cam for 402ci

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Oct 10, 2015 | 03:19 AM

ls1 down under

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cam for 402ci

Looking a camshaft for my 402ci. Still running cathedral heads ported with the fast 92 intake tb combo, 1.7 yella terra roller rockers, 1 7/8 headers, twin 3 inch exhaust, 3.45 gears, 6 speed manual, 1640kg car weight on 20 inch tyres.

Currently has 501.9rwhp and I'm pretty sure ex owner had a 232/234 cam in it. Which is good power.

Went to track day last weekend and ran against cammed L92 and LS3 cars with 430rwhp to 450rwhp using cams around 238/242 duration and I couldn't pull away from them.

I'm after something stronger from that mid range to top end.

Any suggestions ?

Oct 10, 2015 | 05:00 AM

96capricemgr

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More vehicle details please.
How old are the valvesprings? They are a maintenance item with an aftermarket cam. They loose pressure and the valves start bouncing off the seat when they close at high rpm causing big loss of power.

Oct 10, 2015 | 05:15 AM

ls1 down under

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Quote:

Originally Posted by 96capricemgr

Quiet possible. Engine has done 20,000km. I might change springs first.

Oct 10, 2015 | 06:42 AM

Tuskyz28

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Exactly what heads are the cathedrals?

Oct 10, 2015 | 06:46 AM

A.R. Shale Targa

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Quote:

Originally Posted by 96capricemgr

Great suggestion here
Also if below 4000 thousand rpm is meaningless to you for these track days, perhaps you could benefit from an LS3 top end as well as a cam change.
Without knowing much about your cathedral heads, which I'm sure offer terrific low rpm response, but the runner volume just may not be able to feed that hungry 6.6 in the 5000-6500 range. If that's the case then a cam change right now would only be a band aid fix for an air starvation problem.

Oct 10, 2015 | 08:10 AM

HCI2000SS

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From: Howell & Fenton MI

We're these other cars vettes that you were racing?

Oct 10, 2015 | 09:34 AM

Darth_V8r

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That fast 92 could use an upgrade to a 102 also. On most 5.7L HCI builds I would say not too big a difference, but on a 402 that is already hungry for air, it would make a difference. Throttle opening is 6650 sq-mm vs 8170 sq-mm just for the extra 10-mm diameter.

Also curious to know which heads. Cathedrals range from the original 806 to the forthcoming mamo250's.

Don't rule out gearing either. You might benefit from 3.73 or 3.89 gears

If you're 232/234 already, you'd need to go at least 240/246 to see much difference from the cam swap

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Oct 11, 2015 | 01:07 PM

Darth_V8r

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Ok so the following depends on your heads being milled or not for PTV reasons. Or your Pistons fly cut.

I would be looking at the global warmer or climate changer from cam motion and other similar sized grinds like tick polluter

240/244-114+4
245/250-114+4
239/244-111+2

Oct 11, 2015 | 01:53 PM

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JakeFusion

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This cam would definitely wake it up, but it'll drive nowhere near the cam you have now:

http://www.engpwrsys.com/index.php?a...d&productId=15

251/259 .624"/.624" 112+2 (but I'd do it on a 113 or 114)

Last edited by JakeFusion; Oct 11, 2015 at 02:11 PM.

Oct 13, 2015 | 07:05 AM

#11

MuhThugga

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From: Wilmington, De

I have a cam sitting on my shelf from Flowtech Inductions. It is a 241/251 on a 112. It didn't play well with my LS3 heads on my 404 in traffic conditions in terms of surging, but it would work really well in a cathedral head application. It did shine in the mid and upper RPM range with making power. Message me if you'd like pics of the cam, cam sheet, and dyno chart.

Oct 13, 2015 | 01:55 PM

#12

speedtigger

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One thing that you did not say is your compression ratio. That can influence which camshaft you would want to pick.

Also, your 3.45 gears are not optimal for drag racing. For drag racing you would do well with a rear differential gearing in the low 4s.

Quote:

Originally Posted by Darth_V8r

Out of these picks, I like the middle one. with the 52.5 degrees after BDC intake valve close and 19.5 degrees of overlap, this bad boy will rock in roll in a 400" engine with cathedral heads. Cam Motion sells this camshaft. It is called "The Climate Changers" LOL:
http://store.cammotion.com/climate-changer

Quote:

Originally Posted by JakeFusion

With an IVC of 55.5 degrees and 31 degrees of overlap, I would not choose this cam for a 400" engine with pump gas in a heavy car and 3.45 gears. I think it would be a dog down low and in the midrange.