Aluminum Big Block

[WT101]

Anybody running a ZL1 Aluminum Big Block? If so, several questions:

1) What model are you running it in?
2) How many cubes?
3) Running a power adder of any sort?
4) What are your impressions of it?

[Vegas69]

I'm your man. I have a 489 ZL-1 with 666hp and 641ftlbs at the crank. Naturally aspirated and built by Jason Pettis at www.pettisperformance (http://www.pettisperformance). He's the man. It's in a 69 Camaro pro-touring car. Very happy with the performance and block. I wouldn't trust JUST anybody to machine your 5000 dollar block. It will need multiple mods to make it work.

[WT101]

What kinds of mods we talking about?

[Pro Stock]

Is the block one of Gm's replacement blocks such as part #12370850 or similar?, if so their isn't any special prep work that has to be done other than torquing the heads on the block with head gaskets and then removing them before any machine work is performed, this sets the sleeves in the block, then do any decking that you need to do, the sleeves will still settle a bit more after you've run it but not much more than .001-.002". Also use head studs. if you want max power for your combo then plan on re honing the block after several dyno pulls, we started out at 718 hp at the flywheel with our 470ci Big Block and had the initial tune in a good spot after about 6 pulls, when we got to about the 10th pull it started losing power a little but we had to get it off of the dyno and get to the Engine Masters Competition, we started out good at the competition but by the time we had made all of our tuning pulls and competition pulls the engine was down a total of 40hp.
We took it back to the shop and tore it apart expecting to see that we had started to grab a bearing, the bearings were fine but the cylinders were stupid out of round, this time we went for the gold and hot honed the block and when all was said and done we picked up the power that we lost +7.

By engine Masters rules that year we had to run a flat tappet solid or hydraulic cam and 92 octane spec gas, wet sump with no vac pump, part numbered headers that had to actually fit in a car and street legal mufflers. We had also run this whole combo inside of a new iron block and saw the same numbers but didn't have to do the re-hone. Good luck

p.s. If you need any advice on the top end let me know.
Dale

[Scott Parkhurst]

I was going to recommend you ask Dale about this, but he beat me to it...

(Good to see you here Dale!)

[Pro Stock]

Back at ya Scott, long time no hear

Dale

[Vegas69]

I had to notch my cylinders to clear the rods for starters.....

[Pro Stock]

I had to notch my cylinders to clear the rods for starters.....
We had a 4.600 bore by 3.52 stroke equalling 468 ci so clearance was no problem.

Dale

[MarkM66]

Pro Stock,

What made you decide to use an aluminum block for that competition as apposed to an iron block?

What cubic inch was it?

[Vegas69]

We had a 3.800x4 7/16 stroke so clearance was no problem.

Dale

I only ran 4.25 stroke. It really depends on the rods.

[Pro Stock]

Pro Stock,

What made you decide to use an aluminum block for that competition as apposed to an iron block?

What cubic inch was it?
We, had a connection to GM and they were interested in a A-B-A test to see if the blocks would make similar h.p. If you get the cylinders round and keep them round the block will make as much h.p. as an iron block. If I remember right the block was about 125 lbs lighter than a iron block. The engine was 468 c.i.

Dale

[MarkM66]

We, had a connection to GM and they were interested in a A-B-A test to see if the blocks would make similar h.p. If you get the cylinders round and keep them round the block will make as much h.p. as an iron block. If I remember right the block was about 125 lbs lighter than a iron block. The engine was 468 c.i.

Dale

So was there any difference in hp comparing the two?

Is the build featured online somewhere?

What heads did you use?

Thanks for the info.

[Vegas69]

It's 150lbs lighter than a Gen VI iron block.

[Pro Stock]

It's 150lbs lighter than a Gen VI iron block.
wasn't sure about the weight, thanks.

Dale

[Pro Stock]

So was there any difference in hp comparing the two?

Is the build featured online somewhere?

What heads did you use?

Thanks for the info.
They ended up being pretty equal, I gave some details in the last paragraph of my original post. Due to the fact that we had problems at the competition and didn't win there was no article written on the build, we used Brodix BB2 castings and single plane manifold that I did the porting on, thanks for asking

Dale