92Vette

Hello all, my car is a 1992 Corvette, with the LT1. It's bone stock.

It's my DD so I don't want to do too much to it, but I would like to do some bolt-ons. I am fairly handy but don't have a ton of experience working on cars (I did my own water pump though).

I've researched this subject of 1.7 rr's on a stock engine and it seems like people have done it successfully. However, I cannot find a guide on how to do it.

So far I have come up with what I will need, but I'm not sure what part numbers exactly I should use. If somebody has a proven setup, I'd like to hear what you are using and what problems you ran into.

I need:
1.7rr's NSA (I've heard scorpion is good?)
Guideplates (need recommendations)
7/16 studs (need recommendations)
upgraded valvesprings (good ones! I want to do this right the first time)
hardened pushrods (need help with type and ESPECIALLY length)
locks and retainers
valve spring remover tool

Am I missing anything?

Keep in mind I know all this from reading online only, I do not know anything from experience. I could really use some help, thanks.


*I believe LT1 Corvette valve covers will clear the 1.7rr's with the stock cam, I'm not sure if this goes for the f-bodies*

NewOrleansLT1

Scorpion 1.7rr are good, Trickflow stock length harden pushrods are good, 7/16 studs go with ARP, you need compressed air and the special tool from Autozone to do valve springs.. Maybe someone else can chime in for the other stuff..

F0x Slaughter

I have a valve spring tool you hit it with a hammer and it sucks the keepers out. Its only for heads off the block.

Valve springs depends on the cam.

Ed Wright

iTrader: (1)

I would not waste my money. Tested that on my '96 TA. Made three dyno pulls, with the car still sitting on the dyno, put a set of 1.6 rockers on it. Warmed it back up, made three more pulls. Same day, no weather change. Average gain was 3 rwhp. About $100.00 per HP. Could feel nothing driving it, no measurable gain on the track.
Your results may vary. LOL

92Vette

What do I need compressed air for?

Stock cam. Lift would be .510/.510 with 1.7 rockers and stock cam. Would Comp Cams 918 springs be good for this?

Was your car stock? I think the Corvettes might react a bit different because they have a better flowing exhaust from the factory.

RamAir95TA

iTrader: (2)

Compressed air is used to keep the valves up so the valve stem doesn't drop into the valve guide.

You can bet that Ed's application of the 1.7s was not on a car with stock exhaust.

92Vette

Oh I see. How difficult is it to do this whole thing? I want to become more experienced working with Corvettes so this is something I'd like to do.

I sort of figured that lol, I'm curious what this would do on an otherwise stock car.

Ed Wright

iTrader: (1)

Stock with no cats, mandrel bent off road pipe, and a B&B cat-back exhaust.

F0x Slaughter

I think you are far better off just getting a hold of Advanced Induction or Lloyd Elliot and have them pick you out a valvetrain.

You don't have to go wild if you DD the car.
Going to be a lot better than just swapping in rockers.

CC918 would be fine for this application but as I said you'd be much happier just getting a hold of LE/AI.

CamaroRacing12

iTrader: (5)

Its been debated but others got good results. I personally still run stock everything.

bufmatmuslepants

iTrader: (3)

Tim's valve spring removal too does not require removing the heads and is $35 shipped to your door. You don't need compressed air, just a 14mm socket on one of the crank pulley bolts to rotate the engine over 90 degrees at a time, allowing you to do 4 valves at a time on the ones at tdc.

Personally I would avoid 918s and pac1218s on a dd, too many failures before 20,000 miles to leave me confident. Get a good dual spring, expect to pay around $250 if new.

The cheapest way to do all this if you never plan to cam it is to get a set of self aligning 1.6 rockers and lt4 springs, which are $37 new from jegs. You won't be leaving much on the table, the real advantage is from the reduced friction of a full roller rocker.

92Vette

Will the self-aligning rockers and LT4 springs do okay at higher rpms? I've only heard bad things about LT4 springs, but if the LT4 engine has 1.6 rockers and the same springs then one would think they would be okay...

Say I wanted to leave a bit on the table... should I get those dual springs instead?

I think I'm going to call up Lloyd Elliot today, that should be quite helpful

ScreaminRedZ

iTrader: (3)

Good to see you're getting ready to mod up! Are you going to throw it on a dyno first to get a baseline?

92Vette

Yup! In exactly one month I'll be one the dyno getting my baseline. It's going to be a mustang dyno so I'm only expecting around 250rwhp stock, maybe even less...

Catmaigne

iTrader: (6)

I wouldn't go much higher than 6300 RPM on SA rockers so you're fine on a stock cam. The LT1 has heavier valves than the LT4 but you're not going to be spinning that high so I wouldn't worry about it.

Personally, I think you should stay away from the valvetrain until you do all of the bolt on mods. Upgrading to LT4 springs on a stock cam is grasping at straws because you won't be able to reuse them if you ever cam your car (which is inevitable, horsepower is like cowbell and you always need more). The LT4 springs will float with even the baby Hotcam so go with a nice pair of duals so your motor is future proof.

The Crane 10308-1's are probably the best bang for your buck (they're what I run on my CC503 daily driver). They're stout enough for old lazy XE lobes (CC503, CC306) but still have enough spring pressure to handle more aggressive XFI cams with higher lift you shim the spring height to 1.750" according to Lloyd. They're a more budget minded alternative to the Patriot Gold's everyone is using.

http://www.jegs.com/i/Crane-Cams/271/10308-1/10002/-1
There's a set on Amazon for $15 less but Jegs has a kickass warranty.

Anyway, do the necessary intake and exhaust mods before jumping to valvetrain. It's a can of worms.

CamaroRacing12

iTrader: (5)

slowhawks dyno? where in mass are you?

bufmatmuslepants

iTrader: (3)

Like was said, 6300 is the limit of lt4 springs, and self aligning rockers. If you stay stock cam, you are fine. Lt1 xjs gained 10rwhp going from 1.6 to 1.7 rockers. You need long tube headers and an intake to finish the package, and with rockers, full intake and exhaust and a tune, expect 315 rwhp.

Another thing to add, simply upgrading valvesprings can drop your 1/4 mile time because you will see less valve float, you should be shifting at 62-6300 rpm on a stock cam, and stock springs don't like much over 5200.

Ed Wright

iTrader: (1)

Wow! I have never seen gains like that!
I have tested that a lot. So, this was tested back-to-back, same day while sitting on the dyno?
You can back one off a chassis dyno rollers, drive it around the block, drive back in and tie it down again, and gain or loose a few. Alignment on the rollers makes a difference. May look the same, but still vary. Different days will often test differently also. The weather correction software is not dead nuts either. Normally an untouched vehicle would make better SAE corrected numbers in the summer than winter, even though the un-corrected number were better on a cold day.
That is an impressive gain. I have not seen that on an engine dyno.

bufmatmuslepants

iTrader: (3)

Hopefully he will chime in.

92Vette

I've been looking at some dyno graphs and LT4 springs seem like they still are susceptible to float above 500rpm. I'd definitely go with the dual springs, or possibly beehives, thanks for the advice.

I'd probably get headers as well if I did this.

Peabody. I've heard of Slowhawk, but aren't they LS specialists?



I've been checking out the Hotcam kit too.... seems like a pretty good bang-for-the-buck for a daily driver. No chance I could install it myself though.