would it be ok to go with a nice new set of 1.6 rockers on my otherwise stock l03?

i would need the 3/8" stud correct?

and they should just bolt on?


how much gain would i feel for the 200 dollar sum it would cost me?

 

How worn are your stock valve springs. 1.6 rr's on a LO3's have been proven to reduce et's by .2 and gain 1mph. The stock LO3 cam needs all the help it can get. For most stock cars the money could be spend elsewhere but on LO3's they work suprisingly well.

 

Im sure they come in either 3/8 or 7/16 stud sizes

increasing the rocker ratio is the cheap way of boosting the cams lift and duration, without actually changing the cam itself.

do a search. This has been talked about before.

*edit* yes, what about your valve springs. is there enough clearance for the added lift? amongst a few other things...

 

im not sure, kinda why im asking, will they fit under my stock valve covers?

im not too familiar with rocker arms.. what all would i need to check to make sure they work?

 

If you run the stock cam you will not exceed the max lift of the heads. You need a narrow body style rocker to clear the valve covers. Look at the basic roller magnum/steel style rockers out there. The "big boxy aluminum" ones aren't the best if your LO3 is otherwise stock.

 

<A HREF="http://store.summitracing.com/partdetail.asp?part=CCA%2D1418%2D16">CCA-1418-16</A>

 

hye thanks for looking that up man.

and what is the stock lift on these heads anyways?

 

You do not want to go past .480. I would play it safe and not go past .460. Head casting differences throughout the years change the tolerances a bit.

 

and iheard the 1.6's raise the lift theoreticlly about .030 is that correct?

 

take your lift now, example .400/1.5 = .266 take that and multiply by 1.6 and you get .426, thats the new lift.

You would have .373 intake lift, and .410 exhaust.

 

cool im looking at a .458 lift

its gonna be close, but safe.


cant wait someday for new heads and cam,

with the rockers, i will have a .535 lift. is that too extreme? the heads im looking at support a .560 lift.

(this is exhaust lift, being the bigger number of the two)

 

Ok nevermind you said you had an 89 tbi 5 speed

your lift would be .443 intake, and .459 ex.

 

No that is not too extreme. Thats about right for a decent performance cam.

 

All 305 tbi's got the peanut cam, which comes to .350/.385 with the stock 1.5 rockers. He would have 373/410 lift with 1.6 rr's. I've heard from numerous sources that this will be fine on stock valve springs, but I am still wanting hard facts on what they can actually take.

 

At like 85 lbs of seat pressure, they dont take much of anything. Valve float is a PITA.

 

ive looked at bigger cams, but they say u need a stall converter..

this is the biggest i can go i feel.

http://www.jegs.com/cgi-bin/ncommerc...96&prmenbr=361
part # 249-08-422-8

Grind: 270
Lift: .495''/.502''
RPM Range: 1600-5400

theirs the cam right under it

Lift: .510''/.520''
RPM Range: 2200-5800

but i dont kow about that rpm range.. my idle will kill me.

and the intake manifold im looking at only pulls to 5500 so that extra 300 are gonna be wasted.

 

thats the cam with the automatic tranny, ive got the rare 5 speed which has a cam with .415/.430

 

not on tbi cars, they all got the peanut cam regardless of which transmission you have.

 

Don't the L98 and the L03 both have the same exact valve springs? So if the L98 has .428 lift the valve springs shoud be fine for a stock cammed L03 with 1.6 rr's I would think.

 

are u serious? that makes me mad. thirdgen tech data should note that.

where is this info found? so i can see it for myself.

 

Only the g92 5 speed 305's got the bigger cam. There were no G92 tbi cars.

 

is this noted anywhere in the rpo codes?

 

25THRSS is correct on everything above. Although not certain, I am pretty sure the valve springs were different between the LO3 and L98. Some other points to make.
-You do not need a stall converter since you have a T5.
-You have about the smallest cam out there ever put into a small block.
-Your LO3 cam is no different than any other 305 TBI cam out there.
-There was no G92 or equivalent performace upgrade for TBI cars

 

how will my idle be if i had this cam with a

Grind: 82
Lift: .510''/.520''
RPM Range: 2200-5800

?

does rpm range mean the optimal operating range?

 

I was going by my gm manual which lists the specs for each v8 engine that year and it lists the valves springs as being the same.

 

Hey good to know. One more reason why the Lo3 is not a complete waste

TaviZ

What is the LSA and duration on that cam? What heads were you going to use them with again? This may need to be moved into the TBI board.

 

OMG thank you thank you you made my day

 

Time to add to your tool kit.
Buy a degree wheel and a dial indicator. then instead of asking what your cam specs are, you can tell us.
A degree wheel and dial gauge are two tools you'll never have regrets about buying, you'll use them over and over again. While you're shopping, get a TDC locator too.