Aluminium or iron block?

[Fordzilla]

I've had both & I agree with all 3 posts above me. The lighter weight of aluminum does help a little in handling & a little in straight line performance, but unless you are racing, it is irrelevant. Yes, bolts will loosen slightly for some reason with aluminum, and it never seems to stop (They constantly loosen). I run only iron now & am a firm believer in a good seasoned cast iron block.
Just my 2 cents.
Regards,

[edwhite7]

You will notice the difference in the corners and you will need to pay attention to hardware. I have lost engine mount bolts and header bolts before I learned to check everything any time I look at it. I have an early torsion bar suspension and I had to reset the torsion bars after changing to the aluminum block and heads. I have a Shelby block with Dove heads and intake. I have had no problems with the Shelby block and would use it again if I needed another one. I can't say the same for the other stuff.

[patrickt]

... if you have to pass an emissions test. Many states will set your emissions based on the year of the block. Oh, and savvy inspectors are not fooled by an aluminum block with "period correct" codes on them.

[undy]

Originally Posted by patrickt

... if you have to pass an emissions test. Many states will set your emissions based on the year of the block. Oh, and savvy inspectors are not fooled by an aluminum block with "period correct" codes on them.

Except in our state, Virginia. 2007 legislation made it so any replica must comply with emission standards of the year that the said replica represents.