Just like the title says. I'm trying to decide if I want to go Al or Fe.

Thanks,
Chris

 

Chris,

Just Installed my SDRE 427 Iron Block, I have noticed no difference in handling as of yet. Except the front end being just a tad lower, so now you have to watch a little closer to the road bumps or RR crossings thats about it.

 

:cool: :steering: With iron blocks you are adding a lot more weight! For the $$$ you are better off with al. :yesnod: :yesnod: :yesnod: :cheers:

 

But as far as the money is concerned you're talking about $600 for an iron block and around $3000 for a darton sleeved aluminum block. I realize it's around 100lbs more for iron, but I was wondering how adversely the handling would be changed with that added weight.

 

Good Post! I don't corner my Z51 Vette with Kumhos beyond the 90% level anyway. So does it make the car feel like a front heavy slug? I guess I could pile some sand bags in the front end and find out!

 

I HAVE A 421 IRON BLOCK HYD ROLLER THAT JUST DYNO'D AT 502 AT THE REAR WHEELS. I GET 30 MPG ON THE HIGHWAY, DRIVES JUST LIKE IT DID BEFORE, WITH ABSOLUTELY NO SIDE AFFECTS. I GUESS IF I WERE RUNNING THE ROLEX 2 HOURS, I MIGHT NOTICE A LITTLE, BUT I PUSH OFF RAMPS AS HARD AS ANY ONE TO NO PROBLEM. THIS BY THE WAY WAS WITH A STOCK UNTOUCHED LS6 INTAKE, CANT WAIT TO SEE WHAT ONE OF THESE NEW INTAKES WIL DO.

 

I guess it depends what you are going to do with the car. Street car or road race? Even a 1/4 mile car would not want the 100 lb. extra especially in the front. You could put heavier springs but then that is more money again.

 

From what I understand the for every additional 100lbs it's an extra tenth in the 1/4, but I imagine this difference can be offset by the ability to push the engine harder due to the stronger nature of the iron block. At least that was the assumption I've been going on. Really the biggest determining factors are the weight increase, which from what I can see so far doesn't seem to be a problem, the strength differences between the two, and largely the price difference. Also the Al block can be bored considerably larger with the Darton sleeves and in the event of a failure the sleeves can be replaced. I've also read rumors of overheating problems with the iron, but I haven't heard any definite stories about this. It's really a difficult decision. Luckily it's not something I have to figure out immediately, as I don't even have a Vette to put an engine in anyway, but I'd like to figure it out and build it beforehand so I can drop it in as soon as I have a car. So don't mind my endless question-asking, just trying to figure it out so I don't make a mistake when the time comes.

Thanks again,
Chris

 

100 lbs on the front is a disaster. It will cause increased push (skidding) in sharp corners that you would get in a low speed autocross and the increased push would really change the balance of the car in high speed road course turns where you wouldn't be able to get on the throttle as quickly. People are concerned about a lot less weight than that. GM even put a thinner windshield in the Z06 to keep the weight down. Not only do you have to accelerate that weight but you have to get it around the corner and you have to stop it.

If you are into drag racing go for it. But if you do it then you decrease any enjoyment you can get out of running a DE which is a hell of a lot more fun than a 12 second run down a drag strip.
Bill


[Modified by Bill Dearborn, 11:57 PM 9/19/2003]

 

My most recent motor was a 427 iron motor and the extra weight on my 98 vert used as a street car weekend warrior did not bother me at all and the one big difference is how the front end was lower b/c of extra weight. Well i abandoned that motor for other reasons and my brand new C5R block MTI 427 Ls6 headed engine arrives home at 7:00 am sat. morning (9-20) and i will take the 100 less lbs in the front end no problem! CAN YOU TELL THAT I AM PUMPED UP!!!!! :party: :hurray: :auto: :grouphug: :steering:

 

I would like the car to be able to do pretty much whatever I feel like, whether it be auto-x or drag racing. Does anyone know how much stronger the iron block is than the aluminum, because this would really sway the decision one way or the other.

 

I take it you are going to be going with more cubes over stock 346 displacement? If staying 346 then obviously stick with a stock LS1 or better yet LS6 alum. block.

If your going for bigger cubes 383+ then i would suggest if $ is not a big consideration for you, the best of all worlds, that being the C5r racing block which makes 427 cubes the EXACT SAME WAY that GM Racing gets 427 in the C5R race car when matched with 4.00 crank.

If this is out of your price range ($6,300 for bare block only) then go with an iron block bored 4.030 matched with a 4.00 crank for 408 beatiful cubes. This would be 100% more durable than a resleeved alum block which are know for dropping sleeves every know and then and that would REALLY SUCK!

Going 4.030 on an ironblock would leave plenty of durability and strength to spray the **** out of it or go with major forced inductoin and still have meat left over in the cyilinder walls for a rebuild, etc.

Whatever you do, don't go with a CALLIES crank (stick with LUNATI) and don't go over a stroke of 4.125 as THAT IS TOO MUCH STROKE for an LS1 ironblock motor (TRUST ME, i learned the hard way on that one) and in my opinion too much stroke for any LSX motor! :yesnod:

GOOD LUCK and do you homework well! :cheers:


[Modified by MTI 427 Roadster, 10:55 PM 9/20/2003]

 

THe C5-R block is way out of my price range. If I went aluminum I would go with Darton sleeves so there is no issue of dropped sleeves and most likely a bore of 4.100" and a stroke of 4" which would give me a 422 and in theory plenty of meat left in the cylinder walls. Iron I would prob look somewhere around 410CID of so as I realize that the max it can be bored is .060" over leaving no room for rebuilds. Either way I'd be going with a Lunati crank and rods.

Oh, and I'm assuming you meant don't go over a stoker of 4.125" not bore, as the iron can't be taken out that far. I wasn't planning on going more than 4" on the stroke anyway. All the reading I've been doing has taught me that excessive piston velocity = bad.

Chris


[Modified by DngrZne, 9:07 PM 9/20/2003]

 

Yes, i certainly meant don't go over more that 4.00 for your crank/stroke. The bigger the bore the better and of course achieving the most cubes with the biggest bore and smaller stroke is the way to go on the LS1 motors (i speak from experience as my iron 427 motor did not work out for me).


The only problem with th DARTON sleeves that i have read about are they are not quite perfected yet by the major tuners such as LINGENFELTER, etc. who has them on their website but has not released one yet as they are still R&Ding them, etc. as they are not proven yet in real world applications. However, i have heard of several persons offering a darton sleeved LS1 resleeved alum. block which allegedly should be good to go but from what i have seen, these are not quite battle tested yet and are still in their infancy regardng longevity and reliabilty, etc. I say stay with an iron block (cheaper also by about $1500.00) and if you stay N/A you can get 414 cubes with 4.060 overbore and 4.00 crank but DEFINTITELY get the block SONIC TESTED as i have read that many new iron blocks can't even safely be bored out to .060 over as not enuff cylinder wall thickness.

BEST OF LUCK and if you go with a darton may as well go with a 4.125 bore for classic chevy 427 cubes (5 extra over 422) with the 4.00 inch LUNATI CRANK!


[Modified by MTI 427 Roadster, 11:04 PM 9/20/2003]

 

The iron block is only about 80 lbs more. Its not that big a deal...the difference between a full tank and near empty tank of gas is over 125 lbs. So with your reasoning, a near empty tank would shift the balance forward and give disasterous results....not the case. Put your battery in the back and get a carbon hood....problem solved. :cheers:


[Modified by HIGHRPM, 10:13 PM 9/20/2003]

 

Very true...I believe the exact difference of the two blocks is 92lbs after doing some research. The addition of a roll cage will also shift the balance further back. I suppose in the event I wanted to go to an aluminum block at a later date the cost would be relatively small anyway, as the crank and rods would be reusable and the iron block would have been a small cost relative to the whole engine. A 408 or 410 would be a good size to go and then I could throw a 200 shot or perhaps even more on top of it safely.

Thanks for all the input,
Chris

 

A 408 or 410 would be a good size to go and then I could throw a 200 shot or perhaps even more on top of it safely.

Thanks for all the input,


NOW your TALKIN BROTHER!
:cheers: :cheers: :cheers: Best of luck and glad to HELP!!!! :steering: :chevy :smash: :cheers: :cool:


:seeya

 

ARE has prooven that their re-sleeved blocks can hold over 1000HP.
I don't see there being an issue with dropped sleeves anymore. Definatly the way to go :yesnod: IMO sould be just as good as the C5R block for your needs.

 

What about MTI's resleeved Aluminum block, this is what I'm thinking about buying http://www.motorsporttech.com/c5_engine02.asp :cheers:

 

People are telling me for a big shot of nitrous the iron block is better...maybe the nitrous is harder on the block than just generating the HP N/A or FI?