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V-8 Engine Tech

Rocker selection with Jensen rocker covers

Mopar Big Block Talk

by PeterHume » Mon Sep 17, 2018 9:39 am

Hi everyone
This is my first post, I am in Western Australia and I am restoring my 72 mk3 interceptor
I am intending to install a hydraulic roller cam with around original durations and slightly increased lift
(Lunati 20230711)
I would like to use Comp Cams ultra pro magnum (1621) rockers.
My specific question is, can anybody confirm if these rockers will fit under the Jensen rocker covers?
Thanks
Peter
Peterh
72 mk3 interceptor 128-4846
Western Australia
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by AndrewP » Mon Sep 17, 2018 11:32 am

Hi Peter,

Sorry I cant help with your question, but as you can see I'm in Perth too.

Id be interested to see your car and the progress...I'm also the WA secretary for the Jensen club here so we'd be only too happy to add another member to the club.

Drop me a private message here if you'd like?

Cheers

Andrew
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Interceptor Mk3 #1284312
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by Roh » Wed Sep 19, 2018 12:12 am

You can always add an extra gasket under each rocker cover for extra clearance. This has worked for me on Ford Clevelands.
1964 Jensen CV-8 II
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by PeterHume » Wed Sep 19, 2018 12:53 am

Thanks Ronan
That sounds like a possible plan B if I can't get a definite answer :)
Peterh
72 mk3 interceptor 128-4846
Western Australia
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by Dino Fritz » Wed Sep 19, 2018 6:27 am

Hi Peter,

I have a suspicion that you'll be fine with clearance (just to be sure, try installing the rocker covers without the gasket and using plasticine to measure the clearance), although on one of the rocker covers, there is a steel baffle which may cause some grief.

There's about 8-10mm clearance between the baffle and the back of the rocker cover, so consider milling around 5mm off the back of the plinth that holds the baffle in place, and I reckon you'll be okay.

Good luck,

Dino
Jensens.........when does it ever end!
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by PeterHume » Wed Sep 19, 2018 9:30 am

Hi Dino
Thanks for the suggestion, I have seen the baffle you mention.
At present I have not yet bought any rockers. However, the comp cams ones look to be of similar dimensions so hopefully they will be ok. Being steel, they are far less bulky looking than the alloy ones. Unfortunately, nobody stocks them over here so it's a bit of a leap of faith.
Regards
Peter
Peterh
72 mk3 interceptor 128-4846
Western Australia
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by Roh » Wed Sep 26, 2018 7:45 am

I'll be interested to hear how you find the camshaft.

I'm certainly considering a hydraulic roller setup or perhaps a solid roller with solid bushings. The goal would be to have the same idle characteristics as the original camshaft.
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by PeterHume » Wed Sep 26, 2018 10:39 am

Hi Rohan
I have bitten the bullet and ordered the rockers. I will post my findings of a trial fit for the rocker covers.
Regarding the cam I have heard good things about the Lunati voodoo series. It will be at least a year before I get to run the car but the advertised specs of the 20230711 are almost the same as the original but with higher lift and more aggressive ramps. It is also advertised as suitable with a 2000 rpm torque converter (same as original) so i expect it should be quite well behaved

Peter
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72 mk3 interceptor 128-4846
Western Australia
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by Roh » Fri Sep 28, 2018 3:42 am

If I'm right your 440 originally had:

Advertised Duration (Int/Exh): 268/284
Duration @ .050 (Int/Exh): 214/225
Gross Valve Lift (Int/Exh): .450-.464
LSA: 115

Voodoo Retro-Fit Hydraulic Roller Cam - Chrysler 361-440 270/278

Advertised Duration (Int/Exh): 270/278
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .515/.530
LSA: 110

The duration at 50 though looks very similar and the extra lift is nice. I'm guessing you will actually get even greater gains if your new rockers have a greater ratio. The smaller LSA would be my concern as it will mean a rougher idle, less vacuum and a narrower torque curve.
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by Roh » Fri Sep 28, 2018 3:54 am

Crane Cams
Part Number:689511
Duration at 050 inch Lift: 214/222
Advertised Intake Duration: 276/284
Valve Lift with Factory Rocker Arm Ratio: 0.488 in./0.509 in.
Lobe Separation (degrees): 112

Erson
Grind# RH-286-340
Duration 218°/226° @.050 Int/exh
Lift w/1.72 stock rocker ratio- .510 in
Lobe Center 110 deg

Comp Cams
XR274HR-10
224 230
274 282
.538.534
110°

COME Racing (in Melbourne)
CSBR 556
213 219
288 288
Lift at camshaft .307 .322
LSA 112

I'm not sure if COME still do camshafts but some of their LS grinds look appropriate and I'm sure they could be done on Chrysler Billet. Certainly worth a call.
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by PeterHume » Fri Sep 28, 2018 9:46 am

Hmm more choices.
I have rechecked the lunati cam specs and the LSA is quoted at 112 deg so I am thinking it should be ok?
I did look at the crane cam and I suspect it would be very similar
The other one I am considering is the Howard CL723315-12
Duration 272/278
Lift 510/500
LSA 112deg
Again it seems very similar, so it might come down to price..........or the voodoo name :D
Peterh
72 mk3 interceptor 128-4846
Western Australia
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