New Cam Install

[383ss]

That's strange... What make is that cam, 383?  Lunati or MTI? What LSA?  What other mods do you have?  (converter, tuning, etc)

 

How much do you tow?  What area do you live in?

 

I am interested in going up in duration for more top-end power, but I absolutely don't want to go back where I was with the 220/220 112.

 

One of my biggest complaints with that cam (looking back now) is the huge lack of area under the curve.  I can remember going to accelerate down a stretch of road that I drive frequently.  RPM's would be around 2,500 in 3rd, after kicking down out of 4th and OD.  I could move the throttle from ~25% to 50% with little change in speed.  It would require another kickdown to second to really get moving.  Do you find anything like that with yours?

 

I never dismissed the idea that my stick was just a crappy grind done on a Friday afternoon or if there was something else wrong with it (with all that nasty valvetrain noise I had).  I'm certain it was installed dot-to-dot and not off a tooth.

<{POST_SNAPBACK}>

it's an MTI C1 cam. 222/222 112lsa .56X lift if I remember right. should be a comp XER lobe. I tow my camaro, it's about 3200 lbs plus the open 16" trailer. I didn't notice anything like what you had with yours, but that doesn't mean it isn't that way. I live in kansas city. fairly flat.

 

I'm also running a stock stall converter and my 60' times are the same. high 2.1 to 2.2 area.

[matt rem]

Marc, I really think the 220/220 would have liked the headers. Whats up with the head ideas? I am thinking hard over here, heads or STS. There are some nice heads out there.

383 your truck would love a set of long tubes. I am with you, I don't feel the need for a stall either.

[marc_w]

That's really interesting, 383. I may be revisiting the idea of a larger cam.

 

Matt - heads - I'm BUMMED. I'm really not happy with the numbers I'd get using a 66cc head - Called up a shop, we had a good plan put together to get the 76cc heads to work - it turns out Tony @ AFR decided not to produce the 76cc heads, so I'm mildly SOL right now. ;)

[383ss]

ok, now I'm looking at dyno graphs of my cam, FIPK, tuning and ASP vs stock. they aren't on the same sheet though...

 

the both start around 3300 rpm and are about identical.

3300 modded is +5

3800 modded is +10

4200 modded is +20

4600 modded is +30.

at that point the stock graph cuts off because of the Speed limiter, assuming it peaks at about 280rwhp, (which is what it looks like it will make) the modded would be +50.

 

so you are right, this cam appears it will give up a little down low but I got that all back with pulleys, FIPK and tuning. I would guess with a set of longtubes or thorleys, I'd gain a lot all over the RPM range. it also looks like a 3000 stall would be perfect for this cam. good thing I have one in the garage ;)

[SSLink]

The real problem with dynos is that they seldom show what's going on below 3000 RPM. That may not matter much to a drag racer with a big stall but in daily driving in this heavy truck I bet when I don't get on boost to blast out onto the highway or pass I spend 90 percent of the time below 1500 RPM.

 

To get moving it helps that the stock converter stalls pretty high, but I like to have lots of torque off-idle to 2000 RPM to manage grades and lug along in 4th gear at highway speeds. It's a tradeoff against top-end but in my case I make up for that nicely with boost!

[matt rem]

I am thinking the same thing Marc, Allen is saying STS all the time and I am starting to believe in it. Heads would be nice, but finding the right combo is hard.

[marc_w]

I am thinking the same thing Marc, Allen is saying STS all the time and I am  starting to believe in it. Heads would be nice, but finding the right combo is hard.

 

All I've been reading about these last few days is stuff about the STS kits.