Update: 412 rwhp!!

I have a well loved vette. I've owned it from 40,000 miles. It's now got 190,000 miles on the clock and has been the most reliable car I've ever owned.

From reading all these posts for the last decade, the most common cause of stock engine failure (not stupid operator error) was valve spring failure. So, being so high in miles, I thought maybe I'd take a pre-emptive effort and change out the heads. I happen to come across some barely used 241 heads for a song.

Then my buddy says "you should really add a cam while you've got it apart..."

The fiscal death spiral begins.

So, I gave up on the 241 heads and picked up a set of LS2 take off 243s (used). Went with a 222/226 115LSA baby cam (emissions legal). Picked up an LS6 intake (used). Lost my mind and bought SLP long tubes, high flow cats & X pipe (used). MLS head gaskets, LS7 lifters, gaskets in general, head bolts, pulley bolt, PAC 1218 valve springs.

Existing mods are Blackwing intake and Corsa cat back.

TPS locally - had a deal with their dyno pulls. Do a baseline (none of the mods except for existing):


I was kind of surprised at the results of this aging engine. (LS1 intake, 853 heads, many many miles)

What are the bets of the updated HP levels? (Assuming the clutch survives.)

I'm hoping 400-420 with a big fat torque curve.

 

Not sure on the final numbers but those are really good base numbers.

 

Id guess 390whp, if a 6speed car.

Jay

 

I would guess about 405

 

 

I'm guessing 405-410rwhp

 

Being a 2000 block with 190,000 miles on the clock. Hmmmm

 

you're not going to freshen the entire thing?

um what?

 

275 RWHP LMAO

Realistically,,,, 410RWHP 390 Tq Bet is ON!

 

405hp/380tq

 

THIS,,,,,,,,,,,,,,,,,,, Should be FUN!!!

 

Mitch I had some thing close to what you have here is a copy of a post I had a stock LS1 WITH A CAM AND HEADERS and 853 heads and a Vararam cai and it made 383.6 RWHP / 360.43 RWTQ


Then had Charlie Wilson at RPM Motorsports build this


LS6 FORGED SHORT BLOCK

RE-BUILT 243 HEADS 5 AXIS CNC PORTED

FAST 92MM MATCHED PORTED TO HEADS

PORTED LS2 T.B.

CYLINDER HEAD WORKSHEET


Type/ casting LS6 -243
Spring Kit Patriot GoldX
Valves SS
Valve Job Serdi - constant flow intake & exhaust
Combustion Chamber 62 cc
Intake Flow 288 CFM
Exhaust Flow 240 CFM
Flow with Intake attached 0.787
(RPM Ported Fast 92 mm)


Cam Specs

ZZ-*‐005-*‐X LSA 114 +2


Intake Exhaust

Duration 224 230

LIFT .589 .595

not too bad for something that will pass emissions with flying colors

My new numbers are 440 rwhp and 423 rwtq

all work was performed at TPS Motorsports in Campbell Ca.

Pops

 

Freshen up the whole thing.... That's a valid question.

So far - I've never read a thing about the lower end going out without some wild modifications. For those of you with garage queens, this is essentially a very similar engine that is in all the trucks, suv's, etc. They last for a really long time.

Nothing on the lower end will make extra HP - unless you bore or stroke it. So it works great - don't fix what aint broke.

I have a friend that is now in the mid 650 HP rating with the stock bottom end. (blower) He's ready to drop in a forged lower end, but he's going to wait for the original to go before he drops in the forged engine.

So - I may be wrong - but I'm hoping that the bottom end just keeps chugging along like it has been for so long.

Hope it doesn't bite me.

 

I'll just throw my 2 cents in because I have nothing better to do, but while the engine is "essentially" the same that is in the trucks and anything else GM put a SBC in, very few, if any of those engines were in an application where they could be spun north of 5500 rpm nor subject to the same "normal" use they see in a vette.

While you likely won't have any issues if the engine doesn't exhibit any signs of wear or concern, there still has to be some economic benefit in terms of cost savings if you were to freshen the bottom end as well. At the same time you could probably punch it out for some added displacement and not have the worry of "is that a knock I hear" coming from your recently "upgraded" engine.

If I was going to be diving in as far as you are, I would be doing the whole thing, bumping the compression a bit and aiming for 450rwhp as a minimum.

Then while the engine is out I'd be replacing the entire clutch/flywheel/TOB/slave/MC.

R.I.P. Money.

 

Mitch have Mike do a compression check on the bottom end and I would at least put in a new oil pump while you have it down your choice but better to be safe then sorry


Pops

 

I put my 224/230 .602" cam and AFR 205 heads on my LS1 back when it had 155k miles on the odometer. Now it has 240k miles and still running the original shortblock. Go ahead and add a new oil pump and timing chain, bolt on your new heads, cam, intake, headers and have fun for a long time.

An LS1 with 853 heads, small(ish) cam and headers will typically make 380-390 rwhp. With your 243 heads, cam, headers, LS6 intake - a manual transmission car should put down 410 to 420 rwhp. It will be a huge power improvement and you will wonder why you didn't do it 100k miles ago. Be sure to report back to this thread when you get the dyno numbers.

 

I'll take a look at the oil pump. There's an LS2 chain and LS7 lifters in the mix as well.

 

Some pics of the teardown
Before:


Hood marked


Hood off


Intake off:


Cooling system off:


Steering rack out:



Balancer bolt off:

 

I'll be about a week behind you, including the Y2K MY car. Mine has only 80K miles. Still, I'm tempted to do the lower end.....mine has that anoying piston slap that never totally goes away. And a 383 sounds nice.

Looks like a great opportunity for a lot of cleaning!
Have fun!

Interesting that there aren't bolt holes for use with a normal balancer puller. I guess I'll have to research what type of puller is needed. The thing looks rather weak in the center hub area.

Ron

 

I'm looking at doing a cam swap very soon, so this will be nice to follow.