Aluminum vs Iron block?

When I finally build the 440/512 stroker for the Challenger I'm planning out, I'm debating between using the original iron block, or an aftermarket aluminum block. I'm not planning to put this thing over 600-650 horsepower, and it will be mainly used as a roadtrip/occasional daily driver/occasional weekend at the track car. My questions are, with those things in mind, will an aluminum block hold up as well as iron? How do the two compare in terms of longevity and reliability? Also, are the weight savings worth the extra money in terms of performance and handling? Also, if doing a 512 stroker kit in an aluminum block, would that entail boring out the cylinders? If so, would I need larger iron sleeves, and where would I get those?

Lol, I'm glad my posts have been interesting to you guys as of late

If this is a once-in-a-lifetime build do it right and spend the extra couple of thousands for a block that won't break. There are plenty of posts on this topic.

Most aluminum blocks have cast iron cylinders so wear shouldn't be an issue. And even the OEM blocks with spray-in liners have to last 100K or more.

R.

I don't know if it's going to be a once in a lifetime build, but it is probably going to be a once in 10-20 years build. I will probably go with the aluminum block. The question about boring out the cylinders remains though, if I have to do a little bit of boring for the stroker kit, will there be an issue with the cast iron sleeves of the cylinder being too thin?

just being a s....a..
the wait time on an aftermarket block may take awhile.
If you have the time & money to order & wait for an aluminum block you will probably be better off.

Cool, the only thing I'm still unsure of is about the cylinder sleeves and the 512 stroker kit

A 512 kit doesn't need a big bore, so the sleeves won't be an issue. KB will ask you what bore size you want and use a sleeve that will still have room to grow. Mine is 4.500" bore and has the ability to go to 4.530". Your 512" will probably only be 4.375" bore.

The only real downside to an aluminum block is the initial cost.

Awesome! Thank you

If you get the 4.5 bore block, the crank for your 512ci is now a 540ci in the big bore block.
if your buying all new stuff just go straight to 4.5 bore and 4.5 stroke. That's 572ci. You can go to 604ci fairly easy but the 572ci will be nasty

My first pump gas stroker 511 C.I.(4.375 bore with 4.250 stroke)stock iron 400 block made 612 Hp at 5500 RPM and 544 ft lbs torque at 4500 RPM with a mild set of ported big valve 906 heads and stock type six pak intake and vacume carbs. On your deal with a aluminum block build a 4.5 bore with either a 4.25,4.375 or 4.500 stroke with BB Chevy rod journals That combination, either of the three,will make 600 HP on pump gas at 4500 RPM with a set of decent set of unported aluminum heads My 511 became a 517 C.I. by increasing the stroke to 4.300 to move the dished pistons up to zero deck to make 10.29 to 1 compression ratio, I later swapped the heads to a set of M.W. port size Indy SR (10.78 to 1 comp. ratio)and a Indy 400-3 intake with a single 1050 CFM Dominator and that combination made 728 HP at 7000 RPM in Klamath Falls Oregon at 4300 ft above sea leve Good heads on a big C.I. motor make a hoop of power On the aluminum block deal make sure to considered the block growth on the final compression ratio, the aluminum blocks are known to grow between .006 to .010 in hieght warmed up The aluminum block needs to have dry sleeves to work well on the street also, it will loose a little power compared to the same combination in a iron block but on a street car with stock type suspension and stock type tires you will never know the differences in that power. Be very careful in the car until you get use to that kind of power, it is additive and can be very dangerous My 3450 lb. (with a full tank, 18 gallons, of fuel) Duster went 9.993 at 134.7 MPH through the full exhaust system with the air cleaner on using Oregon 91 octane pump swill

That's some scary power My goal was only around 600-650 horsepower, so I think whatever block I go with, I'll keep to the 512 cubes using a 4.375" bore and 4.25" stroke with dish pistons and ported aluminum heads for a 10.5:1 compression. With fuel injection, a windage tray, the right cam, and headers, I'll probably meet or exceed my goal.

Realizing cost differences across the country, any guesstimate on the cost to build this engine by a quality builder. . Whose block would be recommended.?

If you want to keep the CID to just over 500, order the bore and stroke to match. You can even build a 4.44" bore.

528 CID = 4.500^2 * 3.14/4 * 8 * 4.150" stroke

511 CID = 4.375^2 * 3.14/4 * 8 * 4.250" stroke
512 CID = 4.380^2 * 3.14/4 * 8 * 4.250" stroke
526 CID = 4.440^2 * 3.14/4 * 8 * 4.250" stroke
540 CID = 4.500^2 * 3.14/4 * 8 * 4.250" stroke

541 CID = 4.375^2 * 3.14/4 * 8 * 4.500" stroke