I have a chance to get both long blocks. Both are used and hurt. Iron motor has no oil pressure and the aluminum one has a miss fire on #1. I'm pretty sure its just a burnt valve. My question is which on is better. I know the aluminum is lighter and the iron is stronger. I'm staying NA and mildly built. I'm just trying to find the pros and cons that are not so obvious.

 

Aluminum, but since you didn't specify year range i cant tell you the specifics.

Most likely higher compression and better flowing heads for performance use.

 

They are both nnbs, I think 09. The aluminum is in a 4wd and the iron is in 2wd.

 

Then there probably fairly similar.

 

I guess what I'm trying to ask is what would be the preferred one to build. Its going in my sons 67 step side.

 

I would get the aluminum one. The liners are actually fairly thick in them. and there is not going to be much difference NA except the weight.

 

I guess I knew the answer I just had to hear it. Lol

 

I haven't had much experience with aluminum blocks besides the ones that overheated, warped and died. I know aluminum is lighter by about 90lbs, but iron block variants have usually been tougher.

 

iron holds heat much more than aluminum, ask me how I know.

I now have a ron davis radiator.

 

I have a L33 aluminum block and its been great so far. only bad thing is be careful when you are tightening bolts in it