Cam options

sntrym said:

The XR258 is old school so you need a new timing cover and a cam button but it provides great top end power with this setup and still gets good mileage

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FYI, with Comp Cams, if you look up the part number starting with 08-***-8 you'll get one that works with a block the has bosses for the spider and cam plate for roller cam provisions.

So, in your case, it would be 08-408-8 instead of 12-408-8 (retrofit)
www.compcams.com/xtreme-energy-206-212-hydraulic-roller-cam-for-oe-roller-sbc.html


OP: be careful with lift height and TBI heads. FWIU max is ~.480" before you have to work some magic on them.

Absolutely upgrade to a roller cam. Call your favorite cam company and get a cam that will maximize your torque.

The Lunati cam in WCJr doesn't "chop", but it definitely sounds cammed. Having a free flowing exhaust helps.

All of the above, sound is absolutely the worst way to pick a cam. Overlap, when both intake and exhaust valve are open simultaneously is what you hear as choppiness. Overlap kills the dynamic compression ratio at low rpm. While it might sound good. it might not get out of it's own way as good as it does now. Low 220's duration @ .050 will still pretty much idle like a stocker when tuned right and can still give you a broad torque curve that you need in a truck.

you can get a cam with plenty of lift, but be very careful with the duration in order for it to get along with the computer.. just light porting and polishing of the heads intake and throttle body, then setting your timing a little advanced, can make these engines wake up quite a bit. set your lifter preload to around 3/4 turn . get you some good ignition wires and cap.. I like the Belkin blue wires.

sntrym said:

If you use the stock cam they are fine, but almost any air/fuel upgrade along the way is likely going to require other upgrades like a better flowing head. I was able to get around 300hp and 400ft/lbs with the setup I put on, yet still get 16-17mpg at 60-65mph.

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YEP they rarely crack, or warp. they work great for what they were designed,, a real workhorse, hauling, towing boats and trailers, hill climbing, steady power to power thru mud in 4x4..
Im building a 98 with the roller cam, and putting the 191 heads on it,.. people say im crazy, why not put vortec heads on it,, because they are prone to cracking and aftermarket vortecs style heads are expensive.. I can live without an extra 30 hp. headjobs arent cheap.. lol

All of you have good points about the TBI heads. Personally, I don't run them and run the Vortecs instead. I've got a ported set of Vortecs that work GREAT on my 406 sbc and I made dang sure to put a good cooling system in the truck so they don't get a chance to heat up much. I've been running Vortecs for the past 6 years now and have yet to replace any. True, you've gotta be careful with them as far as temperature goes but you just can't beat the bang for the buck.

If you are going to run the TBI heads and you're still running the TBI unit, whatever cam you get just make sure it's one that makes power from idle to 4500 rpm and with an LSA of around 112-114 degrees and you'll be alright.

texas tough said:

YEP they rarely crack, or warp. they work great for what they were designed,, a real workhorse, hauling, towing boats and trailers, hill climbing, steady power to power thru mud in 4x4..
Im building a 98 with the roller cam, and putting the 191 heads on it,.. people say im crazy, why not put vortec heads on it,, because they are prone to cracking and aftermarket vortecs style heads are expensive.. I can live without an extra 30 hp. headjobs arent cheap.. lol

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agree

I appreciate everyone's response. I've been busy lately so haven't been on much.

@Supercharged111 probably said it best on what I'm after, since I don't know much about cam profiles. I do want a more aggressive idle, but more importantly I need more torque at lower rpms to get the truck moving easier, since it has a 4" lift and 33"(?) tires.

I've been doing some research and learned that most likely no matter what I go with, I'll have to replaced the valve springs and advance the timing. Now it's just a matter of finding what sort of duration will work with the TBI heads.

So whats the difference between advertised and actual duration?

I have two kits from Comp cams I've been looking at.
#1 Everything in this kit should work with very little modification.

#2 And this one, I check most of the boxes. I have headers; 3.73 gears; and 2400-ish converter stall. Although this one has a higher rpm range then #1. This one says it requires headers. I do have a pair, but they are intended for my C1500. So how would this affect the performance if I used the stock manifolds? https://www.compcams.com/xtreme-4x4-220-224-hydraulic-roller-k-kit-for-oe-roller-sbc.html

Schurkey said:

Choppy idle means misfire.

Misfire means reduced power, increased fuel consumption, and Death To Catalyst(s).

You will not pass emissions testing.

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I live in Arkansas; no emissions testing. And the truck does not have catalytic converts(previous owner).

Just a question here, you're looking at oe roller cams, it's been my experience not all tbi blocks are roller ready. I may have missed where you verfied yours is??? if not roller ready need to be looking at retro-fit kits.

Hipster said:

Just a question here, you're looking at oe roller cams, it's been my experience not all tbi blocks are roller ready. I may have missed where you verfied yours is??? if not roller ready need to be looking at retro-fit kits.

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The engine that was originally in it had a roller cam. It ate several main and rod bearings. The block was barely salvageable so I grabbed a block out of a 96 pickup. The cam is okay but has several minor grooves in some of the cam journals so I'm going to replace it.