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Discussion Starter #1
I'm a bit torn on which cam to run. I'm tossing around between two different Comp Cams;

PN 12-249-4, with 206/212 duration, 0.434/0.444 lift, 112 lobe separation
PN 12-306-4, with 206/212 duration, 0.425/0.44 lift, 108 lobe separation

As background, I'm in the process of rebuilding my chevy 350 tbi motor out of a '91 K2500 4x4 into a 383 stroker for towing and daily driving. I'm going to be running Vortec heads, a 454 TBI, about 8.8:1 compression ratio, with Thorley headers and flowmaster single 3-in exhaust.

For those more experienced, please let me know which of these two you would choose and why? Any other suggestions?
 

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Are these roller cams?

I would go bigger.

something like: 215-225 duration .460-.470 lift

Your 383 will thank you for it. And it will be very daily driver.

If it were me I would go even bigger no questions asked. But I'm quessing you want to keep it very tame.

Blake
 

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Well, basically the same, except lobe seperation. The 112 will give a smoother idle, and a bit less low end torque.
The 108 will idle a bit rougher, but will give you more low end.
Since you are building a 383, you can go with the 108, since the cam is so small anyway.
I personally would go a bit bigger for a 383. Maybe the next step up from those listed.
Phil
 

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Jolleyman said:
I'm going to be running Vortec heads, a 454 TBI, about 8.8:1 compression ratio
What pistons are you running to get 8.8:1 with the vortec heads on a long stroke? Just curious. Also, check out the Comp Cams 'Xtreme Energy 4x4' cams. They are supposed make incredible torque!
 

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I would go bigger too. The cam in my 383 was 488 lift 280 duration on a 110 center lobe. This cam was awsome in my 64 Elcamino! I had Eddie at Camonics in North Hollywood cut it. I have since recammed it for smog purposes. When I rebuild that motor I will be giving him a call (if he is still around it was 14 years ago) for my next one.
 

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Discussion Starter #6
I'm going to run Keith Black pistons (KB121). There's a helluva deep dish to them to keep the compression at 8.8:1 and I'm going to run 5.70" eagle rods.

These are not roller cams, they are hydraulic flat-tappet. I don't want to shell out the cash to convert to a roller and I think the benefit would be minimal for what I want to do with this engine.

As for lift, I'm looking to stay within the lift range for the Vortec heads (0.450 max). I don't really want to upgrade springs on a new set of heads and I don't want to have to deal with potential rod clearance issues if I don't have to.

I'm looking to keep it somewhat tame since I will need to pass emissions and it needs to work well with the computer. The main rpm range will be from idle to maybe 3500-4000 rpm so this is a torque motor and I'm also looking to maintain or improve upon fuel economy if possible. The truck sits on 33's and will be used for daily driving and weekend towing of my trailer loaded with Jeep and a fairly heavy cab-over camper so it will be tugging around some weight.
 

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not trying to change the subject, ive asked other places about this and got no response. but im wanting to put an aftermarket cam in my truck also, something to make it sound like it idles a little rough, sort of how a harley motorcycle sounds at idle and im wanting more power. its a 1992 4.3L TBI engine, anyone know of a good cam for that truck?
 

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I don't know the part numbers, but I built a 406 for my old 90 GMC. Kept the TBI on it, used KB pistons with approx 22 cc dish, 350 rods, stock heads, comp cams extreme enegry 268, roughly 10 to 1 compression, with 87 pump gas, never pinged, headers and 3" y pipe into a flowmaster, then dual 2 1/2 out the back. You could hear the lope of the cam, and it didn't effect the computer at all, no lights coming on, and that thing would scream. It was 2wd, and if it weren't for a tired tranny, it would smoke them in 3rd. It had gobs of torque, and it would keep pulling all the way up the rpm range, seems like there peek, just kept pulling harder. If you go too big on the cam, mostly duration, then the computor wouldn't like it. Just my .02 bits.
 

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About the same as the Comp cam EDL 2103 is Edelbrocks Performer cam for a 400 288* @.050 .442 lift 112*lobe seps. This cam has a CARB exemption for smog needs. I have this cam in my 383 right now and it seems to work well.
 

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I have been hearing that the comp XE series cams will not last in a daily driver, becasue the ramp is so steep that the flat tappets are really being pushed past their limit. I think you can even hear that an engine with an XE cam sounds like you are running a solid lifter cam. I would look at the crane energizer 266, or a simaler one by crower, in responce to the original question.
 
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