Hopefully you don't take this the wrong way other than constructive help... Lots of people piling on with opinions, but I think the one thing that stands out is the low RPM.

When I asked before what ET/MPH/Weight it ran before, I was impressed by the 9.0, but the 146mph really didn't match up very well. I'd think that would be more like 150~151mph.

I wonder if that's another sign of it making good power down low, but not up top?

Did you re-use the valve springs by chance with the new cam? I wonder if they are dead?


Although if you look at your peak TQ at 4800RPM, and compare it to Andy's 572" dyno sheet... even the peak torque RPM is really low.

Maybe try a cylinder pressure test. If it's through the roof it might indicate the cam is really small, or WAY advanced from what you thought.

at the moment its a mystery the headers I found out were 1 3/4 to 1 7/8 step to 3 1/2 collector. That for sure would effect the torque band I believe.

Now I'm curious to know if you had it dynoed the first time it was built?

At this point, my feeling is this is a classic case of “racing dynos/facilities”.

I wouldn’t change anything til after it’s been in the car and made some passes.

That being said, I’d expect the numbers/curve would look quite a bit different if I’d have tested it here.

Could be something with the dyno but I don't know why the power bands would be moved down so much. But I agree, unless the OP is interested in spending money on an R&D project I'd just fix the oil pressure issue and then put it in the car and see what she does at the track.

100psi from a milodon dual line system isn’t uncommon.
Especially in cool air and 100* water temps.

The system as is, has been run in the car for several years.
I wouldn’t change anything till it’s been verified at the track.

As has been mentioned..... this is not a new combo.
It’s a freshen up with a cam change.

Put it in the car and see how it runs.

So, I'm assuming you mean you'd have tried to figure out what was wrong if you had been dynoing it? And now that I think about it more, I'm almost on the fence as to if I'd just stick it in the car and sort it out. It did run good in the past for what it was! And I'd expect the cam would have picked it up a decent amount ...at least bring the RPM up if nothing else changed? Did you dyno this engine initially? I remember talking to him a bit on the phone long ago and he said you'd done some work on this motor...maybe it was just the heads...IDK

Just Asking,,,Is the intake ported? The torque is insane so I think as long as it hooks it will ET very strong and just shift it fairly low and keep in that sweet spot. The intake should outflow the heads ( or to say it better, easily keep up with the heads) and if it doesn't you're leaving some top end on the table. When Larry Smith ported my 337 single plane for my Chapman Max Wedge heads.... it made a much bigger difference through the entire power curve than I even anticipated, it gained peak torque RPM and HP that cost little to nothing below the curve. Any time I see a wedge that torque peaks at around 4500 might seem to be slightly under ported, but the torque you have is very stout for 529 cubes.

So is the cam degreed at 108? that should be about right for that combo I would think but I tend to agree that strokers tend to like a big lobe that's in early because the piston swings back toward TDC quicker (gives up more displacement per degree of crank angle) ...so (at least in theory) you gotta rely more on the intake charge than say a shorter stroke/longer rod combo of the same displacement. I haven't built many strokers on 112 centerlines and of course the headers are less than ideally sized for anything much over 5200-5400 on a motor that big. That definitely is limiting your top end in that your HP will fall off quicker after peak torque compared to a 2" tube.

Is that a B or RB deck height? Just curious. I'd love to have a 4.500" bore to work with one day!

i agree though, the only dyno that matters it the timeslip, should be a great bracket motr that lives a good long time!! Congrats!

What I’m saying is, if it was hauled here and rested with no changes other than my dyno headers, I’d expect the numbers/curve to be so different you wouldn’t believe it was the same engine.

Why I say that is there is one aspect of those results that is a pretty glaring issue for me, that I have never seen here on this type of N/A build before(and have rarely seen ever), and I highly doubt it would be duplicated here.

Of course, retesting it here........ and assuming what I predict would happen, actually happened....... it wouldn’t have any impact on how fast the car goes.

If the RPM numbers on the dyno sheet were 1000 higher, no one would bat an eye...

I have not seen the result of putting that small a primary on a 530 ish CID motor vs a 2.125 or larger. But I am sure it would reduce the peak HP and rpm it occurs at. But that rpm range is strange.
As mentioned by others, I would just put it in the car and do a couple days of testing with different shift points and your (larger) headers. It still made good HP on the dyno with those little headers.

-4.5 In HG manifold pressure? Was the throttle all the way open?

Vacuum reading is crankcase pressure from vacuum pump.

That’s not the issue I have with the results, especially if the headers in use were in fact 1-3/4 to 1-7/8 x 3.5.

Yeah that size header will really choke it down.

You're doing a pretty good job beating around the bush here. What is your issue with the results?

I’m waiting to see if anyone else picks up on it.

It jumped right off the sheet to me.

Cam placement. Eye opener

when I drove there i was under the impression my headers were going on the dyno since that's why i dropped them off with the engine week in advance. they have 2 bungs for afr. after all this being said I cant say it was money well spent since my headers weren't used and they are not true numbers to my combination ,.But at least I have good ring seal something you may not accomplish during your first burn out!

Found the original time slip 9.017 @ 147.89 in good n j air! . that was a 272/284 660/660 cam. I appreciate the impute from all, a lot of good brains at work! I'm confident I'll get my first ever 8 second timeslip in the near future! I

I'm looking at the retarded cam, a/f ratio is lean and the water temp is really low. No warmup?