Received my stealth heads back from Modern today. Bob was good to work with and everything went as planned and looks good. I realize this is pretty mundane stuff by this boards standards, but I’m pretty jacked up to see what this does for my 451 Satellite combo.

Question is: how much will it pick up?

My combo has been listed here many times over the years, but here it is again for reference:

400 block .040 over
Factory RB crank
Iconn flattops with 4.5cc reliefs at zero deck
Engle custom grind: 252* @ .050 / .573 lift on a 109* cl (square)
1000cfm Holley annular HP
Eddy RPM with a 1/2” open spacer
MSD Digital 6+ box & Mallory mag pickup dizzy
1-7/8” Hooker Comps
9-1/2” Dynamic converter (flashes to about 4K)
Pretty basic manual 727
Full Calvert suspension (springs, bars, & shocks)
4.10’s & 28x9 slicks
Car has weighed 3820

Previous best is in my sig below. In the heat of the summer it was typically in the 11.52 - 11.56 range.

Changes: the heads you see here were previously OTB with as cast 84cc (??) chambers, good for 10.42:1. Heads are now are a verified 82 cc’s, good for 10.62:1.
Adding a mild steel 6 pt bar. Probably about 60 lbs (??)




[img:left][/img]

Were they flowed before port work?

Are these later castings?

No, they were never flowed previous. These are earlier castings. I believe they were some of the last of the 84cc versions.

So we can probably assume, they flowed in the 260 to 270 @.600 range?

Your combo is very close to my 470, except intake 😃 and I have a roller. If it doesn't go. 10.5X. (With a Thumperized Dommy) I'll be really irritated.

Yeah. That’s what Ive seen in various flow tests. Source claims 290, but most here agree that’s a happy bench. My logic tells me that now my cam is the choke point.

My 440ci with sft 258@050 - .520 net lift with otb stealths went 10.998 once, mostly 11 low teens . Went to cnc stealths car went best 10.88 mostly high 10.90s /11.00s . Engine was not altered , pinch more comp ended at 10.8
I had more stall , 5000 . And just under 3700lbs . Eddy victor intake
All through street exhaust and mufflers dumping at diff , same 1 7/8 hookers .
So around 2/10s or so .

Tex

Isn't the cam a kv/hv3 grind, or at least lobes.? I have the same cam, but on a 106. Pretty fast lobes.

Yes! It is a KV-3 on a 109 cl

The head porting likely added around 60cfm...... With a radius plate on the port opening.
The RPM is a bit of a flow restriction, so with that in place...... And depending on which manifold runner you're testing....... The gain would be more like 30-40cfm.

Usually it comes down to this......... If the flow of the heads/intake manifold were the major restrictions to the performance of the car, then improving them will yield big gains.
If you dont see the kind of pick up you're expecting....... Then they weren't holding you back as much as you thought.

With the RPM intake, on that combo........ I'm going to say a 40-50-ish hp improvement.
So, if you get that much improvement in power, and make the best use of it, at the current performance level of your car........ 4mph and .4 ET.

My gut feeling is more like 2.5-3 for both ET and speed.
Maybe more with some tweaking.

Cough cough....😎

and he already has an annular carb, do a manifold swap at the track and tell us what you gain or lose !!!

Happy bench?
More like...... No bench.

As I recall, their flow numbers were exactly the same as the numbers for Edelbrock RPM heads.

I would like to see the results before you add the cage

HaHa! Touché, and score one point for Von.

I'd like to see that as well, unfortunately I won't be able to pull it off. Bar is being installed right now, track won't be open until late March at the earliest, and I need the car to be legal at seasons open.

My mild steel 8-point bar added about 100#, FWIW.

I, too, think the Performer RPM is the next choke point. Got the hood clearance to try a tall(er) single-plain intake like a Trick Flow?

Did you ever state your performance goals?

How did that one piston look when you pulled the heads back off?

I think 11.teens @ 120, maybe a dip into the 11.0s

Adding weight by adding a roll bar to your car may help more than hurt by stiffening up the chassis. As far as gained cfm who knows as he didn’t provide before and after numbers. I had 4 sets of the Source heads on my flowbench and they all averaged 267 cfm out of the box. Bolting on any untouched intake manifold is going to kill power but easily fixed during your next upgrade. Good luck and have fun.

Hard to say, you've added weight but also gained a little comp. Question is does your combo need more CFM airflow from the heads. Could probably benefit from a little more.

Your combo is running pretty good for its 3820#,s The RPM might be a little choke up top , but the spacer does give it a little more cushion. But with your 252* cam and 4000 stall vert @ 3820# you Want that RPM intake, choking or not. Its whats helping you move that car below its torque peak which is around 4500 with that cam.

Its going to be faster for sure, but only by maybe a tenth or two at most IMO... With your car being so heavy, I think advancing the cam to around 104/105 ICL would help too, verses being straight up on a 109 icl.

Nice combo.

I assume you’re talking about the piston tops (2 & 3) that seemed fuel washed, cleaner than the others, last time I removed the heads? They were similar but not nearly as bad. Fuel distribution is the issue, I’m sure. I’ve changed carburetors and added the spacer since then. All the spark plugs look identical. So, still don’t really know what to make of it (???).