i know this question has probably been asked a million times. i tried a search but didn't get all the answers i need. im am getting ready to build a street stroker for my 02 m6 z28 and i am trying to decide if i should go with iron or aluminum. the car is my daily driver. it will get driven hard every day, go on occasional road trips, and go to the dragstrip a few times each summer. i will probably put a 150 or 200 wet nitrous shot on it. i know that the alum will cost me more but that is not what im worried about.
my questions are:
will i get more longivity out of one? will the iron outlast the aluminum?
how many miles can i excpect out of a properly maintained stroker?
i know that iron weighs 100lbs more.
how much of a difference will that make?
Personally, i would go with aluminum. Mainly because i like to put my car hard around corners, be it on the street on some twisty roads or going out to a road course track. I wouldn't want that much extra weight on the nose of my already nose-heavy car. As far as longevity is concerned, it doesn't look like your going to be running an extreme setup, ie 1000rwhp so i think one will last just as long as the other as long as it is taken care of.
But thats just my opinion. So i vote aluminum
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If you throw out cost (which you said you are not worried about), and since you do not have to meet some requirements that state you need an iron block, there is NO reason NOT to go Aluminum.
When done correctly, the aluminum block will take a HUGE beating, and depending on who and what they prep the aluminum block with, can withstand 1500+HP all day long (no, NOT with stock sleeves).
The 427" Dry Sleeve Block (aluminum of course) I have on special right now (until Dec 31st) in my signature is good for 1200+HP all day long....
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I know when I was still working at Katech, we did a durability test on the LS3 block and we finally ended the test at 1500 hours of wide open throttle!!!! The pistons were replaced at 750 hours, but the block was great.
So, aluminum if you aren't worried about the $1000 or so extra. We are doing a 427 from a LS3 block right now for $4599.99 + free shipping to the lower 48.
i like iron personly, seasoned iron. when you build off of a used block and have all of your machinig done to it, it usualy hold truer than if you use a new iron or alum block. after it goes through all of its heat cycles it doesnt distort nearly as much.
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Aluminum gets my vote, my personal build is an LS2 457 but we do build an LSX 434 for extreme power add use. I would say we see 75% aluminum vs 25% iron on big cube builds but anything under a 427 is usually and iron block and now a days more than likely a power add as well.
For the 402 vs 408... I'd stay with the iron block to save money and put it into the top end if I was on a tighter budget. The top end makes the power.
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i like iron personly, seasoned iron. when you build off of a used block and have all of your machinig done to it, it usualy hold truer than if you use a new iron or alum block. after it goes through all of its heat cycles it doesnt distort nearly as much.
i agree. they do seem to hold cylinder ring seal better.
well maintained with a safe tune i think the either will hold up, but in case of failure you may just be able to hone the iron block and reuse it where a failure in a aluminum block probably means replacement.
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If you are going with that size displacement, Aluminum is the way to go. The iron blocks have a slightly shorter sleeve then the aluminum blocks, which only becomes a problem when running 4" stroke or bigger. Plenty of guys though running iron 408's with no probs, So I'd do it mostly for the weight. No other "good" reason to go with the iron if money isn't a problem.
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well maintained with a safe tune i think the either will hold up, but in case of failure you may just be able to hone the iron block and reuse it where a failure in a aluminum block probably means replacement.
Well, actually if you are talking about "failure" an aluminum is teh way to go, as an aluminum block can be repaired, and an iron one is gonna be junked.
Then of course, with aluminum you can go big sleeves for even more cubes.
Quote:
Originally Posted by formula17
+1 aluminum
If you are going with that size displacement, Aluminum is the way to go. The iron blocks have a slightly shorter sleeve then the aluminum blocks, which only becomes a problem when running 4" stroke or bigger. Plenty of guys though running iron 408's with no probs, So I'd do it mostly for the weight. No other "good" reason to go with the iron if money isn't a problem.
Agreed.
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281-732-8215
Dealer for Monster Clutches 90MM TB on sale $275 and 92MM TB on sale $299
On special: 427" ERL Shortblocks only $4500 500" ERL Super Deck II shortblock only $9500
I honestly cannot tell a difference after putting in my iron block 408. The nose of the car sits about a 1/4"-1/2" lower, but that's the only noticeable difference. Taking corners hard and such, I do not feel any difference at all. The car handles just as well.
One noticeable difference that noone has mentioned is that there is more underhood heat. I was actually surprised how much warmer it gets under the hood with the iron block. The motor itself does not run hotter in terms of coolant temps, but it does produce more heat under the hood than the aluminum block did.
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1998 NBM Camaro SS Hardtop M6
LME 408, stock 243s, Pat G cam, ARH longtubes, TSP duals, 12 bolt, LS7 clutch.
Personally i would go with aluminum if money is no issue. Lghter and just as strong for all intensive purposes. Theres a buddy of mine on here running 8s onsistenly with a forged ls3 and alot of Nitrous. So to answer your inquiry i would go with Aluminum.
The short block prices from these sponsors are out of control. I cant believe the stuff you get for the price. In the days of $800 plastic intake manifolds I never thought Id see fully prepped and forged 400+" aluminum short blocks going for UNDER $5,000.
The Morris Motorsports offered Superdeck 1 shortblock literally brought tears to my eyes. If I did the math right with a 4" stroke were talking a 443", 7.3L with Dragonslayer quality crank held down with billet mains and Manley Pro Billet rods for $6,500 bucks? Awesome.
Yes, it is a great market now. It used to be you'd have to spend $6K-$7K just for a 383 stroker that reused your stock block. Now, you get a brand new block with forged internal for under $4K.
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1998 NBM Camaro SS Hardtop M6
LME 408, stock 243s, Pat G cam, ARH longtubes, TSP duals, 12 bolt, LS7 clutch.
It's amazing what happens when parts start becoming readily available. You have to remember, the greatest engine platform ever has only been out for a little over 12 years.
They have had since 1955 to make small block chevy parts!!!!! And they still don't compare in quality to these new engines, not even close.
Iron VS. Aluminum block pros & cons 402/408 
Tim's Automotive Center
