Hello

This winter im going to take the engine out for some overlook.
The car is a 1991 corvette 6spd with the hotcam kit installed, LPE ported 113 heads, headers, stock TPI.

First im going to change the intake. Im thinking lt1 conversion here? *** bad?

While I have the engine out of the car what should I change?


all bearings? Should I chagne the cam bearings aswell? What to get here?

Pistons to stronger ones ( i would like to be abel to run nitrous later )? What is your tips here, what parts to get and what compression should I run?

How strong is the crank and rods in the l98? Can they handel the increase in RPM ( due to the lt1 intake i should see 6000rpm often )?? Or must I change them also?

Should I internal balance the engine while I have it out?

Should I chage to a more "angry" cam ( like the cc306)? Or is my ported LPE heads the bottleneck here after i install the lt1 intake? Is it better to get better heads?

Thanks for your time..

 

Stock L98 bottom end. Never pulled. Never rebuilt.

Tim

 

thats nice But when I have the engine out of the car shouldent I change the bearings at least? And all the bolts to ARP

 

Sure.

Tim

 

so what you saying is that its ok to swap to the lt1 and take the engine to 6200rpm at wot sometimes? Thats good news for me.

Is it worth something to make the engine internal balanced?

 

It wouldn't hurt to balance and blue print the engine. If you want to run a shot of nitrous then forged internals would be a good idea. Theres one thing to remember when you build up your engine. Yes some engine's are running nice HP and TOQ numbers. But not every engine is the same. Maybe the one you have was made when Bob the alcoholic GM engine builder was working and didn't tighten a bolt the right way. Also what are you going to be doing with your car? Street? Strip? Autocorss? Or a combination of all. You want to run nitrous right? How much of a shot you want to run? Are you willing to run race gas? If no. Then run a conservative compression ratio. Like maybe 9:1 or 9.5:1.
Decide these things first. Also if your running nitrous you might want to consider a nitrous cam. I think comp or crane sells them. They're sapposed to be pretty good even when your not running the juice all the time. Give some of the cam companies a call and see what they would recommend.
As for intakes. I personally like the mini ram. I plan on getting one soon. Does your state have emission requirments? If so you might want to get the hsr,sr, or LT1 intake. The sky's the limit here.
But all and all a little refreshing up couldn't hurt the old engine.
Sorry for the long post. I hope I've help you out and not caused even more problem dude.

 

If you are going to pull the whole motor out, you might as well rebuild it.

I would bore block .030, get forged flat-top pistons with 2 or 4 valve reliefs, turn the crank, new bearings and ARP bolts, resize and weight match the rods, slide that Comp 306 cam in there if you are going with the LT-1 intake, and get a halfway decent set of aluminum heads if it's in the budget, have rotating assembly balanced and have the shop reassemble it.

Dont use that cam with the stock heads though.

 

thanks

I already have the hot cam and i think I can make good power with that, with a pair of good heads. Im thinking afr 195 or trick flow?
Whe only have sniffer test, so egr isent a demand.
I whant a low 12 sec car ( under 12.5 ) that is streetable. And high 11 with NOS.
100hp nos is my goal. Im only running 98 octane gas ( ron ).
I have looked at the lt1 intake for some time now, and I think that would be my choise, I think that could work great with my 6spd.
Im only a bit worried about to take the engine to 6200rpm during wot

What do "they" do when you "turn" the crank?
I understand about weight match the rods, but resize, please explain?

The heads i have now is the alu 113 vette d-ports, that are LPE ported. Are they "good enough" for my goal?

Will the cc306 cam make alot more HP then my hot cam?

If do what you say about "resize" balance etc etc. Will the rods and crank handel 6300rpm?

And if I lower compression, will that hurt my preformance and throttel response much?

thanks

 

98 octane should do. Go to NOS's site. They have a chart that you pick and choose your compression and nitrous shot with. I wouldn't get 195's. They are ment for a different style manifold. Stick with 190's. For 12's you might be looking at going from a 350 to 355 or even 383 like 1badz said.
This might sound wierd but if you have your heart set on an lt1 intake. Why don't you just save yourself sometime and hassle and just get a whole lt1. Build it up how you want it. That way you'll still have your 'vette to drive around and you'll just be waiting on the motor.
Tired....sleep.....uhh

 

will do.

so the stock crank and rods should be fine?

 

Truth is - who knows. You need to ask yourself the question as to whether you want to play poker or not. I'm a gambling man and have already accepted the results of what WILL happen. It's only a matter of time.

FWIW - I would at the very least replace the rods with some GM PM forged rods using ARP waveloc bolts. I've seen these L98 cranks go 11's. Just depends on it's condition. Keep one thing in mind - Nitrous is violent on the engine. You are going to stress the parts more than an NA setup.

Tim

 

ok, i see...

where can i find those rods?

But if I balance it all the internals would handel more rpm safer?

 

Buy some books or check some out from the library. You should know a lot more than you do in order to achieve your ultimate goals.

Tim

 

Hey devilfish I think I might have what your looking for. Forged SRP flatop pistons, forged Eagle crank and rods.
I even have an 87 block already bored .030 and prepped for assembly. Its all ready to go just needs put together.
Drop me a pm if your interested.
Later Barrett

 

I have the stock crank and rods and rod bolts (all reconditioned), with Speed-Pro forged pistons and the motor has performed great. I shift at 6000 rpm, I don't think I'd trust the stock bottom end to spin much higher on a regular basis though. But if I would have had the money at the time, I would have gotten an all forged 383 assembly, no doubt. The higher you spin the motor, the more built it will need to be to survive. So the CC306 I personally wouldn't use w/ a stock bottom end if I wanted the shortblock to last long.

 

I also wouldn't bother spending the money on AFR's if you have a set of LPE worked 113's. Especially if that work was done by a CNC machine. They work pretty well

 

yes I have books and info. And this topic is also for me to learn more. You must start somewhere right...

So you say that my hotcam makes power more early in the rpm range then the cc306? But not as much,,