Hemi Killer

iTrader: (6)

Like a broken valve spring, etc.?

Hemi Killer

iTrader: (6)

ttt...

lilbuddy1587

iTrader: (1)

Why are you asking this? You have a giant engine bay! Take your valve covers off and check for yourself?

Hemi Killer

iTrader: (6)

I'm asking because my power is dropping very quick after 5500rpms for the mods I have, 383 LS1 with F13, Patriot stage II 5.3 heads, Vengence ported 90mm F.A.S.T. intake/UMI 90mm TB.

Here is the graph, Converter was locked btw:



Futral told me in a 383 with the F13 my power should be peaking at 6200 rpms, especially since I have a ported FAST 90/90 setup. What do ya'll think?

1989GTA

Was the cam degreed when installed? What type of valve springs do you have?

12secSS

iTrader: (30)

Wow, you should be way over my results. My F13 peaked at 5900 rpms, but I don't have the flow like you do. What length pushrods did you use, your preload could be way off. You could be a tooth off as well.

Hemi Killer

iTrader: (6)

Patriot Golds. When I picked the motor up the guy that built the motor said he advanced it 4* because I was in a truck. I told him I didn't want that because the cam already had a 4* degree advance ground into it. He said it would only take a few minutes to fix because I had the Cloyes hex-adjust timing chain. He popped the cover off and lined it up to what he said was straight up.

I used the stock length pushrods (7.400") and stock MLS head gaskets. I've been told that I might have too much DCR by my tuner. He said he thinks my heads might not be supporting that much flow, considering they are stock casting 5.3s and all. I'll be done with school for month after friday, so I'll have a little bit of time to check some things. Just don't know what to check first.

1989GTA

With peak power at 5500 I was thinking maybe the cam was advanced to much. That was the reasoning behind the question. The way it noses over at 5500 that might still be the case. It does not even try to hang on to say 6000 or so.

One more question? What is your exhaust system made up of?

Hemi Killer

iTrader: (6)

1 3/4" midlength LaPole headers, 2 1/2" True Duals with cut-outs, stock cats, Dual in/out Magnaflow (w/internal X-pipe) run out the back with 4x22" crome tips.

The run in blue is through the full exhaust. The run in red is through the cut-outs.

1989GTA

I think you have a little to much restriction on your exhaust somewhere. That is quite a jump when it is uncorked.

That is not your main problem though. I would revisit the cam timing.

Louis

iTrader: (7)

No valvetrain issues there. Its a flow/degree issue and Im leaning towards the latter.

Hemi Killer

iTrader: (6)

you mean the cam & heads?

98Camarod

iTrader: (43)

If he said he just popped the cover and fixed it he didn't do ****. You still have to take off all the rockers to take the pressure off of the cam, otherwise it will break the adjustable part of the timing set.

PewterZ28

iTrader: (1)

It could be worse. At least you gained power. I went from a 346 to a 383 and lost power everywhere. Plus the 383 peaked a lot earlier. I can't say that I would recommend a 383 stroker to anyone. Way too many disappointing results I've seen over the years on this website. Below is my graph. The higher curve is the numbers my 346 H/C put out. The lower curve are the numbers after installing a 383 stroker.

White_Hawk

iTrader: (3)

I think it is a preload problem. Get an adjustable "measuring" pushrod and take a measurement. All you have to do is pop off a valve cover, unbolt a rocker or two, and go. It will probably take less than one hour. You can't know if you are OK without measuring. That cam probably has a smaller base circle than stock. Plus your heads are probably milled. You just don't know what size pushrod you should have.

-Geoff

MPHmotorsports

iTrader: (18)

Not a spring issue.
The cam could be installed off or maybe the cam was ground incorrectly. The setup should not peak that early, and even if it did should carry the power further.
Good Luck,