Danny Richie

I have an 06 Vette with LS-2 and A6, and I am looking to do some mods this winter.

New headers and a converter are a given, but I am a bit torn with which way I want to go on the motor.

I know I could add a nice set of ported LS-3 heads and intake with a good cam and new air intake system and lay down 440 to 480 to the rear wheels. And just keep my stock LS-2 bottom end.

Or...

Do I build a new engine with a stroked bottom end making a 408 or 427 cubed motor? And use some ported LS-3 heads plus a little more cam.

This would mean basically an engine swap rather than an in car tare down of mine. And just bolt all my necessities onto the new motor.

This leaves me with my LS-2 (low mileage) complete that I could sell. Maybe I get $2,500 or $3,000 for my stock LS-2?

Will the money that I sell my LS-2 for compensate for the cost of the new short block upgrade?

What do you guys think?

Oh yeah, and I am not putting an iron block motor in my Vette. If I build a new motor it has to be an Aluminum block motor.

Tainted

iTrader: (9)

A bigger motor wont do any good if you dont have the mods to support it.

But a 408 ls2 would be nasty, but id consider staying away from ls3 heads with the 6.0. Your cam and compression is limited with the valve shrouding on the smaller 6.0 bore. A nice set of ported ls6 heads would be a better choice while giving you more compression, more ptv clearance and larger cam selection.

Danny Richie

Well, if I did build a bigger motor then a certainly would get all the mods to support it.

And I know the combustion chamber size can vary depending on how much they have been opened up and polished for either LS6 or LS3 heads. If I just did a head swap on my motor then I would keep my same compression even if I have to have the heads milled a little.

I'd like to know more about how a milled LS3 head might limit my cam choices though. I am guessing I'd have to stay below about a 575 lift? That might be plenty anyway.

And I don't really see how going from a 4" bore (LS2) to a 4.06 (LS3) is really going shroud or un-shroud the values. Aren't those 408's based on a 4" bored LS2 block?

I am looking for the most bang for the buck here, and really appreciate the suggestions.

So upgrade my LS2 or build new motor and sell mine?

Tainted

iTrader: (9)

LS2 bore is 4.000
LS3 bore is 4.060

The cam choice would be limited on the ls2 with ls3 heads because the valve is so close to the cylinder wall already. Lift isnt what determines PTV clearance. Overlap and duration are the 2 big factors for determining PTV clearance.

The LS3 with its larger bore, and more cubes would be the better choice. You open up a larger number of options for cams and can mill heads for some added compression etc and having more power to boot, for about the same price.

That being said, the LS2 is still a great motor, but Id suggest staying with cathedral heads if you stay with the LS2.

Danny Richie

Thanks for the advice.

And if any of the site sponsors here have a solution to offer then I would be glad to hear it.

Tainted

iTrader: (9)

Theres plenty of great sponsors that offer a lot of varients of ls1/2/3/7 engines available as either short or long blocks, and even turn key fully dressed. Just start going down the list but TSP has some great stuff for the price as well as SDPC

Danny Richie

So if I stick with my bottom end then dropping on a set of heads like these: https://ls1tech.com/forums/parts-cla...e-springs.html

... would be a better choice than a set of LS-3 heads?

Then I do a little port matching with my stock LS2 intake and reuse it.

Danny Richie

Hmmm, and it looks like I don't have a high enough post count to respond to his ad.

Oh well, at least I was able to send him a PM.

hotrodT/A

Hmm.... everywhere ive seen says dont bother with the intake. And i wouldnt. I would say maybe your second option with a big cam. Thats just cuz i love big cams

Tainted

iTrader: (9)

Those would be great heads. The ls3 heads are great dont get me wrong, but they are just a great cheap stock casting. A nice set of AFR TFS etc heads will really shine. I reccomend if you get some good heads like those and staying ls2 style then find a used FAST intake.

Danny Richie

And I take it that a set of heads like that will keep my cam shaft options a bit more open? In other words, they would help keep my PTV clearances a little higher (similar to a stock head)?

I'd like to go with a reasonable sized cam without having to have my pistons fly cut.

Tainted

iTrader: (9)

Correct.

Danny Richie

And if the stock LS2 has 64.5 cc heads and 10.9 compression, and I drop these heads on it with 59 cc chambers, how much is that going to effect my compression ratio?

Tainted

iTrader: (9)

That part I cant answer. If you google fomprression calculator you can plug in all your info and it will tell you. I just dont know the formula. It should be a nice bump though.

Danny Richie

Thanks Tainted. You have been very helpful.

I went here: http://www.csgnetwork.com/compcalc.html

I had to fiddle with the dome volume a little to get the correct factory compression of 10.9 to 1. I know the pistons have a little valve relief cut into them. And I had to allow for a -3 cc's for that to hit the factory numbers.

I then dropped the combustion chamber cc's to 59 and it hit 11.697 to 1. I think that might be a little excessive for standard super un-lead. I can get 93 octane around here with some alcohol blend, but I am a bit afraid that might not cut it.

Hmmm....

Maybe that is why these heads have not sold already.

Tainted

iTrader: (9)

Plenty of people run high compression, especially th sstroker folks. you can still safely run that on 93 without any additives. The tuning is the major part for making that a reality and a good cam choice.