Is this where the engine serial number should be?





JT

 

Yes, clean it off with a old toothbrush & WD40; don't use metal.

BTW, there once was a Siegal-Robert auto parts plastic injection molding plant near Poplar Bluff.
I know SRI changed names w/ a merger. Is that plant still operating ?

 

There was 3 plastic injection molding plants in Poplar Bluff at one time. The last one Revere Plastics closed up about a year ago. I did a lot of work for Revere over the years.

JT

 

In addition to its HQ at STL, SR opened a plant at Farmington MO; was there to complete docs in advance of ISO-QS 9000 audit-cert. Became acquainted with a couple there, who IIRC, were commuting from Poplar Bluff. John & Donna Montgomery. Worked daily w/ Donna. Good folk, all. Jeez, been 20 years. Truly enjoyed my time there; except for the meth epidemic wrecking so many families & local economy. Hope that's all in their rear view.

 

To answer the original question, yes that is were the engine information should be stamped, but it wouldn't be a serial number. What should be stamped on the pad would be a VIN derivative (a portion of the car's VIN) and a code for the engine assembly date, the engine plant and an engine suffix code (engine designator), but even after blowing up the picture I don't see anything stamped on that pad.

A blank pad might indicate an engine that was "decked" (the block cylinder head mating surface was machined smooth) while being rebuilt, or a new Chevrolet bare block was installed.

Off topic, is Missouri big a plastic molding area? I have a step brother who is a tool maker for a plastic molding plant in MO, I can't recall the name of town right now but it's about an hour from Branson.

 

When Briggs & Stratton was the worlds largest producer of small engines here in Poplar Bluff it took quite a bit of support companies to supply them and many were local to Poplar Bluff. B&S almost went under but got bought out and now are much smaller and making a profit and the workers are happy.

On topic, the reason I asked about the stamp info is trying to determine if I even want to bother tearing the engine down for a rebuild or just order a Blueprint and be done with it. The engine after replacing the carburetor, plugs, plug wires and rebuilding the distributor does run but it smokes for a bit when starting it cold. After it's warmed up it settles in to a smooth idle of 800 RPM according to the tach. The odometer shows 94k miles. I remember with my 81 C10 Custom Deluxe that I went through 3 engines with that truck.

JT

 

Sounds like the valve stem seals are bad. Cheap thing to fix when you get time.

 

I cannot resolve any stamping either. To me, pad appears as either very dirty, Or, what may have been stamped, has since been obfuscated / obliterated.

One of the pioneers in plastic injection molding was Siegal-Robert, which began near close of WWII as a privately held Family operation at St. Louis MO.
It maintained HQ at STL for decades. Through a series of buyouts and mergers and reformations the face and HQ has changed;. I think it's fair to say that, at one time, Missouri was a leader in plastic injection molding; certainly as supplying OE automotive manufacturers.
? Got a twenty year old US made pickup? Pull the grille and its emblems off, and you'll likely find 'SRI' in tiny, raised characters hidden here and there; perhaps also some characters identifying molds' cavity numbers as well (re: quality & traceability). Many of the OE exterior plastic corvette emblems were made by SR/SRI. Somewhere, I probably have an older revision engineering drawing or two of same (of course None were C3; all were later).I last worked with the family in 2005.

 

I actually have the tools to do that job with the heads on the block... the spark plug quick disconnect is home made.

JT

 

some cord (e.g. lawn mower pull cord), fed into sp hole and then motor rolled to TDC for that cylinder, works well to hold valves up and is probably less prone to failure.
Many times, valve guides are also badly worn; the wimpy OE Square O-ring VS seals can't keep up, even when renewed. IMO, it's easier to feel valve stem 'wobble' when using cord, rather than air.
In that case, a reasonable solution is tantamount to belt & suspenders. Install new O-rings, in tandem with a set of rubber umbrella 'shedders' which clasps onto stems (just below retainers) and rides stems up-down as valve opens-closes. Some are made of fluoroelastomer (aka Viton brand) rubber material which is very durable while heat & oil resistant. Much better than NBR or EPDM.
A very good NON-DIY repair is to have shop service those OE iron heads' guides with a Thin-Wall, Bronze alloy Liner. Popular name in those is 'K-Liner' ... many shops have K-Liner capability and tooling; some do Not. It is far superior to having those iron heads fitted with entire valve guides; that fails and heads crack and nose of replacement guides wrecks port flow. Excess K-Liner is easily trimmed away; with No port interference.

 

If the heads need work and the rest of the motor is not already 0.030" over I'll just put a set of aluminum heads on. At this point if the block has been decked it's probably been bored so not a candidate for rebuilding.

JT

 

I can't be so sure of what I'm seeing. Has your stamp pad been adulterated or altered ? Can you resolve a pattern of very fine broach marks across entire pad ?

if you haven't already, suggest perform compression tests AND leak-down tests on All cylinders, BOTH with And without oil. To help determine condition of ring seal.

FWIW, although they're offered; +0.010" oversize shelf pistons are seldom seen. OTOH, plenty of +0.020" oversize shelf pistons offered and installed.
If at +0.020" there'll be plenty iron remaining for either +0.030" OR +0.040" shelf pistons.

Have you considered acquiring a later '86-up One-piece RMS viable block or core motor that either has OE roller lifters Or can be readily fitted with em ?

 

I can't see any stamp marks on the stamp pad, I would think they would be at least 0.010" deep and the pad looks perfectly smooth to me except for the rust in the middle if I blow up the photo a lot. I'll get in there with my dremel and see if I can clean that off.

I don't know what a '86-up One-piece RMS viable block is. From what I've seen on this car Bubba spent a lot of time working on it so not much surprises me any more on this car.

Ok, google tells me that 1986 to about 2000 small blocks have a one piece rear main seal... interesting.

JT

 

One thing that keeps me thinking about a Blueprint is $4899 for a 350 long block delivered to my door and I have the new manifold and carburetor to bolt on that block. I've been spending way too much time just getting the suspension and brakes back to oem it seems. I really thought I'd be driving it now...

JT

 

A viable block is one that is Not so damaged Nor so heavily-worn that it cannot be readily re-machined and rebuilt e.g. NO CRACKS or HOLES.
A viable core motor is entire Used long block (assembled heads, rotating assembly & block; all intact) in suitable condition for rebuilding/ remanufacturing. Usually No brackets/pulleys. THIS will form the foundation of a fresh start.

True, '86-up Gen 1 sbc have One-piece rear main seal & specific, concordant crankshaft AND is also machined to accept OE roller lifters and OE roller camshaft (this is a Big plus as it eliminates present-day frequent flat tappet failures) AND OE-type roller lifters are considerably less expensive than retrofit roller lifters)

Perhaps helpful in choosing a used motor that's suitable for a performance rebuild; following is not intended as an absolutely complete reference; it's solely guidance:
Popular motors like above include iron block-iron head "Vortec" 350 rpo L31 found as OE in only GM light to medium trucks, vans, commercial chassis and Escalades with Eighth character of VIN an "R". Mercury Marine Mercruiser and other watercraft also use L31. Many heavy genset also use L31 as do many commercial/agricultural well water pumps. Also, Many GM aka Chevrolet Performance-branded crate motors are based on rpo L31; including ubiquitous circletrack race 602. Hotrodders often find their "prize" in an old rusty or wrecked pickup/van from mid-nineties. RPO L31 350 vortec block casting number typically 10243880.
One iteration prior to L31 are also Gen 1 sbc, and includes similar rollerblocks, likewise found in light to medium trucks but Also in some of the last large RWD passenger cars. Three additional preferred block casting numbers include 14011148 and 14088526 and 14093638.

Suggest a hard pass on any Gen II sbc, because most Gen II parts (except crank-pistons-rods) cannot interchange with Gen 1 sbc. Heads and Blocks and Distributors will Not & cannot interchange.
.
building or having a motor built takes time; no way around that.

For some, the easiest way out is a crate. GM/Chevrolet brand new crates are my preference. The other popular brands don't even bear my mention.

 

@Rebelyell that's a lot of good information, thanks for sharing that.

This L31 is priced right but don't know about shipping. It was the first one to pop up.

JT

 

Free Shipping ! specifies that near top of GM dealership Gandrud's display ad, which you had linked.

Bear in mind; that's a bone stock, but brand new L31 replacement motor. As such, it makes About 255HP sae NET with Single exhaust, all belt-driven accessories and catalytic converter.

When tested on an engine dyno with open headers, a well-tuned carb and distributor, it will make About 315HP sae GROSS (sae gross is same rating parameter most aftermarket motors use to describe; including Chevrolet Performance Products).

And, just a little more cam will easily bump that to beyond 350HP sae Gross.

That other L31 version (higher-priced, but Heavy Duty), ships with hardened exhaust valve Seat Inserts. Both of em ship w/ 4-bolt main caps and Forged Steel cranks.

I wish it weren't so, but myriad variables prevent any reliable, linear correlation between SAE's NET and GROSS power rating schemes; guesstimates only.

*In about 2022, CF member Onaqwst did eventually choose the brand new L31 replacement long block option in concert w/ more cam; much of his saga linked here:
https://www.corvetteforum.com/forums...e-block-2.html
It's a long slog even Before he arrives at L31 decision. At that time the motor had different GM P/N and much lower $3600 price. But, It IS the same motor you're considering today, GM simply changed P/N and raised prices. Perhaps message Onaqwest for further opinion/guidance ?

 

WTF, I just spent an hour collecting data on the two engines when I pressed Post Quick Reply it disappeared!

JT

 

Was in heavy urban traffic earlier and while dawdling, I took note of bumper sticker; seems appropriate here.
sticker bore a silhouette of some form or another of a figure in a cross-legged Yoga pose.
immediately below silhouette is large caption SIT HAPPENS.

as it would happen, I hadn't the presence of mind to snap a pic.

 

It was something to do with the new verify I'm a human thing... how annoying that is.

JT