Cam and other advice, vortec 350

[Chris253]

So this is what I have so far, just looking for advice on what cam and rods to get: roller 350 bored 30 over, hypernuectic dished -12cc pistons (kb193.030), 9.015 deck height, stock replacement crank from summit. Modified iron vortecs for lift, 7/16 studs.

Now I was going to go with the hot cam but I've been getting mixed opinions. Not looking for anything radical, but a nice lope is nice. It'll mostly be used to drive around town, haul light loads on the highway with the occasional car hauler to pull my 280z around. Trying to button this up in the next couple of weeks hopefully. Also, carb or injection? Going into a 98 z71. Thanks

 

[Ed_P]

im staying TBI myself, if I had a manual i might go carb... and I still may. I chose comps site a few months back and their cam selection tool is very cool. Others probably have the same thing , I put in my info selected various cams and it gave back a ballpark hp/ torque rating for comparison and selection. I ended up with a 260HR for my needs. looking for 380-400 lb/ft, the dyno will tell the tale in a few weeks

 

[slowburb]

Manual or automatic transmission?

 

[shovelbill]

gearing......tire size?

 

[Chris253]

Automatic for now, 285 75 r16 and I'm not sure about the gears, probably stock at the moment but I'm not opposed to upgrading. Thanks

 

[shovelbill]

Automatic for now, 285 75 r16 and I'm not sure about the gears, probably stock at the moment but I'm not opposed to upgrading. Thanks

i'm learning about this myself....that's why i ask questions. know that your EFFECTIVE gear ratio will greatly influence a cam choice. ....or how well a cam works for the application. that factor is the same in every type of vehicle, be it a Harley, truck or track car. you're in a good position to build a very good combo in my opinion.

my '98 Z71 came with 3.42 open carrier........one reason i stayed with 265's when i bought new rubber. my combo works well for how i drive my truck, which was mostly highway......if i had 3.73's i would have went to a 285......if the truck was mostly used in the city a 33" tire and 4.10's would have been better on the stock motor..........fast forward. i needed a new engine and went with a 383 for the low end torque a stroker will provide........i've always built stroked Harley engines vs. over square motors for the street.

Mr. slowburb's build thread is very informative with info on his cam choice......i'll defer to him and others' expertise about GM truck cams......if this was a Harley i'd be your guy......but basic principles apply.

i'll see if i can rustle up some threads i saved when doing my research. i was on the fence as to hat and how to build.

 

[shovelbill]

http://www.gmt400.com/threads/slowburbs-slow-burb.31854/page-3

 

[slowburb]

It doesn't make a lot of sense to put a carburetor in this truck. Keep the factory injection setup. If you carb swapped, you'd still need the computer to control the transmission. With this in mind, it's easier to keep the induction system intact believe it or not.

With any towing intended, I'd say the hot cam is too much duration. Especially if you're not willing to install a torque converter with a higher stall rating. Especially with an oversized tire. It would be a good idea to determine the gear ratio, as there are at least three "stock" gear ratios for a 1998 half ton 4x4 pickup. If you're trying to put together a very well thought out combination, instead of a cammed motor that doesn't match your drivetrain, you'll want to know the gear ratio. The glove box RPO sticker will have listed a bunch of 3 character codes. Post the codes here that start with the letter "G".

Have you considered a torque converter upgrade? Would you?

All of this together determines the load that's put on the engine to launch and propel your truck (and whatever it is towing). This is a pretty major factor in longevity of your drivetrain, and how well it performs.

 

[shovelbill]

think of it this way.......

take a 1969 DZ302 Camaro engine......absolutely glorious engine and the POWER it made!!!....7,000 rpms! made that Z28 one superfast ***** (couple years actually)........nothing on the bottom though, high power up top........now stick that ABSOLUTELY wonderful engine in a suburban towing an RV trailer up a mountain pass........ALL WRONG.............understand?

go research a 421SD Pontiac engine...........WHOA.....i had one in my '63 Grand Prix.

 

[Supercharged111]

think of it this way.......

take a 1969 DZ302 Camaro engine......absolutely glorious engine and the POWER it made!!!....7,000 rpms! made that Z28 one superfast ***** (couple years actually)........nothing on the bottom though, high power up top........now stick that ABSOLUTELY wonderful engine in a suburban towing an RV trailer up a mountain pass........ALL WRONG.............understand?

go research a 421SD Pontiac engine...........WHOA.....i had one in my '63 Grand Prix.

I bet that Burb would pull great up a mountain in 1st gear