What should I be using in a '83 SBC?

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Remember it's basically just a 350 Chevy with a smaller bore. Same rods and crank.

Not exactly the same, the crank balancing is different between the two, 305's also had cast internals, and 2 bolt mains.


Not sure why the push for SAE30? This isn't 1983. Back in '05, I scored about 40 gallons of Delo 400 SAE30 from AZ for $.99/gal. It was a good deal and discussion back then revealed it behaved more like a 15W30 than straight weight. Still, not sure why you would not run a quality 5W30 lube in this stock 305. No extra ZDDP is going to save a physically inferior junk cam. As far as flat tappets go, there are millions of GM small blocks (and Jeep 4.0L/2.5L) engines running around on modern oil. I just don't see the value in running $12/qt oil in a 305.
 
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Cams didnt last with high zinc oils in the 60's and 70's. If the cam is soft either it or the lifter will give up. I think many smog motors had effective lift under .42" with duration under 200 and light seat and over the nose spring pressures.
If the lifters aren't rotating that lobe will be gone pretty quick. Tore down and built many SBC, BBB, and BBC over that past 1/2 century.

Timing chain will be gone by 90-110K. Worry about that. You can turn (rock) the crankshaft CCW and CW 10 degrees and look at the dist. if it doesn't move 2-3 deg you need a new chain. Big thing with 305 is crank shaft and thin wall block and low-po cast iron. Many wont take a 02 or 03 over bore.

p.s: ILSAC oil still has ZDP.
-Ken
 
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OVERKILL

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There were many 2 bolt 350's as well, but are still a different casting. The 305's are a lighter block by design (for economy).

Yes, different casting and of course much smaller bores. Conceptually the idea that it was a reduced bore 350 is correct, as they are the same architecture just like the 283, 327 and 400. But each variant had its own castings AFAIK, and so from a technical standpoint it is obviously more complex.
 
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4 barrel carb , I wouldn't use anything thinner than a 10w30. That assumes it is garaged for salt season. If that is the case then maybe, 20w50 or 30w to handle fuel dilution.
 
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I used to bracket race my 350 Malibu. It was a lot of fun building engines and running them. Here's some block casting info I have for 305's and 350's. You'll see they are all different.


Engine Block Codes for CID 305

Casting Years CID Main
355909 1976-79 305 2
361979 1978-79 305 2
460776 1978-79 305 2
460777 1978-79 305 2
460778 1978-79 305 2
4715111 1980 305 2
10046164 1986 305 2
10243878 1996-97 305 2 Vortec truck, roller cam, one-piece rear seal
14010201 1980-85 305 2
14010202 1980-85 305 2
14010203 1980-85 305 2
14016381 1980-84 305 2
14016382 1979-84 305 2
14016383 1980-85 305 2 Truck
14088551 1986-87 305 2 one-piece rear main seal
14093627 1987-91 305 2 Roller cam, one-piece rear seal
14094766 1986-up 305 2 One-piece rear seal
14102058 1987-91 305 2 Roller cam, one-piece rear seal


Engine Block Codes for CID 350

Casting Years CID HP Main
140029 1980-84 350 2
366245 1978-82 350 N\A 4 Bowtie High Tin
376450 1978 350 175-220 4
460703 1978 350 175-220 4
3858618 1968-76 350 2
3892657 1967 350 295 2
3914678 1968 350 295 2
3932386 1969 350 300/350 4
3932388 1969 350 300 4
3956618 1969 350 250-350 2/4
3970010 1969-69 350 255-350 4
3970010 1970-80 350 145-350 2/4
3970014 1968-79 350 only 200 & 255 2/4
3970014 1970-75 350 2/4
6259425 1969-76 350 2
10036033 350 4 Goodwrench crate motor, 2-piece rear seal, "Hecho en Mexico"
10051184 1986-up 350 N/A 4 1 piece rear main seal. BOWTIE
10051184 1986-up 350 4 Bowtie, 4.00"-4.155" bores, 1 or 2-piece rear seal
10054727 1986-up 350 2/4 one piece rear seal, some "Made in Canada"
10066036 350 2/4 Target Master/Goodwrench crate motor, 2-piece rear seal, "Hecho en Mexico"
10066038 1994 350 4 Goodwrench crate motor, 2-piece rear seal, "Hecho en Mexico"
10090511 1990 350 375 2 LT-5, ZR1 Vette, 375hp
10125327 1992-96 350 300 & up 2/4 Gen.II LT-1, reverse flow cooling
10125327 1996-96 350 300 & up 2/4 Gen.II LT-4, reverse flow cooling
10153558 1991-92 350 375 4 LT-5, ZR1 Vette, 375hp
10199001 1993-95 350 4 LT-5, ZR1 Vette, 405hp
10243880 1995-00 350 2/4 Gen.I crate motors and "ZZ4", roller cam, one piece rear seal
14010207 1980-85 350 190 & up 2/4 corvette
14010209 1980-85 350 4
14011064 1982-86 350 N\A 4 High Tin
14011148 1987-89 350 Roller cam, one-piece rear seal
14016379 1977-79 350 up to 225 2/4 corvette and others
14079287 1986-90 350 Truck
14088526 1987-89 350 Roller cam, one-piece rear seal
14088548 1986-88 350 205 & up 2/4 corvette and others
14093638 1987-95 350 2/4 Roller or flat tappet cam one-piece rear seal
14101148 1988-up 350 205 & up 2/4 1 piece rear main seal. Late model roller non LT1
14101148 1987-90 350 4 One-piece rear seal
 
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Yes, different casting and of course much smaller bores. Conceptually the idea that it was a reduced bore 350 is correct, as they are the same architecture just like the 283, 327 and 400. But each variant had its own castings AFAIK, and so from a technical standpoint it is obviously more complex.
Don't forget the 400 had Siamese cylinder bores. Need them steam holes for running 350 heads.
 

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Don't forget the 400 had Siamese cylinder bores. Need them steam holes for running 350 heads.

Yeah, the 400 was pretty much the limit, bore-wise, for the old SBC IIRC. A friend of mine had one in an S-10 that ran 10's or low 11's on motor I believe (been quite a few years) but wasn't very streetable.

A good friend of mine and myself, who were both SBF (Mustang) guys, his dad was die-hard Chevy, so we both had a hand in putting together the engines for his S-10, which had an SBC swap. He also had a few 1500 plow trucks we worked on, the one with a pretty tired 305 in it.

First one we did for the S-truck was a .040 over 4-bolt with camel bump heads that he had the shortblock put together by "some guy". It was never right, engine was extremely loose. I can't recall the cam that was originally in it but it ended up with a pair of World Products heads on it for a stint off the CASCAR engine in my buddy's Camaro that blew up and paired with a Lunati Voodoo. The combo worked pretty well on a 125-shot of spray.

My buddy ended up building a 355 roller motor for it (2-bolt), as he was working with an excellent machinist at the time who was very involved in the local circle track scene. We put it together with a Comp roller stick in it, had the World heads freshened and milled (springs were pretty toast) and I think we put a Vic Jr. on it? Can't remember. Had gone through a few intakes at that point. We'd tune it at the track and on the street using a wide-band and have it working just perfect and then the old boy would "time it by ear" until it was rattling like a spray paint can. He'd bugger with the carb until that was all screwed up, so we thought we'd solve that with fuel injection, so we put a Holley kit on it, but that just drove him nuts that he couldn't tinker with it and he ripped that off when we stopped working on the truck because he wouldn't leave it alone. Re-tuning it regularly got old.
 
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Not exactly the same, the crank balancing is different between the two, 305's also had cast internals, and 2 bolt mains.


Not sure why the push for SAE30? This isn't 1983. Back in '05, I scored about 40 gallons of Delo 400 SAE30 from AZ for $.99/gal. It was a good deal and discussion back then revealed it behaved more like a 15W30 than straight weight. Still, not sure why you would not run a quality 5W30 lube in this stock 305. No extra ZDDP is going to save a physically inferior junk cam. As far as flat tappets go, there are millions of GM small blocks (and Jeep 4.0L/2.5L) engines running around on modern oil. I just don't see the value in running $12/qt oil in a 305.

Balancing was different on 400 small blocks. Not 305s. Also lots of 350s also had 4 bolt mains, the 305s just didn't ever come with the 4 bolt mains. It only mattered for higher RPM. And other than high performance or heavy duty versions most were cast. Rods and crank were the same part number for the same year 305/350.

I agree about the oil, my 240k 305 has ran on modern synthetic 0w30/5w30s for the past 40k+. No issues.
 
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Balancing was different on 400 small blocks. Not 305s. Also lots of 350s also had 4 bolt mains, the 305s just didn't ever come with the 4 bolt mains. It only mattered for higher RPM. And other than high performance or heavy duty versions most were cast. Rods and crank were the same part number for the same year 305/350.

I agree about the oil, my 240k 305 has ran on modern synthetic 0w30/5w30s for the past 40k+. No issues.

I didn't bother mentioning that 350's also had 2 bolt mains. There was no need.
400 small blocks are externally balanced. 305's and 350's are internally balanced.

The 305 crank and 350 cranks are not balanced the same. They will physically interchange (they used the two piece rear seal "442" cranks) but the 305 weights were drilled more to make them lighter for the smaller pistons and lighter duty rod.
 
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350 crank on the left, 305 crank on the right.
 

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I didn't bother mentioning that 350's also had 2 bolt mains. There was no need.
400 small blocks are externally balanced. 305's and 350's are internally balanced.

The 305 crank and 350 cranks are not balanced the same. They will physically interchange (they used the two piece rear seal "442" cranks) but the 305 weights were drilled more to make them lighter for the smaller pistons and lighter duty rod.

Okay, I wasn't aware of that, I thought you were thinking of the 400 and it's external balancing.

I just remember looking up the parts on the gm system (I believe for a mid 80s 305 and 350 and seeing the same part number for rods and crank, but they could have been listed incorrectly.

I've seen a lot more high mileage 305s than 350. Probably due to less HP (although they did have higher compression ratio 85+ compared to a 350), and they didn't have the crack prone cylinder heads that many 75-86 350s did. They seem to be able to tolerate overheating really well other than the valve seals disintegrating.
 
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No that's cool. I used to bracket race my 350 Malibu and have all sorts of numbers in my head. I still run a solid lifter cam in it. I think it might be an Isky.

For what it's worth, someone GAVE me a rebuilt '94 Truck 305 (if memory serves, 175HP/275TQ?) that they never used and ended up going with a TPI 350. I'm currently fitting it to a SM465 Granny Low 4 speed and flipped Dana 300 transfercase for use in my rock buggy.

I never minded the 305. Not sure about the bad rap, but once it came out, people stopped complaining about the 307.
 
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BTW - Sorry to the OP for the Post hijack!!!

Run a quality OTC 5/10W30 or diesel oil for piece of mind and motor on in your cool ride man!
 
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I liked the 305 because it's what I had when I was 18 and extremely hard on stuff. I had an 87 cutlass with factory 305 (Canadian spec cars came with it), and then an 86 Caprice for a winter beater. I beat the hell out of them both, lots of burnouts and I broke the rear end on both and fixed them with junkyard parts but never had an issue with the engine except valve seals, especially once they got overheated.

The 85+ lg4 worked so much better than the 83 I have now (compression ratio was 9.5 to 1 instead of 8.5, not sure why). I always ran 91 because they liked to ping on 87 if I advanced the timing even a little beyond stock.

The L03 tbi 305 in my 89 Caprice was pretty doggy too but it also had 330k miles. It ran like new otherwise though. I tried to kill it when the car was too rusty to be worth fixing anymore, but it seemed to be impossible, short of draining the fluids and that's cheating.
 
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Those engines are incredibly cheap and effective to modify. If that was my car, I'd wish the cam would wear out to give me an excuse to add some power to to the engine.
 
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Those engines are incredibly cheap and effective to modify. If that was my car, I'd wish the cam would wear out to give me an excuse to add some power to to the engine.
Now that's an idea! Harder to pull a cam on a late model smogger than a '63 though. So much junk all over the engine.

But doable. Just not in 2 -1/2 hours! :)

Lunati, Isky YES.

Just say NO! to Crane.

There is my daily BIAS :)
 
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My 83 305 has 240k miles. My last one (an 89 roller cam 305 had 332k miles). I've had several and known lots of people that had them, never heard anyone say anything like that. Gutless yes, unreliable...no. Remember it's basically just a 350 Chevy with a smaller bore. Same rods and crank.

They did have camshaft issues mainly 77-83. A friend of mine has the original cam in his 77 with 330k miles though. His dad bought new.

I run 0w40 euro in mine usually because it's my winter beater, cold starts at minus 20 or colder.

If it's low mileage I'd worry more about the cam. High mileage like mine it's either had the cam replaced years ago or it's not going to fail.
Agreed about gutless. I had 305’s in my 86 Blazer and 85 Trans Am. Completely reliable and durable on Pennzoil 10w30 yellow bottle.
 
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