Special considerations for aluminum block street car?

I searched here but did not find what I was looking for.

Are there any special considerations for building an aluminum hemi for a street car? I am thinking 528-540 cubes with either a Keith black block or an iron Bulldog block. I like the fact that the Keith black would be easier to repair and that a new set of sleeves and you can rebuild indefinitely.

I have never had anything like this before. What considerations should I be aware of? Sealing, etc? Valve lash changing? If I need to give more information let me know. I would like to build an 800 hp street motor with room to grow later on.

Thank you all for your time.

My last all al Hemi grew over .020 during warm-up (505" KB). Due to the large growth, I felt I had to check the valves much more often. It didn't want to start much under 55 degrees. And I had to wait for it to fully warm up before I jumped on it much. On the street, the cooling system HAS to be up to the task. So, after living with the small, but numerous issues with the aluminum block, I went iron this time and am happy I did. (540" World)

Well, I have had both. I prefer an aluminum block for the weight reduction and the better cooling....Mine ran nice and cool on the street....Growth can be an issue. You do need to check the valves at full temp, no way around it. But once set, they were fine. And yes it has to be at full temp to really beat on it. We were not real happy with the Indy block we got. There was .011" of run out in the cylinder bores and the sleeves seemed real thin and it had other issues like the thrust face not fully machined and a few other things. We were not able to get all the cylinder bores super nice, but we found a bigger issue later. The bigger issue we had was oil pressure when hot. Ours always dropped off and we could not find it. Went thru a lot of trial and error, and could not find it. Ultimately we sold that block. Seems there may have been an issue with the last cam bearing machining and we never found it as the bearings come in the block already, but the guy that bought the block did....

The newer KB will be much better, but stay away from running the bore to max. Keep the sleeves as thick as you can. The 572 is pretty standard these days. I currently have a World Iron block. I am very happy with everything but the weight of it. And I will be upgrading my water pump this year. I have a very good cooling system, but its right on the edge with this 605 and an electric water pump...

Thank you fellas for the replies. I figure Keith Black and Bulldog are my only hopes for a block. I wish I could find someone who has a block tucked away somewhere....

What about using a hydraulic roller cam in an aluminum block ?

I am considering this myself. Yes, it makes an expensive engine (with the Al block that is),
but evidently you can rev a Hyd roller to 6500 or so, or even more. I think this especially true
if you use titanium intake valves, which of course adds even more cost to your already expensive engine.
But I have not heard a good argument against Ti intakes except for cost.

I think a motor like this would make a goodly amount of reliable, maintenance-free horsepower.

There are people who have them, and have had to pay to get them so when selling they are not going to give them away on the cheap. I have $9000 Canadian into my block with all the machining at FHO so
unfortunately if you want a new Hemi block you will have to do the same and pay. Good luck in the search.

Mine's been great since originally built in 2006. It's a KB block.
My lash grows about .012" cold to hot.

Chip, what is your oil pressure at idle at start up compared to idle at 180 degrees?
I have an aluminum Indy block on my 528 Hemi, it's about 75psi at startup, while cruising its about 35psi at a stop light when warmed up. I have the oil restrictors in the heads.

That's about what I see too. 75-80 cold, 30-35 hot idle. As soon as you hit the throttle it's back to 65+ real quick. I've run this thing so long I barely bother to watch it now, lol.

That's good to hear, mine does the same thing, barely touch the throttle and the oil pressure shoots up.
Thanks Chip! Your video on FB is incredible, car is a rocket.

Here you go.

https://www.ebay.com/itm/426-hemi-engine-block/283503714773?

If you're only going to rev to 6500 I don't know what good titanium valves would do you.

I think it may be difficult to get 800hp out of a 540" Hemi with only 6,500rpm. My 540" Hemi with 250*sft cam and Modern ported heads made 697hp @ 6,800. Mine is probably not perfect, but it is not likely that there is another 100hp with less rpm and the same cid.

Boost...

Kevin

With Ti valves you can use less spring pressure for the same max RPM.
The Hyd roller lifters like this.
And the lifters take up the extra lash from the Al block growing.

Barely used 540 Mopar (World) short block assy block here that I won't use. Didn't you get that PM?

Airwoofer you can PM me the info I might be able to help clear some space.

As for an aluminum block on the street. Have you not been paying attention in new cars. THOUSANDS if not MILLIONS of cars are on the road with aluminum blocks. IMO the biggest issue is going to be corrosion. If you are gonna be driving the thing for many years I would suggest a getting a Magnesium Sacraficial Anode. There are some that attach to radiator caps and others that thread in. Its just a good idea. As for valve lash, yes they grow more, as for getting on them cold. Happens at the dragstrip ALL the time. I have an aluminum block in my TS car. We tow it to the line and back COLD. Fire it up and make a pass, cool it down and repeat. No issues at all. The do pull heat away much more efficiently than an iron block so you can get away with a fair amount more compression on pump gas(race gas too)as well. One of the only "issues" other than corrosion would be a loss of cylinder pressure over an iron block. Again because the aluminum is much better at dissipating heat than iron is.

Good advice so far. I second the comments to make sure you have a good cooling system. 30-40 PSI oil pressure at idle at 180 degrees will be under 20psi at 200+. As far as lash I didn't see then changing with good rockers. I checked them a bunch at first and they never changed. I made 800 HP with a 557" motor on pump gas, it was around 850 on race gas with more compression and a bigger cam but I turned a little more than 6800. Lot's of years ago but I recall peak HP was around 7500.

If this is going to be a true street engine I would look at setting up the main bearing clearances on the tighter side. Spent years working around BBC marine engines that were all aluminum. The engines used Donovan aluminum blocks with a 3 inch main bearing for increased strength. The main bearing clearances were set at .0018 due to block growth. We used hydraulic rollers as these were not high RPM engines. 5500 was about max RPM but these engine would spend most of their life in the 4000 RPM range when not at idle. The engines stayed relatively cool since we have an unlimited cooling supply of water. Engines used a closed cooling system with heat exchangers with a normal operating temp of 160 degrees. Also used Mobil 1 15-50 for oil.

With that being said there was a lot of time and testing put into determining what worked best for that particular combination as far as clearances go.