to do had I not happen across the deal that I have. that being said, I feel confident that what's being built to go in my car will be more then adequate to meet my goals. now, if I decided to hook up a 3 stage nitrous system, and each stage was a 150 hit, then I think I would be looking at a differnet situation, but that's way more then I will need to accomplish my goals. I think that even a 150 hit may be more then enough, I was looking to get to about 10 flat with a realtivly heavy car on a 150 hit, at this point, I'm probably gonna be looking at better then 10.80 on motor alone, and I'm sure that a 150 hit would be enough to go faster then 10.0

 

JL,

I'm not busting your ***** or anything so don't take it like that. You'll probably do great with what you have. I am also sure that Harlan's block is probably almost toast by now with some pretty extreme cap walk. I've seen several like that. Some of these guys don't have as many passes as you might think on these oem blocks and sometimes things get broken and not reported too. I have no idea in his actual case but I have seen a lot of "behind the scenes" stuff! You can run big dowels and the aluminum block will hold together better down there but maybe 5 percent of aluminum race stuff is converted like that.

 

I may just stick to my LT1, hate all you want.

 

Erik, I know you're not busting.. I guess I'm trying to justify my reason for going alum, although ther's really no need. As for the bigger dowels and billet main cap

I am sure there's lots of failures out there that people don't know about. I know of an alum block cracking, where a small line from the casting process was, apparently it created a weak spot, and under heavy abuse, it ended up cracking and leaking coolant at that spot. Those kinds of things do happen, and I'm sure that we never hear about 1/2 of them on here.


NOthing wrong with lt1's either license, there's plenty of those that are quick too.

 

One quick question, anyone that can answer please do so.
Are the LSx main's design stronger or not than Gen1+Gen2 design, I mean is it debateable..... or is it slightly better......... or is it weaker...or is it leaps and bounds above old school......or perhaps it remains to be proven but track record results are varying right now?

I can understand the aluminum blocks structural integrity failures, even when so so pushed or to not offend when pushed to extremes, but are there design questions along the bottom end's strength, play, or cap walk that would apply to both iron and aluminum LS blocks? becuz cap walk represents a casting design issue, not necessarily material used. Don't they use iron caps even on the aluminum bottoms?

 

Look guys if it the weight difference your concerned about, just simply remove the spare tire and jack along with the t-tops LOL...

 

I wish there were Iron heads for these engines. I'm tired of melting all this Aluminum.
I guess for us non pros their has to be a learning curve, but it sure can get expensive.
I just melted my 422 Aluminum Block and Head. I melted my stock engine a few years ago. I may try an Iron Block this time around.

 

and how much nitrous are you trying to spray? I'm guessing ALOT if you are actually melting the alum.

 

Yes,I'm spraying a little. I don't know how much, but I'm traping 147 mph in the 1/4 mile.

 

That's odd... I mean I've heard of people doing that, but it's mostly with cars that aren't running the right fuel, or the tune is a mile off.. somethign.

 

I chose to go with the 383 aluminum because I did not want any issues with the extra weight over the nose...it's a daily driven street car. I just wanted a little more power, so I wasn't worried about .1 here or there in the 1/4...

 

408 here, but I may be biased.

 

It depends on your goals and your budget, most guys are not concerned with every last tenth and want a nice street car. In a street car that sees the drag strip a few times a year I'd be tempted to go Iron if the motor is that much cheaper.

I want to drop a lq9 in my Chevelle as it is cheaper than a ls1/ls2 and can still make the power. It will also weigh less than a 350 and much less than the iron block and head 396 sitting in it now.

Also I want to build a track car for road courses, that car would have an aluminum motor in it.

 

LS2 402. $4,100 from SDPC. 383 will not be much cheaper. I think TSP had the 408 iron block for $3,400 or $3,600, Can't remember.

 

For those of you who like your ls2. Arent parts like headers etc more expensive? I Think im just going to go with a forged 347 ls1. I thought about a turbo setup but I dont believe I want to go that route. I could fab my own turbo kit with my tools I own and such but Its so hard to tune . I believe im just going to do mild to high cam swap with some ls6 heads. And a supreme fuel syste mand a LARGE shot of nitrous sitting on top of a nice transmisiion> Any tips suggestions? Not trying to steal the thread just curious maybe he would like to go this route if you guys had opinions?

 

that sounds good for the street/strip...and wont BREAK THE BANK!