Dyno shop tested 318

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Stroked408

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Not sure what section I wanted to post this thread but I figured this would be a good start. I picked up this 68 Dart at the beginning of January and I was curious as to what kind of power it was putting out. I was only given a limited amount of information about the engine build but it sounded pretty mean (3" exhaust turned down before rear axle). Full disclosure: I'm not an engine builder or tuning guru, so bear with me if I don't have all the information correct. All I wanted from this trip to the dyno shop was a baseline and a little tuning.
First off, I knew I had a exhaust leak at the passenger side header but I didn't get it fixed in time for my appointment. The distributor seems to be some knock off billet brand that may have an issue. We also figured out that the oil breather on the driver side valve cover needs to be replaced with the fill cap, as the PCV valve is on the same side. It was creating a lean condition. I would also believe that the 750 Holley is a bit too much for this setup, maybe a 600 cfm might do.
Here are the specs:
- 318 w/ RPM Performer manifold, Holley 750 double pumper
- Lunati cam & lifters (p/n 71977-16) adv. duration 290/290 @.050 240/240 lift
- Gross valve lift .520/.520 LSA/ICL 106/102
- Forged Pistons (brand unknown, compression ratio unknown)
- Stock iron heads w/ minor polish (heads/manifold port matched)
- Doug’s long tube headers, 3” exhaust w/ Black Widow mufflers
- 46RH overdrive transmission 2200 stall converter
- Ford 9” 3.54 gears 31 spline axles Diamond locker rear

1st pull: 254 hp. 377 tq. @ 5000 rpm
2nd pull 262 hp. 397 tq. @ 5000 rpm
3rd pull 273.3 hp. 411 tq. @ 5000 rpm

Dart at dyno shop.jpg


dart prep dyno.jpg


Dart ready for dyno.jpg
 
Damned respectable at the rear axle for sure!
 
On the labor notes: " set idle mixture screws, adjust idle, check and set timing, change out secondary jets to 83." Also, they welded in a bung, in the exhaust pipe, for the O2 sensor.

By the way, the shop is Deleon Dyno Performance in Santa Clara, CA.
 
341 at the crank according to this chart.

upload_2021-1-25_19-13-4.png
 
Wondering about the heads also.. I have a .030 over 318 going together right now with 360 heads and kb167 in it. Unknown cam, it says 270 on it with 110 stamped in it. Vic jr with Holley efi 4150 TB. 904 3500 stall. I’m hoping to get those kinda numbers. Like the color and stripe on the car!
 
SlantedDart what kind of 360 heads. What's the chamber size.
3769974 is stamped on them. Off a 74 360 out of a Something lol. not sure on chamber size 1.88/ 1.60 valves I believe? I hope I’m getting close to 9:1. Piston is damn near zero deck to the naked eye.
 
That is a lot of lift for “stock” 318 heads... my stock 2.02 j-headed 318 is going to stay under .500.

If you have stock stamped rockers I assume you are losing some lift. But .520 is still a lot for stock springs.
 
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I thought that was a lot too but I was in a hurry and couldn't find the link to my other chart.


I should say I have ZERO experience with a hub dyno or a eddy current Dyno. All my wheel dyno experience is on drums, so there may be a difference there.

So I could be wrong...
 
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