Do I rebuild my SBC or swap for an LS3?

[Ricko1966]

It can happen. On my old 400 I bought it and found out later some lobes on the cam were wiped out. Replaced the cam. Then my dad upgraded the heads on his 290hp 350 crate. They only had a few thousand miles on them so I put them on the 400. Instantly started using a ton of oil. It never leaked, couldn't see it burn, but would use a quart every few hundred miles.
So gave that engine away and bought a crate 383... and then had all new headaches and a money pit.

Okay now let's do some math on this.Engine didn't burn oil,changed heads it's an oil burner. Now your old heads .intake valve opens,intake /intake valve closes,compression,/plug lights it off,power,/exhaust valve opens,exhaust. Now your old heads and your new heads performed the exact same function. New heads aren't going to affect vacuum unless your old valves weren't sealing. The only way I could see new heads making you burn oil is a problem with the new heads,an intake gasket,or a head gasket. I'd love for someone to explain this to me cause I've put probably 100s of fresh heads on used engines without having this happen to me. I'd be open to learning what I am missing in this equation.

 

[DoubleDingo]

When I was getting the head redone for my 292, both Pop and the machinist told me I am a fool if I don't redo the lower end or do a full rebuild, because the top end having better seal would pull oil past the rings. I figure it happens on the down stroke until a valve opens to relieve the seal. With round cylinder bores and fresh rings properly seated, the oil can't get by.

Edit: If it's an old engine and one doesn't want to do a full rebuild, one could hone the cylinders and re-ring the pistons, but that won't help much if the bores are out of round. I did mention out of round when I gave the heads-up about that to the OP.

 

[Ricko1966]

I've done it both ways. My own junk if the heads are off they usually get rebuilt and new rings and rod bearings. Just because it's easy to do rings and rod bearings then. But when customer cars would come in with a blown head gasket or burnt valve etc. We just valve jobbed and surfaced the heads, and right back on they went. We did that at least once a week and I worked there over a decade. Anyways maybe we got lucky all the time or maybe the you shouldn't put fresh heads on a used block is a wives tale. IDK

 

[Rusty Nail]

Lol has anyone seen the OP lately?
I think we ran him off pages ago...boy this is fun.
They oughta open the politics thread back up.

 

[DoubleDingo]

I've done it both ways. My own junk if the heads are off they usually get rebuilt and new rings and rod bearings. Just because it's easy to do rings and rod bearings then. But when customer cars would come in with a blown head gasket or burnt valve etc. We just valve jobbed and surfaced the heads, and right back on they went. We did that at least once a week and I worked there over a decade. Anyways maybe we got lucky all the time or maybe the you shouldn't put fresh heads on a used block is a wives tale. IDK

On my 292 I was just going to hone the bores and replace bearings and rings, but then figured a full rebuild would be better so everything is trued-up. It'll be nice to break-in a new engine, haven't had that opportunity for a number of years.

 

[Ricko1966]

624 heads, super low milage,Plainfield Illinois . Not great heads but a bargain for somebody building a daily driver.Ebay auction and this the price for the pair. I hope helps somebody.

You must be registered for see images attach

 

[Rusty Nail]

I replaced a cracked set of 624s one time.
On this msb even! Everybody watched me put #416 (305) heads on a 350.
Ran really great - burning 91 octane.

It dont matter, the OP split long time ago. I thought the World SR heads was a pretty good idea and then what? Effing crickets.

 

[Rusty Nail]

416s are fantastic. I had the piss worked out of em..only then would that truck burn the 33s!

 

[Ricko1966]

Oh I wasn't pointing those out to be a performance head at all. I wouldn't spend a dime or ten minutes working them. I just figured somebody on here has a beater that needs heads to get him to and from work. You can't valve job any head for what he's asking for a pair ready to go.

 

[Rusty Nail]

They are very common and yeah, $250 is the entry level price.

I have a perfectly good set of early (1975) 882s -with steam holes- sitting here, not doing anything. They're orange.
Took em off the 408 to swap for built,big valve, World SRs i bought from @Honkyjr.

 

[cjdock]

@cjdock
You know people drove 350 chevys all the time,cross country,to work everywhere when they weren't worn out right? Do think someone who bought a 1999 Escalade with a 5.7 didn't think he could drive it 1000 miles anyday he wanted?A properly built 350 tuned correctly is rock solid reliable.Milage compare a 1999 suburban 5.7 to a 2001 suburban,5.3 pretty similar the milage difference from 1980 something to 2001 comes from engine management.

I'm a fan of the 350 for sure. I'm 61 years old and have had plenty of them. But now it's the new "350" ls swap time! I just picked up an 03 silverado and pulled the motor/trans/harness/pcm and a lot more. I'll do a gentle refresh on the motor and then start the install. Its a big deal to do but will be awesome when done. I look forward to the tuning aspect of this and have downloaded and learned some free programs to do this with. Pcmhammer and tunerpro to be specific. I've built a bench harness and have been playing with removing VATS and much more. All free, no hptuners needed and I can tune as much as I want. I'll have remote start and cruise control when done which is exciting.