quick easy-ish 350 upgrades

[spenser21]

can we bring this back alive to talk about what cam to throw in?

 

[MikeB]

We need to know compression ratio and axle ratio, and how you intend to use the truck. Some aftermarket cams can add more TQ and HP with little or no loss of low RPM manners and throttle response, but others can ruin a good truck.

Just noticed that you have 33" tires, so your axle ratio will be really important for cam selection. Crane Cams has always used RPM @ cruising speed to determine which cam works best. For example, if your engine is turning 2000-2300 RPM at 60-70 mph, you wouldn't want a cam with a 2500-6000 RPM powerband.

 

[rich weyand]

If you google my last name with 12-300-4 and 12-235-2, you get lots of cam discussions.

Look at google response 1,2,3, and 6:
https://www.google.com/#q=weyand+12-300-4+12-235-2

 

[spenser21]

so not sure about the compression ratio, its a stock 350 if that helps any. the gear ratio I can figure out on my lunch break in about an hour. I don't have a tach in there just yet so that whole cruising speed thing could be tricky. im more just looking for some torque to get me from stop light to stop light faster.

 

[spenser21]

ALSO... just so were all on the same page, I can change fluid and brakes. this will be, by far, the most in depth thing ive ever done and will be watching a lot of videos and reading a bunch. so ya basically no idea what im doing

 

[1973c10]

ALSO... just so were all on the same page, I can change fluid and brakes. this will be, by far, the most in depth thing ive ever done and will be watching a lot of videos and reading a bunch. so ya basically no idea what im doing

Just take your time and it will come together,
you are already on the right track by doing your research first
and remember we all started out
basically having no idea what we where doing

 

[spenser21]

Just take your time and it will come together,
you are already on the right track by doing your research first
and remember we all started out
basically having no idea what we where doing

I appreciate that... itll be a fun process and hopefully I learn a thing or two...

so I think ive decided on the 12-235-2 cam. been a long day with lots of reading. I did read that its a good idea to replace the lifters and timing gears and possibly push rods at this time as well? any input on that would be awesome! thanks again for all the help guys

 

[rich weyand]

Well, there's several levels of utility there:
You M-U-S-T replace the lifters when replacing the cam.
You should replace the springs when putting in a 12-235-2.
It's probably best to put new oil seals in it while you have it apart.
It's a good idea to replace the timing set while you have it apart.
Replacing pushrods is simple and cheap, why not?

Use the correct Comp Cams springs for the 12-235-2. It's higher lift than stock, so you want more spring pressure so you don't float the valves.

The 12-235-2 is a good choice for your goals. I think you'll be happy with it.

 

[spenser21]

Well, there's several levels of utility there:
You M-U-S-T replace the lifters when replacing the cam.
You should replace the springs when putting in a 12-235-2.
It's probably best to put new oil seals in it while you have it apart.
It's a good idea to replace the timing set while you have it apart.
Replacing pushrods is simple and cheap, why not?

Use the correct Comp Cams springs for the 12-235-2. It's higher lift than stock, so you want more spring pressure so you don't float the valves.

The 12-235-2 is a good choice for your goals. I think you'll be happy with it.

that all sounds good to me. I hate doing things twice, so if I can kill two birds with one stone while its apart, im all for that!
but....
after all my reading yesterday I ran across this as I got home.

sum-k1103

if I understand what im reading this is "almost" the exact same cam but should have a little more lopey sound, and comes with lifters, and saves the bank a bit.... im all for cheaper, but I don't want to tear this thing apart in a couple months if this is garbage.

 

[rich weyand]

First, a "lope" means the engine is uncomfortable running at idle. So how much torque are you going to have at 1000-3000 rpm? A lope in a V-8 is the natural result of being cammed for horsepower at 5000 rpm and above. How often do you drive at 5000 rpm? If you're a racer, ALL of your driving is at 5000+ rpm. That's why racers have a lope. A street-cammed engine for driving will idle smooth as silk, and come on hard with tons of torque from the get-go, because it likes running in the low rpm range.

The Summit K-1100 series cams are old-school grinds with 70-75 degree ramps. The transition time on a valve is basically wasted time. The valve is too closed for good flow, but too open for compression or power delivery. The Comp Cams grinds are 40-45 degree ramps, designed by a computer so they don't hammer the valves. That allows the valve to go from "flowing" to "closed" that much faster, and generating more power, more torque, and better mileage all at once.

To illustrate:

flowing.......ramping......compressing
XXXXXX-------70*-------XXXXXX
XXXXXXXXX---40*---XXXXXXXXX

Don't get me wrong. The Summit cams are better than stock, and a lot of people are happy with them, but they're not as good as a modern grind.

Remember, you only get what you pay for, and sometimes less.

 

[spenser21]

that's the answer that I was looking for I guess. like I said I don't want to waste time or money if I can spend a little extra and get something that's going to be a better investment

 

[MikeB]

Next step is to do a lot of reading and/or watch videos on changing the valve springs. There are ways to do it with the heads still on the engine, but it can be tricky. Sometimes I think the old "rope in the spark plug hole" is the most effective. I've done many using compressed air, but have to admit the last time I did it, I almost let a valve drop into the cylinder.

Also, does the engine run well now? The last thing you want to do is modify an engine that has internal problems. It's probably a good time do a compression test. Again, you can find the correct procedures online. Adding more intake duration to an engine with marginal compression will reduce low-mid RPM cylinder pressure, which can kill torque.

 

[MikeB]

First, a "lope" means the engine is uncomfortable running at idle. So how much torque are you going to have at 1000-3000 rpm? A lope in a V-8 is the natural result of being cammed for horsepower at 5000 rpm and above. How often do you drive at 5000 rpm? If you're a racer, ALL of your driving is at 5000+ rpm. That's why racers have a lope. A street-cammed engine for driving will idle smooth as silk, and come on hard with tons of torque from the get-go, because it likes running in the low rpm range.

This should be a sticky!

 

[spenser21]

not sure if that's something I can do or not...if so, I don't know how lol

 

[rich weyand]

This should be a sticky!

Yeah, I have to say it so often that I've thought of putting it on a function key.

"I'd really like a little lope."

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