350 motor build need help and opinions

[severon]

Hey guys as the title says I'm building a truck and need some advice but to start here's more about the truck

Its a 1982 GMC high sierra 4x4 was originally a 6.2 diesel and when I purchased the truck it came with a older 350 small block unsure of year I have installed a holley 750 3310-3  vacuum secondary carb with a Mr gasket 1 inch spacer plate with a edelbrock rpm performer air gap 4 inch hi rise intake with headman I believe 1 5/8 to 3 inch outlet long tube headers it has I believe stock 462624 casting number heads with 1.96/1.5 or 2.02/1.6 valves I believe it has the 2.02 valves from running the date code and casting numbers I believe the block is also stock it has gm corporate 10 bolt front end and gm corporate 12 bolt rear end with 3.42 gears a th350 transmission stock torque converter with a older 203 gear driven transfer case with a part time 4x4 kit installed with dual 2 1/4 straight pipe exhaust installed that dumps out behind the rear wheels it has 36x13.50x15 super swamper irons on 15x12 outlaw 2 wheels

Now my question is I am buying a crane cam for 30 bucks with 240 duration and 350 lift with my current setup I'm told I can install this cam without changing my lifters or rockers or valve springs is this true? And is this a good cam for my setup? And what are your thoughts on a trans go shift improver kit?

I am using this truck for street use occasional off road use and very rare light towing and hauling and just fun to drive, I am trying to build a 400 HP 400lb tq 350 small block that has a constant power curve from 1000 rpm to just under 6000 rpm

Thanks in advanced for any advice and input and sorry for the mile long post

[VileZambonie]

You've got some broad goals there. So is this a new cam? Give the specifics on the cam grind. What pistons are in it? Are you planning on rebuilding it or just putting a cam in it?

[Stewart G Griffin]

1) First i hear a lot of good things about the performer rpm air gap and regular performer rpm intakes.

2) i AM NOT an engine person, so i'm just putting out my opinions here:

The cam might be a little iffy as far as driveability----idle and low rpm driving.  At the very least you might need a looser converter.  If you had a stick you can get away with more cam.   This is just my opinion and maybe the cam might be great for the combo.

i too am curious whether you can use a new cam with used lifters?

3) i've driven cars with the b+m shift improver kit---in heavy duty/race mode.  Shifts too hard for street in my opinion.  If you can get a kit that dials in a more street or street/strip kind of mode i think it would be better.

[75gmck25]

If that cam is 240 at .050 its much too big for your engine.  Most RV cams used with these low compression 350's are not more than about 214-218 @ .050.  You may get by with up to about 222 @ .050 (its used in the GM 350/290 hp crate engine), but it won't have the bottom end you need in a heavy truck.

Bruce

[severon]

To answer some more questions the pistons in the truck are stock I'm running 76cc chambers on my heads and the cam is used it had a break in period before it made 6 passes at the strip I purchased it today for 30 bucks figured worse case I sell it if I can't use it, the cam came out of a stock 350 with stock lifters and valve springs the only numbers I can find on the end of the cam are cch-342-nc than below that it says crane and below that is 4 199 and below that is 11-11-85 from what I can find is a old build sheet with a similar cch# that states the cam is 254/254 lift with 324/324 duration with 108 center lobe line but I do not know if these specs are true. Is this something I could go ahead and install or is this a race only cam? Not to worried about a awesome idle or sound as I am the all around performance

I eventually plan to bore this block to a 355 with forged pistons forged rods steel crank with one piece main and aluminum 215 cc 60cc chamber 2.02 valves heads but I'm having to do all this pieces at a time with a wife and two kids lol

[severon]

Also Stewart g griffin after doing g some more research trans go offers a shift improver kit specifically designed to tighten up shifting for street use light towing and a longer transmission life guranteeing no slamming when shifting which is only 37.99 I am going to install this weekend will let you know more in a week or two if the weather breaks enough to work on the truck been too cold here in Kansas to do much

[severon]

hey guys sorry to trouble you again but i found a new cam instead of that big monster racing cam i picked up i am actually trading it for this cam heres the specs let me know what you guys think of it

I am trading for a gm performance cam P/N 24502476
Flat tappet with matching lifters
.435" Int./.460" Exh. lift
212 Int./222 Exh. Duration @.050"
112.5 Lobe Centerline

(Only info i can find online besides what the guy sent me up above)
This hydraulic flat tappet is used on the 350-300 and 330 HP special performance engine P/N 12355345, and 12486014. The duration at lash point in degrees (intake/exhaust) is 320/324; duration at .050" tappet lift (intake/exhaust) is 212/222 and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 435/460. Valve lash is zero/zero and lobe centerline is 112.5 degrees.

What rpm range will this cam give me? Am i gonna be able to run it with stock valve springs in my setup and can it still be used for street, light off road, light towing, and fun cruising?

[dvdswan]

as good as it sounds, a cam for $30 is iffy.  IMO, I would not buy a used cam because there are too many unsee possibilities.  it could have a bad lobe, it could be a stock cam, it could be anything.  when buying engine parts you need to be careful, see it being pulled out of a running engine proves its good.

I would personnally spend the extra cash to get a new one.