Hello all,
I've got a 99 corvette with a bone stock engine at 150k miles. I'm thinking about doing some upgrades and trying to figure out what the best options would be. I've done a cold air intake cause that was cheap and easy. Since I bought the car I was thinking I'd swap an LS3 into it at some point. But I'm having second thoughts about that now cause the prices on a descent LS3 are almost as much as I paid for the car :P Also frankly, I enjoy doing the work on it myself, but I don't know that I can get the engine out of the car with my garage. Looks like it's a pita to get out the top, and I can't lift it high enough to get it out of the bottom. I've got a set of quickjacks that I used to swap the transmission in it, but I don't think that would be high enough to clear the engine coming out the bottom.

So, I'm thinking maybe I'll do a cam, heads, exhaust, tune on the LS1 instead. But, my primary concern there is with the engine being such high mileage, is it worth it? I've done a compression test and I don't think the numbers are great, on the low side of barely acceptable from what I've researched. And the compression between the low and high is definitely not great.
7 - 174
5 - 167
3 - 160
1 - 153

8 - 160
6 - 158
4 - 164
2 - 154

But, if I get into having to do a bottom end rebuild too, then it definitely seems questionable not to just upgrade the entire engine with a better base for future upgrades.

Another point to keep in mind, I'm not looking for any huge upgrades or trying to max out the LS1 or anything. I'd get something fairly mild - mid. I want to keep the car fun to drive on the street and just cruise in. I think targeting close to 400 maybe 450 HP would probably be plenty for what I want. Just want a little more pep in the step when driving it around hehe. This is one reason why I was looking at the LS3, because I know it makes around those numbers stock.

So what do you guys that are more experienced in LS1s / have upgraded them or swapped to an LS3 think?

 

Mines a 98 with about the same miles I did hci on mine and it ran great if it’s a six speed I’d consider putting gears in it too plus you’ll need lt’s too. It’ll be fun for awhile then I added fi

 

I am pushing 100k miles on my 99 this year and I am in the process of adding Dynatech headers.

 

Your numbers are within ±9% of the 160 psi median. Great? Perhaps not. Time to panic? I think I'd be delighted with those results. One question: did you match compression strokes, cylinder to cylinder? i.e. 4 puffs or similar on each?

 

I think if it was me I'd be thinking about a rebuild and adding your mods at the same time. At that mileage I'd just like everything fresh.