jester1614

iTrader: (13)

I was wondering what the stock lt1 valvetrain with the stock cam can take rpm wise.

my tune is set for a fuel cutoff of 5800 rpm and I am wondering what gains if any i could see from raising the stock redline.

GIZMO

iTrader: (8)

It would probably be a good idea to install better valve springs before you do that experiment.

AChotrod

iTrader: (17)

My 6speed ripped up to 6100. The hypertech power programmer sets it at 6200. If you use their tune on a stock LT1 F-body, I think its like 5800 for Impala/caprice

jester1614

iTrader: (13)

gizmo thanks for the advice. I am trying to figure out how high the stock springs can be spun.

and AChotrod so according to hypertechs settings it might be safe to spin my lt1 (fbody) to 6100

GIZMO

iTrader: (8)

I really don't think that there is anything to be had by over reving an automatic. I played with this a lot years ago. With a straight drive it may help to keep the motor in it's power band on the shifts. Upgrading the valve springs will give you better valve control at higher rpms which equals HP(the stock springs are pretty weak).

Torkman15

iTrader: (2)

I guess I'm curious as to the reason you would want to rev past the point the stock cam makes most torque???

Just remember this "Horsepower sells cars, torque wins races"

moehorsepower

iTrader: (3)

There is no reason to spin a stock LT1 any much higher than stock, springs or no springs, the cam combo is usually all over with by around 5500 thats why GM set the limiter to 5750..

LT1FirebirdSLP

iTrader: (2)

I have a 94 LT1/M6 and I rev to 6200. Stock Cam.... for now.

moehorsepower

iTrader: (3)

Try lowering your shift points at the track and mark where your MPH starts to fall off, this is your peak power band. if you shift at 6200 try 6100 then 6000 ect. if your times are the same then you are spinning the motor for nothing...

LM97Z

iTrader: (4)

Agreed, you can spin the engine till the cows come home & gain nothing, but most likely loose ET while in the process of wearing your bearings/rings out quicker & chance one will spin, the stick cars will see bigger rpms if wanted with a heavy flywheel, but theres no need for it if it benefits nothing, i think these stock cams fall apart at or around 6K, just like most stock cams do, with a dur. of 2.0s @ 50 ain't ****, even on a 117 LSA, just spreads out the power band, i shift mine at 5600, we know the stock heads are good to 63-6500 stock with the right cam, but the stock cams don't pull know where near there, i would stay under 6K on the shifts to keep your engine happy. Maybe someone has a Dyno pull on a stock-cammed bolt-on LT1 they can post with some #s on the peak torque on the stock cam & where is falls off, because thats where you should shift.

GIZMO

iTrader: (8)

That statement should read 73-7500 rpm.

ss.slp.ls1

iTrader: (36)

+1. Plus I read that the stock lifters bleed off at above 6K so it almost like it has a built in rev limiter (lift decreases at excessive rpm), you won't be making much power above that point.

lt1-xjs

My peak torque is @ 4200, horsepower is @ 5700 rpm, my 1-2 shift @ 6000,
2-3 shift 5800 rpm. This yields the best results for me. I do have up-graded
springs and rockers. When my car shifted @ 5500 rpm, I was running in
the 13.7x's, that was awhile ago.

LM97Z

iTrader: (4)

So your saying stock (untouched) LT1 heads will pull to 73-7500 rpm, even with the right cam, if this is true then thats pretty impressive, i don't see how though, why would anyone change these heads if this were true, be a waiste to me, i'm sure its no more then 6500 max, because thats what most are getting out of these heads in stock form, they can be overcammed fairly easy, this is just been my observation from all the post i've read in this & other sights, so show me a Dyno sheet with a BONE STOCK headed LT1 with the right cam makeing power at 7500 rpm, then i'll be a true believer , not trying to be a smart azz, just prove it to me, i know a cam will do it, but the stock heads might be saying WTF are you trying to do

LM97Z

iTrader: (4)

This sounds feesable, but what will the shift points be with stock rockers/springs, i'm sure less, we basically know that a better stable valvetrain will yeild better pull in the upper rpm power band, just not so with stock stuff most of the time, thats the 1st. TWO things you would want to change to make a smaller cam more efficient in the upper rpm range, so bottom line, thats why your making better power up there, my stock ***** done at 56-5700, & i mean done lol.

BOLO

iTrader: (40)

Back when my car had just your basic bolt ons, I played around with the shift points using the Hypertech Programmer. I remember setting them at around 6000 to 6200 rpm for best 1/4 mile times. And setting the limiter at 6400 rpm.

LM97Z

iTrader: (4)

I'm useing the hypertech also, maybe i'll play around with shift points (set them higher).

bobdec

Stock valve train numbers.. Did a couple of pulls a year ago prior to cam install, '94 A4 with CIA and CAT back only, original plugs, wires (72K miles), stock cam , springs, rockers, and exhaust manifold. Peak torque 278 at 4800 held flat till 5000 and then droped off slowly, peak HP 241 at 4000 flat to 4400 and then dropped off drastically to 190 at 5400. Have since added tune, new plugs, wires, a mild street cam, 1.6 RR's , springs and 3.42 rear. Waiting for headers and 2500 stall installation prior to next dyno pull. Hoping to get those crappy numbers up to something acceptable. IMO with an stock engine and valve train there is llittle value to up rev limiter beyond 5700.

GIZMO

iTrader: (8)

Absolutely, I have had a ton of high rpm race motors with unported LT1 heads. Do a search for Stock Eliminator. I don't spend a bunch of time on the dyno, but my old Camaro made a little over 400 RWHP and ran 10.5's @ 3200+ lbs.

There are several reasons why a ported or aftermarket head is a good idea. One would be more HP at lower rpms. A second would just be be more HP.

Take Care,

Daren

Purple95Z28

iTrader: (6)

Stock Eliminator cars are not the norm. Nobody builds that style of motor/car unless, guess what, you run Stock Elminator.

For street/strip cars, ~6400 is the most you will get out of the stock heads... Untouched that is.