is my 350 underpowered for my C20?

[cleansquare]

First let me start off by saying I realize its a 3/4 ton truck. I realize its heavy.

My 350 was completely rebuilt by me about 4 years ago. Everything was new internally and externally. Only thing I added different from stock was flat top pistons. This last august I added vortec heads, and a summit k1102 cam, advertised numbers are 278/288, .421/.444. But actual duration at .050 lift is like 204/214. When I did the heads and cam and intake I put new dist cap amd rotor, plugs and wires...etc. always run synthetic in engine and never uses oil...I did a compression test on it BEFORE the heads and here are the results... (a few I didn't do)




Cam link:
http://m.summitracing.com/parts/sum-k1102


The truck is running a quadrajet that was never really tuned for the difference in cam or heads. 1" carb spacer, long tube headers and no cats, duals out to flowmaster super 44's and turndowns. 4.10 gear, stock size tires. 235/85/16.

The trans is a 4L80e I added a year ago. Stock sized converter supplied by the trans guy. At this point I'm finally trying to work out the kinks of the computer system...the ez tcu I'm running from tci. Having issues with the tps sensor and issues like extreme strong 1-2 shift, no downshifting and tq converter not locking up, but I think thats due to my trans oil temp staying low cause of the huge cooler up front and the fact that its below 30 today. I am in contact eith tci and am about to go ohm out that tps sensor.

The truck is not exactly sluggish but doesnt have a.ton of extra powerleft besides accelerating power. Takes a while to get up there but can run 85 all day. I just feel like for a 350 with vortec heads it should be a little peppy-er.


Here is a plug I just pulled a minute ago.





Video of exhaust

[geezer#99]

First thing comes to my mind is timing.
What's your initial set at?

[cleansquare]

Originally Posted by geezer#99

First thing comes to my mind is timing.
What's your initial set at?

To be honest geezer I don't remember its something I'd have to check.

Bt good news...I think I solved 90% of my problem. This tcu uses a carb mounted tps signal, it can't be less than .1V at idle and more than 4.9V WOT. Well, I never could get mine right and been driving it almost a year with neck snapping shifts, no downshifting at WOT, and trans shifting thru all 4 gears by 35 mph.

No wonder my 350 felt like a turd. It had to accelerate to 70 in overdrive from 35 mph and wasn't using any of gears 1, 2 or 3 for acceleration, just going right thru them.

Once the tps was set correctly with a voltmeter, I was able to get out the manual and go thru all the settings and change them to my liking while driving on the backroads. And since the tps was right it actually worked.

I moved my line pressure down and now the truck shifte lime a.cadillac unless I get on it.

I moved my max shift speed up to around 4200rpms and now when I punch it the truck downshifts and scoots! It was set at 2500 rpm, so as soon as it downshifted into 3rd, it hit the 2500 mark and shifted back Into 4th. That's why it never worked.

Also, the truck now carries shift points way further out, providing MUCH better acceleration. Right now its shifting into OD at about 55mph, but I can bring it even further if I want to.

As lf this moment I am VERY happy with this truck. Lol I can believe I waited almost a year to finally call tci and make then help me!

[geezer#99]

Sounds like you found the cure!!
Drive it like you stole it!!

[meatwagon83]

that will probably help your fuel consumption problem as well