Myron37

Hey guys,

Looks like I'm gonna be doing a motor swap soon. My current config puts 411/389 to the ground.. its an LS1 with 243 ported heads, trunion upgrade, TSP cam, long tubes, FAST 102 set, MSD coils, SLP85 MAF...

question is, how well will these heads flow on an LS2 408 inch motor? would i be doing myself a great dis-service by using them? Was just going to get a short block and use my existing cam as well...

Myron

HCI2000SS

iTrader: (2)

No it will work fine and everything, but the larger cubes can handle a better head more efficiently and make more power while still retaining good drivability. Basically you won't see much more hp (little broader torque curve though) by going with the 408 if all else is exactly the same

Tuskyz28

What cam you currently have ?

The 243 heads can be really improved from a nice port/cnc job.....

On a LS2 block you'll be at a 402ci... not 408ci.

flintwrench69

iTrader: (11)

Its probably a bored over ls2 so 408 is possible.

Myron37

the heads ARE ported... the cam is a TSP part # 228-112... the block is bored 30 so it is a 408 inch motor... Just wondering if I should go with a different casting on the heads and a different cam....

Current LS1, 346 inch with these components puts down 411/389.... Wonder what I would gain with the addition of 62 inches?....

Myron

SoFla01SSLookinstok

I'd say your heads may be fine. Get them all checked out. I would definitely get a new cam for the new motor though.

Tuskyz28

I doubt it.....
Most people either go 0.005 or 0.010 over at the most...

408 Ci is 0.030 over using a LQ iron block. LS2 block is aluminum.

In the real world I rather have a 402ci LS2 over a 408ci motor LQ block. I'll take 6 cubes less anyday smiling knowing I don't have a 100 pounds more of weight on the nose of my car. Especially all motor setup.... boost wise I'll go ahead and bite the 408ci bullet.

flintwrench69

iTrader: (11)

Must be possible, I've seen 408 ls2s for sale. Not saying its better than stock bore but they're out there
http://m.ebay.com/itm/191553685702?nav=SEARCH

Tuskyz28

Good price!! Truth is it will not be a big horsepower difference between a 402 and a 408..... maybe 10 more at the crank. Rule of thumb# most LS motors make 1.5 horse per cube is possible.

Myron37

the one I am looking at is aluminum LS2 bored 30 over.. he said If I wanted to boost it, he would go with something else... It has all Lunati internals #24 Reluctor and its about the same price as the one listed in the ebay add above...

I'm just sick of trying to get the my current motor to act right. It burns more oil that I am comfortable with event though GM says its within specs... Damn thing has an intermittent miss that I cant figure out.. To solve the oil issue, I put in the proper PCV and a catch can.. I have crank case vacuum at a perfect 4 inches per mfg specs. I just put in new plugs and wires and valve seals as well... Figure I will throw in a new shortblock with my existing heads and intake, upgrade the injectors and coils and there isnt much left to cause it to freak out like it does...

this car has all the upgrades and only 76K miles.. I have a 3100 dollar 12 bolt 33 spline axle under it that has less than 1000 miles. I couldn't get dick for it burning oil and missing like hell... Figure if I put a new motor in it, I may not loose as much money when I find a buyer...

Myron

redtan

iTrader: (5)

ERL does alot of those and have never heard of any issues with them.

While yes it's kind of silly for an extra 5-6 cubes, doesn't mean it's not doable on a specific build.

Last C5

My LS2 408 stroker is also an aluminum engine with all forged internals. I used the AFR 230 heads and probably a little more cam than you want for a street car, but it's putting down 530 to the wheels.

Myron37

@ LastC5,

How do you think your heads perform compared to ported 243's?? Mine have the trunion upgrade and comp double springs and Ti keepers..

Also, What cam and exhaust system do you have? I like the lope of a big cam, and this is just a toy for me so not too worried about driveability..

I have pace setter 1 7/8 long tubes and 3" ORY with a magnaflow muffler, your putting down great #'s, hoping my exhaust doesnt choke it...

Tuskyz28

No ported 243 head is go match the performance of a afr 230 head.... that's a mean cylinder head bro.

Last C5

I've never had ported 243s but the published flow rates of the 230 are better. The heads were the 72CC heads that I had milled to 67CC to get my compression to 11.5 to 1. My cam is a Brian Tooley 235/242 .621/.595 on 111 -3. The engine runs Jessel rockers, Morel lifters, and Ferrea duals. I run Dynamax 1 3/4 inch headers to keep the torque up. Mine would have decent driveabllity if I hadn't installed an extremely light flywheel, clutch, and pressure plate for the track.

05LS2C6

Anybody have FLow #'s for ported 243 heads?

I was "told" that the LS3 had oil return draining issues, I do not know if this is fact or fiction, so I would rather do what you are doing and port the 243 than sell the 243 and buy the LS3 heads and have issues, plus the intake would need to be swapped out too to use LS3 heads

Myron37

Unfortunately all LS motors have some oil issues.. I have a doc from GM stating the oil consumption problems... They say that manual transmission cars driven hard (over 3K) and the use engine braking can result in oil consumption of 1qt per 500 miles... IT also says allow 15 minutes for oil to completely drain back into the crank case before checking...

I completely re-did my PCV system and added a catch can but it still burns more oil than I'm comfortable with, but according to this GM doc, I'm within spec....

Myron

05LS2C6

Good info Myron! I have a catch can but on a stock engine and casual f=driving, I have not had much oil in my catch can so far.

Myron37

your prolly fine then... but for me, It burns enough oil that I would basically never have to change it being I have to add 4 quarts in 2000 miles!

M.BOZZ

iTrader: (14)

Dam, thats alot of oil. I would recheck the letter head to make sure its not for a northstar motor, lol