View Full Version : Alloy block vs Iron block

03-29-2008, 12:16 AM
I was just wondering; apart from the weight factor is there an advantage to using an alloy block over an iron block?
Also, for my 615ci twin turbo application would an alloy block be better? The weight loss would be very nice to have but would it suffer from block flex?

Pro's & cons anyone?

03-29-2008, 04:37 AM
Cast will last longer and make more HP. Do you have a weight rule in the class you're running in? generally you can make 30-50 hp with cast over the aluminum. 30 being pretty much an even trade off for the weight. 40 starting to be worth the extra weight. Ever notice that the prostock guys aren't running aluminum blocks? Thats mainly cause their making more HP with the cast iron Blocks. Just my opinion.

Later, Don :cool:


03-29-2008, 09:57 AM
I sort of had a feeling that a cast block would be better for my application. I have no weight limit/restriction; along with no cubic inch limit or any restriction for that matter. I will be in a class with a minimum weight & that's it.

03-29-2008, 12:38 PM
Sent you a pm Turbo. Click on the Private message at the top right of this page.


Awesome Bill
03-31-2008, 10:36 AM
I would run the Billet Dart block hands down. You don't have to worry about squeaking out 20-40 hp naturally aspirated. That would be silly. with 40 lbs of boost and a freezer sitting beside you, you will need that weight off the front end more than what power you could make. The billet block is pricey but it just as strong as the steel block. I would not use a casted block if your making over 2000 hp. Spend the bucks and get the Dart billet piece. When you can get the car to work well with all that 150 lbs off the nose you will be glad. Ask Don Burton about nose weight. He is one of the best 60 fters. out there and you will kill your application with all that nose weight. Not just the block but think of your turbos way out there and everything else hung on the front end. That is a ton of nose weight. Its really not that much more between the 2 engines. Maybe $6000 total but you have an engine that is worth a ton more and in the class your running, its run what cha brung!

The weight difference between pro stock short block steel verses a standard tall deck aluminum is only 40 lbs at most. They are required to use a steel block and it is way shorter and lighter thatn what you think. I have one, its a work of art. So don't be silly with the money your going to spend. YOU HAVE TO GET IT DOWN THE TRACK. Nose weight will have an affect. Most likely guys kill power to use it. Sounds silly but why have the power and can't use it? It does no good. jmo

03-31-2008, 11:38 AM
I just looked at the billet block section on the Dart site but it only mentions 5.0" & 5.2" bore spacing motors; to step up to a big bore spacing motor is out of the question for me, I simply cant afford all the specialised parts associated with one of these.
I also just found out that the BRT 2000 wont handle the power so it's the glide I guess; well, until it starts becoming the weak link anyway.

04-01-2008, 04:08 AM
odd that Prostock guys add a lil ballast up front on their cars. But I think Dart can make you about anything you want. Might be speaking out of turn there though. More then likely theres a good reason that the fuel guys are running aluminum blocks.

Later, Don


Awesome Bill
04-01-2008, 09:58 AM
There are many different named glides but our Monster Glide will handle safely 2500hp and up to 3000 with a spragless converter. The Dart Billet Block is what you tell them you want. They will build the 4.840 block just as fast as a 5.0 or 5.2. If your going to run with the big dawgs and be competitive, I did not say win, your going to have to step up. I really don't care about a 5-10 lb ballist up front and you are not running pro stock. This is a totally different combination and should not be used to confuse you about chassis tuning. That is an acceptable weight for their stuf. It is so light in the ont end it is ridiculous to start with. When your going to run all the stuff that comes just with the twin turbos, you will add at the very least 200 more lbs to the front end. I know, I have a single 106 and it alone is as much as a steel head. Put 2 of them up there and you got a steel block hangling way out front. You should also think about a mechanical fuel pump and leave those crazy electric pumps. Anyway, if you can't get it up for the aluminum block, you have to do what you have to do.

Of course there is the option of the other blocks, DART, Donovon, and Brodix along with a few others. We do have a pro mod guy making around 2500 with a DART casted aluminum block. He runs very well and is blown with a bad blower set up. I am sure Donovon or Brodix stuff is comparable. So I do not recommend it but I also would not want you to go broke trying to get this off the ground either. Steel is cheap, but is very heavy. If you can not tune a chassis, then you won't for sure tune it with the steel block and twins out front. Your nose weight will kill you. If you do not believe me, go ask some people running those things. You will get pretty much the same across the board, keep the weight to a minimum on the front end.

As far as fuel guys, you would get a little tired of yanking a short block out that weight 200 lbs more every round and when they windowed it, they just unbolt and bolt back the a new section. Its about time, repair and availability with those guys. You are not even in their class when it comes to what they have to do nor would you want to.

Using a very small amount of ballist to tune a chassis is needed. I even have to add 5lbs to my dragster when it becomes a Top Dragster or it will come right over. So tuning is one thing but a putting 200 more lbs of nose weight out there is crazy. hthelps