Carnage. (was "What can I swap in?")

[ryeguy2006a]

The 243/799 heads actually have the same port designs, just the combustion chamber is larger on the 317 heads. Really depends on what you want to do. A cammed LQ9 with LS6 intake will make some good numbers even with the 317 heads. I think that the head swap to 243 wouldn't be worth more than 20-25 hp. If he went to the LS3 heads maybe would be worth 35-40 more. Personally if you just wanted to get the car up and running, I'd just lap the valves yourself swap the springs and put it all back together with MLS gaskets and the new cam. Otherwise the LS3 top end kit will delay things quite a bit waiting for parts.

[slazisme]

I vote for a 6.0L iron block (I didn't want to worry about sleeving) with LS3 heads and intake, that's what I built and have no regrets, 507hp & 475 ft/lbs torque. You can get LSA heads new for around 665.00 from all the usual places, depending on your cam selection springs might need to be changed.
I bought a junkyard engine stripped off and sold off what I didn't need including the 317 heads and went from there. I did upgrade rockers, 4032 pistons, rods with ARP bolts, pan etc..
Here's an article to ponder:
https://www.motortrend.com/how-to/hr...gine-cam-test/

https://dallas.craigslist.org/dal/pt...513553958.html

[streetk14]

Anyone else wondering why it was idling so high before it blew? Doesn’t seem like the rod bolts not being torqued would cause that.

[NorCal-SS]

Yep (see post3). I understand a data log at this point is likely not available. But if it were me, I’d have the tune looked over by a knowledgable eye before running it again, just in case. Symptoms seem like an extremely lean condition. OP also mentioned possible nitrous usage prior to owning the engine, so who knows what is flashed on the ECU

[derekf]

My assumption is a severe vacuum leak - so my parts purchases included new injector seals and intake gaskets. The engine did literally sit for a decade and a half between assembly and first fire so I suppose I should count myself lucky that I didn't have other leaks. At least as far as "lucky" goes at this point.

The tune was literally the stock GM tune - not that I could tell you where I found the "2000 Chevrolet Camaro Coupe Manual LS1 5.7 Litre (PCM 09381344).tun" file; using EFILive to do a diff between what was on the PCM as purchased and this had only any real differences in the VE table - and there only under 1200 rpm - and in the VE-while-cranking table.

[streetk14]

Doesn’t seem likely the tune was to blame if it was a confirmed stock file for an LS1 F-body. The high idle is a head scratcher, and a vacuum leak would make some sense. Seems like it would need to be a massive leak to do that, but I guess anything is possible.

I was thinking it could have been super lean from something like low fuel pressure, but that doesn’t explain the high idle. What about cylinder 5 becoming hydro-locked from a stuck injector? Either way, you’ll definitely want to be careful. It would probably be a smart move to smoke test the intake system before you try to fire up the new engine.

[derekf]

I found photographic evidence of my vacuum leak:



I also found bits of piston in the intake. Glad I took the time to look around it.

New engine is mostly together and will be starting it probably late this week, thanks for all the advice.

[NorCal-SS]

That’s great detective work! That would certainly set my mind at ease moving forward.