What's the highest real world horsepower anyone has ever seen out of a Predator Headed Engine with a single four?
What Ci and what RPM did it make peak horsepower?

I got a 596" with only 800 thou lift though but 14.3 compression on 112 race gas went 1061 hp on engine dyno and on E85 it went 900 to the hubs running through a 727 and a 9" with a single 1250 APD 3 circuit

This was one that was done last year. Heads are based off the CNC program from my heads from Slawko and intake was ported by Slawko. Carb is a CFM 2.200" throttle blade piece. Its been 5.70 in a stock bodied B body on Caltracs and could take some nitrous as that was the intent originally. Owner has not even tried as he is happy as is. Car is 3900lbs with driver I hear. All steel all factory glass interior etc. Bear in mind dynos are dynos. I actually have a single 4 for mine that will be getting ported soon, I'm sure it cam make those numbers or a bit better with enough carb and mine is a tad smaller cubic inch wise.

You guys running a Iron Block or Aluminum?
Hemi or Wedge Block?

Mark have you ever talked to Dave Norris that races at Keystone about his. They have one in his wife’s dragster.

I have not. PM me his number I would like to talk to him

Mines a World alloy block about 2004 model i think.

Mine is a Wedge as is the one listed. I 99% sure T bars is a Hemi as I know the previous owner.

Mark I sent you a PM.

This is what you can do with predator heads. This one is a 660. 5.125 strokes 4.53. I just dynoed this one again after damaging it about a year ago. The motor made more power before the repair NA because the chamber was smaller by 12 CCs. The motor is better for nitrous with the slower, larger chamber so I'll leave it as is. The damage came from using the junk che guides indy provided with the heads (I know better but didn't want to wait for real guides). The guides have but one saving grace. I dont think they'd ever grab a valve as long as you could beat it into the guide. The down side is they break with any real heat if you leave any part of them exposed in the exhaust. The result looks like a cigarette load expoded, all mushroomed out with frags going everywhere. I run 2.49 intakes, and shrank the exhaust down to about .04 between them in overlap. Losing control of the exhaust valve when it closed on a frag wacked the valves together and broke a spring. To fix it required sinking the valves and blending the camber back down to the valves giving me 12 more ccs. Taking compression from 14 to 13.

Chuck at best just did a smaller one that got over 1300 too so for anyone that wants to say it cant be done, tell chuck too lol. A max effort NA will make 1400 if you go after it properly. This sheet is with the larger chamber down close to 30 from the chamber increase. Also now requires 1.5 more degrees timing




Starting from scratch use a hemi block . The wedge requires plugs in the intake to access the inner valley bolts. Limits porting, and weakens the guide boss.

Sombody said, to do the Predator right, you need to change the lifter bores on the Hemi block as well. What were they referring to, angle, or spacing? Does the stock Hemi layout work, or do you guys order a special Hemi block?

You can use a 48 degree block, but you'll need to use a key way lifter of a something like a ts jesel tie bar, where the bar is between the tappets, not over them. The pushrod will hit normal tappets. Having the block on a 45 is better.

So is that a lifter angle of 48*....But stock spacing?

Yes mine is a hemi block.

45 degree for standard cam height, and 48 for raised cam normally. Having the option to choose, go with raised cam 45 degree cam bank angle. All it does is stand the tappets up more in line with the pushrods. Spreading always helps, but isn't necessary. Most shelf tappets will deal with .100 spread. .05 each direction. Straightening the pushrod is a good thing for as much as it's feasible. Like I said earlier a 48 will cause issue with the tie bar on standard type roller tappets. Jesel makes a center tie bar that works on a 48, but they're around 3 thousand dollars. They are worth the coin if you're stuck on the 48

As for cam tunnel, a 54.5 mm is 2.125 ford cam size. 55, 60, 65, 70 in my opinion is unnecessary given the rpm range these heads work at with normal cubes. You'll have rod to cam clearance trouble with aluminum rods anyway, so why compromise the rod with a huge cam core that doesn't help anything at these rpms. Go to a 1 inch tappet with a larger wheel than a .904 if you can, and run 1.9 ratio rockers if you're running shelf stuff.

You don't have to change any of it, but you'll need a center bar lifter like the jesel ts tie bar if your block is 48 degree cam bank angle.

In a perfect world I'd do a 45 degree raised cam, +.5 deck block with the lifters spread .1 in each direction for a total of .2 spread. Going more than that on a stock config block will cause the lifters to hit the center cam bearing.

Next question, why are the heads still $12k?

A guy like me that has pretty much wants to go fast in a bracket type car would love to do a 572 or 605 one of these, but the heads at $12k puts it out of my range by a bunch...Is there really that much machining in them? I am thinking these would be way better than my Hemi heads that flowed in the 450's.....So technically, all I would have to do is change cam, pistons, heads & intake, headers. vs. maybe RBRE rockers......Sure lowers the possibility of a dropped valve some.

12 G is with manifold valves springs rockers covers. They are the best thing out there as far as I know.

The hilarious part to me is I was just looking at a hammer headed small block ford at engine systems. 500+cfm small block head, copied after a boss 9 head. 400ci 1100 hp at 10,000 rpm NA. Those heads are cheaper than the predators lol...they also use a wedge manifold so there are dozens of shelf manifolds . Single 4, 2 x 4, blower , turbo, efi shelf manifolds...those heads are also offered as direct bolt on for the chev LS platform...alas, no mopes

I so wish mopar had these options. I still love a blown hemi though...and that still is the top dog in all drag racing period end of story lol

My stuff is clearly not worthy here for sure. As for the price its like most other things IMO the "mopar tax" can be high on some stuff. There are alot of Predator headed engines around here in the midwest for sure, I was actually surprised at how many there were honestly. I went to a Q16 race at Kil Kare and there were 4 other Stratus's there I was in shock. All but one had a Predator, I was the only NA one there as well as a couple predator dragsters, a Duster and a Barracuda.

I don't see many in georgia either, unfortunately. The mopar tax is for sure a thing, and in some ways self inflicted. Every new mopar product has to endure years of scrutiny, and derision, to the point of failure before anyone will buy it. Ford, and chevy has such a large base, anything made will sell enough to keep the doors open. Our mopar providers take it on the chin, even with a home run product like these predator heads. These heads should be the must have head, period. Should indy see enough sales, they might consider doing what need be done with them. The ports are so small in these heads to start with, it takes effort to get them opened up enough to work, and even at that it's not enough.

We can still thank the 426 hemi for keeping the brand relevant. I watched all the 481X stuff be hailed as the next thing to overtake the hemi. Now I see them all coming out, and hemis going right back in lol.