So if you look at my post history you’ll see I was originally looking at a c6. The deal with that car fell through and I had some medical issues the decreased my budget and put the project on the back burner.

Earlier this week I purchased a base c5 with 200k miles, and I know what you’re thinking but I got a really good deal on it and I’m actually excited about a restoration build. So far I’ve replaced a loose tensioner, alternator, and battery and the car is running great. It got a new transmission about 30k miles ago which makes my main concern the motor.

I’m trying to decide what route to go with the motor situation and having trouble deciding. In your opinion would it be best to rebuild the motor or go with a used lower mileage LS. I’ve never rebuilt a motor so I feel like it would be a cool learning experience and that way all the money is going towards beefing up the engine for more power down the road. On the other side of that I feel like I could trust the motor more if it had less miles on it but then I’ll have to spend additional money to build up the engine to handle power.

If I decide to build the motor what do you think I need to replace. Full Valve train, rods, bearings cam, and what else? As far as a replacement motor, should I go back in with an LS1 or go for something with a bit more displacement?

If you didn’t read my previous posts I’m planning on building a 10 sec car that I can street drive if I want to. I’ve been wanting to hit around the 600-700 mark with an A&A kit and meth injection. This is just a passion project to do with my father while I’m younger and able and not worried about kids. Looking for any and all advice.

 

Whats wrong with the motor currently?

 

Nothing wrong right this second with it, I do get a smell when I get in it hard. Maybe an oil smell, it not a strong one like I’ve smelt in the past with other bad engines. No smoke coming from anywhere, nothing coming out of the exhaust so it’s okay for now. Just worried about longevity because I do plan on driving it a good bit and starting power mods at some point.

 

If it ain't broke, don't fix it. Pretty much any C5 is capable of high 12 second 1/4 mile times at 110+mph with a good tune, and good tires......

 

yes, some oil will get burnt through the pcv at high rpm. If theres nothing wrong with it I wouldn’t go tearing it apart. You might be able to reach your goals with the stock ls1 + boost, Id do some reading here and on ls1tech. Me personally, Id run the motor you have with moderate boost. If you decide thats not enough then build or buy whatever forged motor your budget allows.

 

Also Im sure you know the stock trans+diff will be on borrowed time when you start launching it at 500+ whp

 

I have a 170,000 mile '99 with a NA 427 motor. About 450+ hp and tq at the rear with a street tune for touring the open road. Rear and tranny never opened. Great ride.
Enjoy rhe ride George.

 

If it ain't broke don't fix it ...until it is broke. Then go nuts! Go for the power mods on the rebuild. If you plan to go FI and 600-700 at the wheels is your goal this can easily be done on a LS1. No need to go bigger on the cubes to get to that power range.

Seeing that your goals are to run 10's. Then you'll need a lot more power at the wheels to get you there. Which you are aware of. The procharger, heads, a bigger cam, new valve springs etc.. Heck while you're at it go with forged internals.

Just remember...easy doesn't equate to cheap. It cost me about $20k in parts to get to 640rwhp on 93 pump @ 10psi on a completely fresh LS1 rebuild with forged internals. If you are starting with a bare block I would spend the extra $ and forge it. This way your investment to get you to 10 seconds isn't a ticking time bomb.

You could always upgrade the valve train and procharge it now. Then build it if and when you blow it up. You may not see 10's but you should see low 11's all day with the right tires.

I was running mid 11's with a 232/236/113 custom cam motion cam, stage 3 #241 WCCH heads, and 4.10 gears in a naturally aspirated MN6. And my driving leaves a lot to be desired.

You have a lot of options. Just depends how committed you are, how much time you want it laid up, and how much money you want to spend.

Either way just enjoy the journey with your dad!

 

There is a 770K mile C5 at the NCM that has not been rebuilt as the story goes. I have over 200K on my 02 and a friend has over 266k on his 2000. We both have had our respective cars for around 18 years. About 2 yrs ago we did the oil pan gasket replacement on both to stop the oil leaks. Both have had front and rear main seals replaced also.
I would not hesitate to take either on a cross country drive at any time. Just make sure the oil is good and tires are aired up.

Gary

 

Find a used LS1 engine, buy it.
Learn how to rebuild engine with it.
That'll take some time.
Swop engines.
Sell old engine.
Congratulate one self.

 

There is an easy way to put your mind at rest. Do a compression test on all cylinders. Check you numbers 1-8 and report back.