Future LS Build Advice Needed

[DreamRyder1963]

I have decided that I am going to build a LS engine for my V8 Corvair build. The car will be sitting on a G-Body chassis; it will most likely be from a '84ish Monte Carlo SS. My goal is to make 400-500 hp naturally aspirated without spending more than $3500-$4000 on the engine. I have not decided which LS I will be using, but it is likely going to be a 5.3l due to the cost and aviability. I have heard that it would only take a good cam swap to make these numbers but I would like to known for sure. Any help or advice would be appricated.

[67rally]

I have decided that I am going to build a LS engine for my V8 Corvair build. The car will be sitting on a G-Body chassis; it will most likely be from a '84ish Monte Carlo SS. My goal is to make 400-500 hp naturally aspirated without spending more than $3500-$4000 on the engine. I have not decided which LS I will be using, but it is likely going to be a 5.3l due to the cost and aviability. I have heard that it would only take a good cam swap to make these numbers but I would like to known for sure. Any help or advice would be appricated.

400-500 flywheel or rear wheel hp?

[srh3trinity]

You should be able to get into the low 400's with a heads/cam on a 5.3, but there is a pretty big difference between 400 and 500 hp. If you are wanting to be at the upper end of that range naturally aspirated, you would do better starting with a 6.0 block. Soend some time looking through ls1tech.com for 5.3 builds.

[DreamRyder1963]

Crank hp would be fine but obviously whp would be preferred. My original plan was 300 whp with a sbc but I have decided to go the ls route instead. I figured with ls 400 should not be hard.

[andrewb70]

Crank hp would be fine but obviously whp would be preferred. My original plan was 300 whp with a sbc but I have decided to go the ls route instead. I figured with ls 400 should not be hard.

You may want to reconsider your goals...unless you are willing to live with a wild cam. I have a 6.2L (basically an LS3) and the combo makes 420rwhp...Granted, I am using a very mild LS7 cam, but an almost 1 liter of displacement makes a huge difference. I'd say that if you build a moderate level 5.3L that 350rwhp is a more realistic goal. If you want to spend extra on posted heads and a wild cam, then 400rwhp is attainable, but again, you have to be willing to live with the combo (and the extra cost of good heads).

Andrew

[DreamRyder1963]

I would frankly be happy with 350 whp. The car should only weigh around 3000 lbs. I have about 300 crank horse power in my 3800lb '71 C10 and its no slouch. I found a thread on LS1tech.com where a member was making 351 whp with a cam swap, headers, and a LS6 intake. I was already planning on swapping to a LS1 intake simply because it looks better plus the performance gains.

[garys 68]

First off, the majority of hp increase with cam, etc will be in the 4000rpm range (the dyno graph below is from LS1tech on a 5.3 cam swap).
If you want near 400 hp, just get a 6.0. With an LQ9 you're nearly at 400hp stock.
Just curious, are you keeping the corvair rear engine layout? If so the corvair trans would be better suited to an unmodified 5.3.
https://static1.pt-content.com/images/pt/2014/08/th_dyno_zps61c4cd65-1.jpg (http://s18.photobucket.com/user/rdoact/media/dyno_zps61c4cd65.jpg.html)

[DreamRyder1963]

No it will have a front engine rear drive. The engine will depend on what I found in my price range when I get around to finding an engine. Obviously I would prefer the large engine if possible.

[Bonehead]

Throw a cam in it, a small turbo with 6-8lbs of boost and call it done.

[SD67]

My advice (passed on from a trusted engine builder) is go bigger than you think you will need now, because you will want it later, probably in the middle of your build. You have already changed your mind and increased your requirements once, spend a bit more and get the 6.0.

[DreamRyder1963]

That's good advice and I've started looking around at the larger LS motors. One question I did have is there much difference power wise between the gen 3 (ls1 ls6) and the gen 4 (ls2 ls3) motors. Is it worth the difference in cost?

[csouth]

I would just get the L92 then change the intake and cam. You can't beat starting with a 6.2 L92 over a 5.7 because an LS6 will cost as much as an L92.

[WallaceMFG]

In a car as light as a Corvair, even a stock 5.3 is going to make that car into a rocket compared to the flat 6 it has now. If it were mine, I'd just get whatever was in my budget to get, because its going to be fast no matter which LS motor you put into it. And there is such thing as too much power sometimes lol

[DreamRyder1963]

Thankfully, I am in no hurry to finish the project so I have plenty of time to find the right motor and build it properly.

[davidomilligan]

you can go with an lq4 and get one with a trans for pretty cheap swap your cam and maybe heads if you want. and you will get what you are looking for and ive heard the iron blocks are better to boost also

[DreamRyder1963]

After looking at local builds and doing some quick math on weight, I have pretty much decided on a 5.3l with headers and a LS1 intake coupled to a tremec t56 from American Powertrain. This is unless I trip over a killer deal on a different displacement. This combo should increase the current power to weight by a little over300%. It should make for a quick car while still make it comfortable todrive on long trips.