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Old 10-27-2010, 02:46 PM
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another cam help question

Ok so i just wiped an intake lobe on my cam in my truck so id like some opinions on picking out a new one.

-1984 c10 pickup 4200 lbs, automatic 3000 stall, 4.10s
-350 sbc patriot heads 58cc chambers, 200cc runners, 10.5:1

Im looking for something with more torque to pull my out of the hole. It is a street strip truck and ran a best time of 14.5 @ 99 (maybe that could be due to a partially wiped lobe?). The cam that came out of it was a comp xe284h... too big of a cam for my setup in my opinion but im looking for something more torque. Does anyone have any good suggestions for a heavy truck like mine? Trying to shave some time off of that 1/4 mile. Thanks

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Old 10-27-2010, 02:53 PM
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Ya with that cam in a 350 in a heavy truck you should use a 3600-4000 stall and 4.56 gears.

A Isky #201281 280H Mega Cam will make more low-mid tork for you.
A better match for a 3000 stall behind a 350.
IMHO thee are better quality flat tappet cams.

Even this one can use more gear in a heavy truck.
You need the leverage (gear) to get a heavy vehicle going.
I'd be thinking 4.56-4.88 gearing.

Especially with tall tires.

The patriot heads could probabily use some work.
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Old 10-27-2010, 03:04 PM
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If I ran a taller gear i would loose mph top end. That isky cam is also alot like the previous cam i was running, power doesnt come on until after 2500 rpms. Im looking to bring that down a bit and keep my 410s. Keep in mind im only running a 3 speed and i do drive to the track/around town so a taller gear isnt an option.
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Old 10-27-2010, 04:15 PM
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Quote:
Originally Posted by cbr954rrider
If I ran a taller gear i would loose mph top end. That isky cam is also alot like the previous cam i was running, power doesnt come on until after 2500 rpms. Im looking to bring that down a bit and keep my 410s. Keep in mind im only running a 3 speed and i do drive to the track/around town so a taller gear isnt an option.
Then get a shorter sticky tire for the track.

Run a tall street tire on the street. The truck is a tank, it needs the gear.

When you ran the XE284H-10 did you lock out the advance curve? This cam wants full locked out timing for best drag response and ET
This is how it wants to run on the street too.
Locked out mechanical at 36deg + 10-12deg of vacuum advance
Get some sticky "ET street" tires for the track.

What diameter rear tires were you using?
The net effective gear ratio is critical, especially on a heavy truck.
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Old 10-27-2010, 05:38 PM
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I ran a 28 inch street tire. As for the timing i was running very light mechanical springs, full mechanical advance was in at 2000 rpms. When im up on the converter to launch my timing should have all been in. 18 degrees at idle, 36 degrees with mechanical advance, and 44 degrees total including vacuum.
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Old 10-27-2010, 09:29 PM
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Quote:
Originally Posted by cbr954rrider
I ran a 28 inch street tire. As for the timing i was running very light mechanical springs, full mechanical advance was in at 2000 rpms. When im up on the converter to launch my timing should have all been in. 18 degrees at idle, 36 degrees with mechanical advance, and 44 degrees total including vacuum.
The distributor set up you have is for a manual trans application .
A auto trans application needs a different curve, with much more initial base timing.

The converter works the best when launched right from idle.
Stalling up on the converter in order to bring in the advance curve, kills off the torque multiplication effect (flash stall) and reduces the launch force.

You are giving up 3 to 4 tenth just in the way you are staging/launching.

Lock out the advance and launch right from idle. it will launch and et much better. Should be using a short 26" tire (P235-60-15 or 8.5x 26x 15) with 4.10's and a heavy truck with 350.
A 28" tall tire needs a 4.56 gear in that truck w 350cid motor.

The XE284H cam would have worked fine if yu had the right configuration and setup. You were not using the cams best power band.



Lots of gear, short sticky tire for the strip. tall street tires for cruising.




1.6 sec 60ft footbraking right off idle. In full street trim. Yanks the front wheels. XE284H-10

Even if/when you go to a smaller camshaft, you still want to lunch right from idle to get the best et. Loading up against the converter kills the launch.

You need all the launch force, converter torque multiplcation and weight transfer possible to get the tank of a truck moving, if you want a quick ET.

Last edited by F-BIRD'88; 10-27-2010 at 09:46 PM.
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