questions about ls2 402

[merriman44]

Alright so I'm worse than a fat woman on a crash-diet at the buffet and just keep changing my mind with how I wanna proceed with this project. It started as a stock ls1 build for the 69. Got ls1 and it was blown up sir. So poop, but then I think I can build a ls2 for about the same money since I have most of the extras off the first engine. Now I'm thinking a 402 would be cool but have a few questions. Does the ls2 need clearanced for a 4" crank? Also, I want to get good gas mileage with my combo so should I stay away from a stroker even if I use a smaller cam? I'm thinkin to go with the L76 intake and L92 heads when its all said and done.

All comments welcome so hopefully I can direct this project to her place in the buffet line.

THanks!!

[QSPres]

There are several parts that are different between the two engines.

It does nto need to be clearanced for a 4" crank. More CI, more air and fuel it uses. No way to get around that. Building a stroker that makes power down low will allow yuou to keep the RPM's down, which should get you a bit better mileage.

You won't be able to build a LS2 for the same price as a LS1. Not even close.


But there are stroker LS1's too....

[merriman44]

are you sure? I have the crank and rods already and they are the same. All I need for a BASIC and I mean basic short block is pistons. Then the heads and intake will work for now because a top end is easy to change. All I'd need is to relocate a few sensors (conversion kits), get some new front and rear seals and a few other little stuff and voila! Tell I'm wrong if I am but, if I just ended up building the 364 I think I can get it done way under 1800. Budget minded bargain shopper I am. And if I were to buy a stroker crank that wouldn't be that much more either.

Once again the comments are welcome and I'm definitely learning through error here. So the more online mistakes I make the less real world ones.

[datsbad]

You cant use L92 heads unless you have a 4.00 bore.
You dont even want to change out sleeves to get the bore size you want . The cost wont be worth it .

I think first you need a HP goal , you can do so much with a LS1 as well as a LS2, but you need a plan if you want to spend money wisely.

Dont forget machine shop time, balancing and all the cost adds up quick .

So , what is your plan , rwhp ????

[merriman44]

around 400-450 rwhp. I think I'm just gonna go with the 364. I wanted to build a ls2 so that the peak numbers were at lower rpm. I want a very streetable 400-450. My understanding was the bigger the volume the better (within reason).

[merriman44]

No I don't want to resleeve an engine because it crazy expensive. However I could use the l92's with the 4 inch bore of the ls2. Plus, I just bought a forged set of rods for 200 bucks from a fella on ls1tech. The rods are interchangeable I believe for the ls1 and ls2 (someone correct if I'm wrong). I already have the crank. All I will need is pistons and a balancing. The block will be a brand new ls2 block that I'll be picking up soon for 750 (the shop was overstocked good for me )

[QSPres]

Forged rods for what pin height?

[merriman44]

"Rod specs, 6.125" length, .945 pin, standard aftermarket LS1 build"

[QSPres]

I believe that is a stroker rod..

Make sure you get the corresponsing pistons.

[TurboLark]

No I don't want to resleeve an engine because it crazy expensive. However I could use the l92's with the 4 inch bore of the ls2. Plus, I just bought a forged set of rods for 200 bucks from a fella on ls1tech. The rods are interchangeable I believe for the ls1 and ls2 (someone correct if I'm wrong). I already have the crank. All I will need is pistons and a balancing. The block will be a brand new ls2 block that I'll be picking up soon for 750 (the shop was overstocked good for me )

Make sure to bore that block .030 over. If you dont you will cause a lot of valve shrouding with the L92's.

[merriman44]

You can't bore a aluminum block 30 over or you'll be eating the water jackets right? As far as the rod goes, I'd like to here more advice on that because I think that the rod is a standard length for aftermarket.

[QSPres]

You can't use a L92 head on a LS1 block unless its resleeved... I would personally buy a set of ported 243's... Same flow numbers..

What is a standard length for "aftermarket"? Its either a stock rod length or its for a stroker crank..

I just bought a Eagle stroker crank and rods and I'm pretty sure their 6.125" in length.

[TurboLark]

You can't bore a aluminum block 30 over or you'll be eating the water jackets right? As far as the rod goes, I'd like to here more advice on that because I think that the rod is a standard length for aftermarket.

Oh yea, you have the LS2 block, not the iron one. Well, I think the L92's will work, just not that well. They have a very large port(260cc) for the flow they have, and shrouding them even more makes it worse. Most info out there suggests to have a minimum of a 4.030 bore for them, with 4.060 being better(what the heads were designed for).
I am looking at building a 408 using an iron 6.0 block, and I am still not sure the L92's are the way to go. If you are on a major budget, than they are the nice choice, but a nice set of AFR or TFS heads will produce better numbers. there seems to be alot of issues with camming the L92's, probably because the air velocity is so lazy with the big port.

most people seem to use a 6.125 rod with a .927 pin(standard SBC stuff). the rod you have is fine as long as you get the right piston.

[merriman44]

Thanks for the info. Really appreciate it. Didn't know the l92's had such big ports. Plus was only going to use them if I went with the stroker, which I am now not going to.