Pros & Cons of an all alum 351W stroker 427

[maxum_101]

block is a dart alum piece 4 bolt mains afr heads cnc ported, now what are the pros and cons of an alum block as to a iron dart block with the afr heads?

[McD00]

Originally Posted by maxum_101

block is a dart alum piece 4 bolt mains afr heads cnc ported, now what are the pros and cons of an alum block as to a iron dart block with the afr heads?

It's lighter and when you blow rods out the sides the aluminum block can be repaired. Boy do I know about blowing rods out of engines, but they were all FE's

I'm back from vacation...went fishing for awail...25lb trout damn near drowned me

McVette

[blykins]

Maxum,

The only real difference is the weight savings. If you can justify spending the money, then you'd save probably 75-85 lbs off the frontend.

McDoo, sounds like you need to quit building your own engines.

[vettestr]

I will defer to the engine guru's as to any benefits of iron or aluminum since each is a Dart aftermarket piece. Aftermarket alum over a stock iron block would be a bigger spread. I would guess the alum block to be slightly stronger with benefit of technology and greater manufacture-ability of the aluminum alloy availabilities. Weight savings are not as large as many would think because alum. must be thicker than iron for same strengths.

If you damage an alum. piece it can be repaired much easier than cast iron and made good as new. Just hard to beat the wow factor with lighter weight and repair-ability just added benefits.

[bobcowan]

The strength of the two is about the same.

Some people have reported issues with the steel sleeves not being placed properly. The have to be exactly at 0 deck; no more, no less.

[Slick61]

Originally Posted by maxum_101

block is a dart alum piece 4 bolt mains afr heads cnc ported, now what are the pros and cons of an alum block as to a iron dart block with the afr heads?

on a day-to-day basis... you'll need to take time to warm it up properly (before you dip into that deep well of power).

Pros: weight savings, coolness factor

Cons: cost, slightly more attention to maintenance and fastener torquing/sequencing is required

I was nervous about the aluminum block as well... but love mine. As I looked into it, I found that the Dart aluminum block is quite stout... capable of going well beyond 427 cubes. Mine's running AFR-225s & made 612 hp/615 tq on the engine dyno... the lighter engine brought the vehicle weight in at 2240 lbs., so it's a screamer... winds up fast.

[Chilibit]

Does an aluminum block expand and contract in response to heat in sync with aluminum heads? Does it make a significant difference?

[Anthony]

Originally Posted by Chilibit

Does an aluminum block expand and contract in response to heat in sync with aluminum heads? Does it make a significant difference?

It does. If you run a solid lifter engine, with the engine cold, and especially in colder weather, the valve lash will be alot tighter and may make it more difficult or possibly unable to start ( 40-50 F ).

Iron block will not affect valve lash as much, somewhat with aluminum heads, and not alot with iron heads. If you're running hydraulic lifters, then it doesn't matter for starting. However, with an all aluminum engine cold, there may not be alot of pressure on the head gaskets until the engine is warm/hot, and I probably wouldn't run the engine hard until then.

[sllib]

When you bring the alum. block home from the machine shop and wash it you won't get the thrill of watching the rust grow on the block before your eyes.
Bill Stradtner

[Ronbo]

Lots of aluminum blocks out there, most production vehicles are going to aluminum blocks and if Detroit is embracing it then there's a reason especially since it's more expensive than cast iron.

Pro - major one is less front-end weight.

Con - coolant erosion, watch your coolant choices.

Well actually there is one other con with aluminum, makes your magnetic dial indicator base pretty useless. (as does stainless)

You can screw anything up with enough neglect as McD00 pointed out.

[iwantacobra427]

I heard Al blocks throw off more heat than Iron blocks..

[Ronbo]

Probably does but your cylinder heads are the hottest part of the engine. The major source of heat is of course your exhaust system.