[TOORUDEFORU]

Lookin for a little help, got a few questions that I can't seem to get answers, even from GM.
I have a ZZ383 in a 84 Elcamino, been running it for over a year now. I think it's time to add a little bit more to it. I been thinking about swapping to the next bigger cam the general has to offer, witch is the biggest they have(#12370847) hydraulic roller, my engine came with the 12370846 hr. I don't see a problem withe that, but what will it do to my HP & TQ.
I also have a couple of set's of 1.6 rockers i'd like to install to add a little more pop to it. The motor came with 9 to 1 pistons, are these dish pistons, am i going to have to rip it down and clay the pistons to check for clearance. just so you know this engine came with the fast burn heads.
any body got a clue or suggestions
thanks
Rick

[383silverado]

Originally Posted by TOORUDEFORU

(#12370847) hydraulic roller,

my engine came with the 12370846 hr. Rick

first off we are talking about 62cc heads right

12370847
This hydraulic roller design contains eccentric for mechanical fuel pump. It is for off-road use only. The duration at .050" tappet lift (intake/exhaust) is 234/242; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 539/558. Valve lash is zero/zero and lobe centerline is 112 degrees.


12370846

This hydraulic roller design contains eccentric for mechanical fuel pump. It is for off-road use only. The duration at .050" tappet lift (intake/exhaust) is 222/230; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 509/528. Valve lash is zero/zero and lobe centerline is 112 degrees.


just so every one knows what we're working with.

[TOORUDEFORU]

Hey there 383silverado
Thanks for the info input, and YES they are the 62cc (aluminum) heads
Rick

[383silverado]

what are you looking for top end bottom end ?

214 intake duration @ .050 for bottom end power 215+ for top end

what stall are you running?

if stock your best bet would be to start there.

[TOORUDEFORU]

2000 stall for now, just to keep it low in the powerband

[383silverado]

scroll down to camshaft characteristics

http://www.fierolt1.com/lt1_camdata.htm

[TOORUDEFORU]

reason for the 2000 stall was to keep the rpm down on th highway , I just put a built 700r4 this year. (old style tv cable shift with a non lockup converter) (3.08 posi rear) to try and get some low rpm cruising. Why are they listing the 47 cam twice on the cam link ? would it benifit me to just change the rockers from 1.5 to 1.6. these rockers came from a 96 LT4

[383silverado]

why not go with a set of 3.73 gears that would really help or 4.10 since you do have an over drive trans.

[techinspector1]

I predict the truck will be slower with the bigger cam. That cam needs 10.00:1 to 11.50:1 static compression ratio to work correctly and you ain't got it.

The intake valve is gonna close later and not trap enough mixture to increase performance. Just my opinion.

[Arcuden]

If the heads have 62cc chambers, then your 9:1 pistons are definitely dished. You should be able to install the 1.6 ratio rockers and not have to worry about piston to valve clearance.

[383silverado]

i agree but at this point all his power now lies in the gearing not in top end.

383 222/230 @ .050 509/528 lift 112 lsa + 3.08 gears =

383 222/230 @ .050 509/528 lift 112 lsa + 3.73 or 4.10=

[solidaxel]

My .$.02 Change the gear and run the engine hard with the set up you have !!!

[TOORUDEFORU]

Thanks for all the advice guys. i've thought about it and been told about the gears time after time, i guess it's time to get off my butt and wallet and order a set. It's funny how some of us don't wanna cross that one line, but we'll piss away all kinds of money on alot other BS. 373s here I come.
thanks
Rick

[383silverado]

you won't be disappointed my friend .

[TOORUDEFORU]

just thought you would like to know, this is all going on with a 84 ELcamino ss