Best cam for Vortec in a K2500
 

I recently bought a 93 GMC 3/4 ton 4x4 with a blown 350. I swsapped a 97 Vortec into it, mainly because I already had the engine (used with 70k miles). My brother gave me an LT4 (not LT4 Hot, just LT4) cam that he bought for his 94 Impala SS but never installed. I installed this cam along with Comp Cams beehive springs, Crane 1.6 roller rockers, Crusader TBI to Vortec intake, custom chip, headers, bored TBI, etc.

Long story short, I spun three of five main bearings plling my travel trailer (only a 21 footer). I think I over revved it, as it didnt make mch power.

I now have a rebuilt 350 Vortec short block to put in it, and have to decide about going with the LT4 Cam, stock Vortec cam (L31?) or aftermarket... I ned a torque cam. THe LT4 cam didnt seem to have much torque, but I never drove the truck with the stock 350 TBI, so I have no bass for comparison...

Brian at TBIchips.com that sold me the custon chip said that the LT4 cam was the best torque cam ...???

Re: Best cam for Vortec in a K2500
 

I don't remember the specs on the LT4 cam, but I really like the cam that GM used in the Ram Jet 350 and the HT383. It's the same cam but in the Ram Jet they used 1.6 rockers. I've had experience with this cam in a 355, flat tops, Vortec heads and 1.5 rockers and IMO it had good low to mid range torque. You can often times pick up this cam on ebay as new take outs for ~$80. I don't remember the entire part number for the cam but the last 4 digits are 7395

Re: Best cam for Vortec in a K2500
 

I'd strongly consider a "4x4" type aftermarket hydraulic roller, something like the CompCams X4258HR.

LT4 (12551142) cam specs are .476/.480 w/1.6 rockers, 203/210 duration and 115 LCA. I would not consider that a "torque" cam.

Part Number for the cam referenced above is "14097395" - .431/.451 lift w/1.5 rockers, 196/206 duration and 109 LCA.

Re: Best cam for Vortec in a K2500
 

That's kinda what I thought... I wanted to et some more input before sticking the LT4 cam into this rebuilt short block that I am putting in this weekend. I should have trusted my instinct that anything originally made for a Corvette wasn't right for a big 4x4 truck...I will look into another cam. Anyone looking for an LT4 cam with around 1k miles on it?

Re: Best cam for Vortec in a K2500
 

I thought I double checked this before, but does anyone know if the TBI manual trans flywheel is the same a a Vortec manual trans flywheel?

Re: Best cam for Vortec in a K2500
 

I get what I think is conflicting info. The '98 engine originally had an auto trans attached. When I swapped it, into the '93, I had the 93 flywheel resurfaced, installed a thrust bushin in the crank and installed all of it with a new clutch, throwout bearing and pressure plate for a 93 truck, since it still has the 93 NV4500 5 speed trans. it all seemed to work OK, and I never noticed any vibration or anything...When I got to the Autozone site and look up a flywheel for a 98 K2500 manual trans flywheel and a 93 K2500 manual trans flywheel, they are the same part #. When i go t O'Reilly's, I get two choices for each year, one of the two choices is the same part number for both, the other is not. The 98 listing mentions a NV3500, the 93 doesn't. They show to have both part numbers in stock, so I plan to call them to make sure they do and go take a look when they open. My brother is bringing the rebuilt short block and I am going to try and get it set in the truck while I have help.

Re: Best cam for Vortec in a K2500
 

Advance Auto Parts shows two different part numbers for a 98 and a 93...hmmm

Re: Best cam for Vortec in a K2500
 

OK.. after further investigation, it appears that the flywheels interchange. I am still up for anone's suggestions on cams, though. I am researching the Comp Cam mentioned above

Re: Best cam for Vortec in a K2500
 

After some checking, I pulled the trigger on the Comp Cams X4258HR. Got it at Summit for $265. (Still an Ouch) At least I get 90 days no interest to pay for it on the Summit Speed card. Thanks to everyone for the advice. I saved a little by checking out my current roller lifters and plan to reuse them. I already have Comp Cams "beehive" springs in the vortec heads.

Re: Best cam for Vortec in a K2500
 

Here's another good one: COMP Cams 08-408-8

Re: Best cam for Vortec in a K2500
 

08-408-8 (part number) = XR258HR (grind number) :)

Re: Best cam for Vortec in a K2500
 

Cool; let us know how it goes! I've installed a few of these in otherwise stock trucks and the owners have been very happy. I'm 100% sure you'll like it better than the LT4 cam!

Re: Best cam for Vortec in a K2500
 

Doh. :lol: That is a good cam. Got great torque numbers in Desktop Dyno.

Re: Best cam for Vortec in a K2500
 

I believe that XR258HR is a retrofit roller. My engine is OEM roller...

Re: Best cam for Vortec in a K2500
 

Nope; my bad for posting the grind # instead of P/N: retrofit is 12-408-8.

XTREME Energy™ 1987-1998 305-350 Originally Equipped With Hydraulic Roller Camshaft, Except LT1 and LT4.

http://www.compcams.com/Cam_Specs/Ca...?csid=185&sb=2

Re: Best cam for Vortec in a K2500
 

I already have a set of Crane 1.6 full roller rockers on the engine now. I wonder if I should keep them or go back to 1.5 ratio...

Re: Best cam for Vortec in a K2500
 

Keep the 1.6 as long as the total lift is within what your springs can handle.

Re: Best cam for Vortec in a K2500
 

I believe that WIDESIDE72 bought the X4258HR pn. 08-409-8 which has different specs than the XR258HR pn. 08-408-8. I mention this since the different cam will net different max valve lift with the 1.6 rockers. This may be a factor when checking spring and retainer clearences.

http://www.compcams.com/Cam_Specs/Ca...?csid=197&sb=2

Re: Best cam for Vortec in a K2500
 

I'm glad it's your day to watch me (re: other thread :))

The 08-409-8 is the right pick as it has a bit more advance ground in to move the power peaks lower in the RPM range.

My complete bad here, guys - I just read and typed too quick and didn't double-check. :waah:

Re: Best cam for Vortec in a K2500
 

I really wasn't tryin ta pick on ya......really. :)

Re: Best cam for Vortec in a K2500
 

No worries at all - I'm glad you caught it!

Re: Best cam for Vortec in a K2500
 

where do you get the crusader tbi to intake form?

Re: Best cam for Vortec in a K2500
 

It was an EBAY buy from Mississippi... Originally a a marine app. No EGR. Scored it for $100 (!), I believe about a third of a GMPP intake. I was planning on this swap for a while was watchin feebay for it or comparable. "Even a blind hog can find an acorn once in a while." :)

Re: Best cam for Vortec in a K2500
 

Got the Comp Cam from Summit the day before Thanksgiving,but was gone til Sunday after Thanksgiving. I got the cam slipped in, but work has stalled as all I have is a shade tree for cover. It's predicted to snow in Austin area and has been in the 40's all week during the day.

Re: Best cam for Vortec in a K2500
 

...or to clean out all the junk I have accumulated in my barn. There was ICE outside this AM. It was actually colder last weekend, due to the wind. At least is was still this AM. I had to leave the motor hanging from the A-Frame, as my brother and I ran out of daylight last weekend, as I also had a Ford (Argh)tractor to work on while I had help. I wrapped plastic through the engine tilter/ lifter, then wrapped a tarp around the whole engine. I just had the pan on with a couple of bolts since the cam I bought hadn't come up yet. I pulled it to double check that I had tightend the oil pump bolt, and there was a big chunk of ice around the pump, from rain water that got in! I chipped it off before it occurred to me to take a pic. I got it cleaned up. Luckily since the cam wasn't in yet, the rockers and push rods weren't in either, so no valves were open to let water into the cylinders. My buddy and I got the engine set in and the engine well tarped for the night.

Re: Best cam for Vortec in a K2500
 

Pic of the new "shop" dog, Zoe, the ferocious killer pit bull. Notice the "bark" in the foreground. It is not hers. Hers is bigger, but worse than her bite.:lol:

Re: Best cam for Vortec in a K2500
 

Notice the lead wrapped around the A frame pole. I don't normally have a dog on a lead like this, just when i am working outside. I never leave one on a lead unattended. She is inside at night and has about a half acre pen, house with heat lamp during the day. About the time I noticed it was wrapped, I was going to unwrap it for her, when she walked back the opposite direction, unwrapping it herself. I thought it was a coincidence, so I walked her around it again, then walked away. She then walked the opposite direction again, unwrapping it. Probably one of the smartest dogs I have ever had. Or all of my previous dogs were retards (?) HAHA

Re: Best cam for Vortec in a K2500
 

On a somewhat related topic, I am selling the LT4 roller cam ($100) two stock Vortec roller cams ($50 each), barely used Mellings high volume oil pump ($20), and a new stock single roller timing set. If anyone is interested, let me know here, no PMs. I will also be putting them on the parts board. From what I understand, the Vortec cam is a good cheap upgrade to the stock TBI cam. It is almost the same specs as an LT1 cam.

Re: Best cam for Vortec in a K2500
 

It wasn't that cold (according to the thermometer, at least), but it was very damp and nasty, so I didn't get outside til about 10 am. I got the motor mount bolts tight, tranny mount bolts tight, lifters, push rods rockers spider and rocker arms on, intake torqued down today. My wife Becky came home from grocery shopping and I took a break since she made me a grilled cheese sandwich and warm Tomato and Basil Soup, hot cup of coffee and a scone (looked like a biscuit to me HAHA). She came out and helped me get the hood on to keep the weather out. ( Being married definitely has it's perks, if you find the right one, fellas). I got a few other odds and ends done before the sun started setting and it started getting cold again.

Re: Best cam for Vortec in a K2500
 

I don't remember breaking that bolt off in the driver side head, but it shouldn't be too hard to get out. No EZ-OUTs for this boy. Left hand drill bits every time. and heat if necessary.

Re: Best cam for Vortec in a K2500
 

I got the truck running a while back, but have a cel for a map sensor and engine temp sensor, so i havent driven it. I checked manifold vacuum and it is 22 psi. (needs 16 min) so i ordered a new map sensor the other day, waiting for it to come in. Not sure what is up with the temp sensor

Re: Best cam for Vortec in a K2500
 

make shure that you get the ground wires on the back of the head all grounded good ! those are for the sensors and will set map sensor and tps and all sorts of codes.

Re: Best cam for Vortec in a K2500
 

Wideside72, I'm curious as to the difference you felt in the cam swap between the LT-4 cam and the CompCams X4358HR?

Re: Best cam for Vortec in a K2500
 

The Comp cam has ALOT better low end torque. LT$ was a bad move in a big heavy 3/4 ton 4x4.

Re: Best cam for Vortec in a K2500
 

Hey wideside what are the specs on that cam

Re: Best cam for Vortec in a K2500
 

Click on the link is post #18

Re: Best cam for Vortec in a K2500
 

Ok I just saw that link. Looks like it should be pretty torque. I am looking to get a 218/226 for my vortec . (when I get it)