I have a BBC motor that I have been saving for 25 years. I got it from a salvage yard out of Chevy C30 truck. Block casting number is 10069286. I am just about to tear it down in preparation for a trip to the machine shop. Research indicates that this is 1990-91 Mark IV, 454 cubic inch, 4 bolt main engine. Is there a better engine for a street car build Sunday driver C3?


Joe

 

Only thing that would concern me is if it is a tall deck truck block. Not sure if they still existed in 90 or 91, but if it is could cause some fitment problems. If not it would be an excellent engine for your C3.

Off topic, I am on Long Island in the summer and my girlfriends Mother who passed this summer lived in Franklin Square on Admont. Spent a lot of time there.

 

Any Gen 3 or 4 LS engine would be a better choice, but there are plenty of big block swaps on this Forum as well.

 

Having the torque of a Big Block Chevy engine is something hard to compare to. I have been in some incredibly fast vehicles in my life and the rush you get from the torque that pulls like a locomotive is still an awesome feeling.

The 454 is a great engine and there are plenty of parts available to build one up. When I built my new 427 I started with a old block and a matching pair of cylinder heads that fit the L88 pistons. Then I replaced every component that was not already forged and replaced the entire bottom end with forged components. I really like the 327 and 427 variants of the GM engines and especially the way they can rev so easily. The sound of a BB roaring in front of the windshield will awaken all your senses.

I heard a ZL1 run at Corvettes@Carlisle and I was hooked. I wanted an engine as close to that as possible so I modeled my engine after an L88. My C3 is a 1968 so I copied how the L88 was in 1968 trim and then built the engine. Compression is what makes my engine as much fun as it is, I was shooting for the exact match of the 12.5-1 but I ended up with 12.25-1 and it is still a blast to drive and I can even drive it on 93 octane as long as it is not July or August. In Hot weather I use a water/methanol injection system that automatically sprays the mixture into the engine and it's water turns to steam pulling heat out of the intake system and the methanol makes the octane jump up to 116 octane.

Power? No problem. Drive-ability is good as long as the roads are dry. The smile burned into the front of your face will likely be permanent from all the fun you can have. Miles of Smiles that is.

Stick to your big block and you will have fun in your C3.

 

I just ran a search on that casting number and it is not a tall deck block. It is actually a pre cursor to the GenV and GenVI performance blocks to come after. It is a 4 bolt high performance block, as you said, so would be a great foundation for your build of a nice big block. Nice find! I agree with CT, nothing like the sensation of driving a big block Chevy. I have had a few LS engines as well. That's why there is a big block in my 69!

Bill

 

The best engine is the free one. Otherwise I'd spend $4K on a Brodix or Dart SHP block.

This means you can now spend $1,500 in the machine shop doing everything. without cutting corners to make it perfect before you start.

Build a 496 if you need to overbore. 650 HP and torque on 91 octane pump gas at 5,800 rpm......on 87 you'll still make 575........good luck !!

 

I've built several big blocks, gen 3,4,5and they all make good power if you use the right heads. One mod I would def reccomend is machine it for a 1 piece rear main seal. Then use a 1 piece oil pan gasket also.
= no stains on the garage floor.

 

Double ck that it has a fuel pump boss and clutch linkage pivot ball hole if you need it.

It will make a great engine. As mentioned...if for whatever reason it needs a crank...go ahead and build a 496....won't cost any more. It all bolts together.

The power is always in the heads. A nice set of ported iron oval ports can run great....but if the budget allows for aluminum...the sky is the limit along with another 50-100 HP with ease.

Get the right cam and you'll be in business!

I've never had any leak issues with 2 piece rear mains. I like the one piece oil pan gaskets...but the normal stuff on a big block will seal up tight too.


JIM

 

Spend all your money on the heads...Brodix or AFR are llike magic to these big blocks.....instant performance. I had a 396 that had a big cam and it had the original 100 cc heads and 10:1 compression. My 427 lost a bearing so I threw the 396 in the car. I was running the same cam in both engines and the same intake. That 396 sucked. It was a dog until I threw the Brodix heads on it. Went from 10:1 all the way down to 8.5:1 compression. I was disappointed in that news but tried it anyway

it was a totally different engine. Loved to rev and would spin the tires just flooring the go pedal!! Spend the money on new heads. You will save 100 lbs and you can lift them without needing a major massage afterward

 

And what belt system are you going to run. March has a good looking low profile one for corvettes. I was considering that. If you want stock, start looking now as the brackets and pulleys can be hard to come by fo rorigianl equipement if you want to be certain they will fit. everything else will fit

 

I have the same block.
It does have the provision for the mechanical fuel pump and the manual clutch pivot bolt.
I built a nice street-able 496 which puts out 570 ft lbs torque at 4800 rpm.
Keep in mind that adding much over 450 hp/tq that you’ll need to start upgrading all your drivetrain components.



I went with a Concept One serpentine belt system for mine.
Really nice quality.

 

It's really all in the heads. Peanut port BBC heads are great for toque, but **** for much else. Imho. A good set of ovals or rectangle port heads will work nicely. Go aluminum, if it's in your budget, just for the weight savings.
i would bite the bullet and convert to hydro roller lifters and cam . Just my .02
good luck.

 

I have been running a pair of Brodix Race Rite oval port heads on a 489 cu in 454 4 bolt based engine in my M21/3.08 rear end '68 for 15 years now. Cam is a mildish flat tappet Howards hydraulic. Intake is Performer RPM Air Gap with 950 DP (a bit oversized perhaps). Last dyno showed 606 ftlbs @ 3850 and max hp of 570 @ 5800. Power band runs from 1200 rpm through to 6000/6200 (falls flat after that) - on a cruise 15/16 imperial mpg is possible. Can be a little 'tetchy' perhaps in hot summer city use. The wide torque band is very addictive, fortunately the drive-line has held together so far.........

 

Sounds like it is a 4 bolt main block. It is not needed, really, for anything resembling a street motor, as a studded but 2 bolt main big block can handle 600HP. But the 4 bolts are even stronger.
I found conflicting information online as to what the rest of the engine is like. If out of truck, and original, it would have horrible low rpm peanut heads. Check and see if it has a 3 letter code in front of the pass head on the "pad".
That block may also have been used for LS6s and LS7s of the era, the over the counter ones. It should be very strong. It may even have some neat features, as mentioned in this write-up, even if it came out of a truck, the block should be the same.
What really matters is, does it have a forged crank, and is it useable? Forged cranks will ring like a bell when tapped. And you can examine the casting lines, or numbers.
Put good forged rods & forged pistons in it, and it will handle whatever you can throw at it. 600-800-1000HP. The block will not be the weak link. Your corvette driveline will. 500HP is simple with a BBC.

>>Real story behind BBC casting number10069286

Yes this is a 1990 4 bolt main mark4 454 High performance block sold over the counter at gmpp. They were a 1 per person only. A crate engine outfit could not purchase one. In 1989 the gmpp guys where looking for new a headquarters out back of the GM. property. They went in an old building. And in a corner office that was Locked up they found all the thought to be lost forever casting molds ect... From the 1972 LS-7 454 that was suppose to come in 1973 stingray but didn't. They got the okay to cast 700 LS-7s ,they did some research and addressed the weakness's of the original block 10069286 is what they came up with The baddest toughest mk4 ever cast only one rated for 1000 plus HP only one with Siamese cylinders with 3 1" slots machined between cylinders for coolant flow, only one w/ 5/8 shanked main cap bolts, wich by the way mine has CAT bolts. When they were done R and D came and took there modified mold and formulas for research and the new generation 5 and 6 eng. Are based off of 10069286 wich kinda makes it the grandfather of the new 572 crate motor and all gen 5 and 6 blocks. I read this in an early 90 S copy of hot rod magazine. <<

 

Just be REALLY careful when choosing a crank for your BB engine. Knowing that they made Cast and Forged Crankshafts for these beasts after 50+ years. Most of the "used" GM cranks out there have dozens of small stress cracks all over the bottom end.

The crank I had was not worth doing anything with, as it was one of the worst I had seen under magnetic testing. As I purchased almost a dozen used Forged Crankshafts made by GM and every one of them had cracks all over the place. I was shocked to find that many stress cracks on the important places/surfaces of the crankshafts. I would not take a chance on any of the cranks because I wanted a High compression 427.

One speed shop owner even told me that "I should use one of the forged cranks (with stress cracks) as I wouldn't stress it enough to hurt anything". NOT in my engine. I ended up going thru so many cranks shafts to find ONE perfect example with Zero cracks. I would be very careful when looking at building your beastly BB. It might be more expensive but if you go high horsepower BB you will need a good solid block and a crack-free Crankshaft possibly from the aftermarket.

For me and my beastly 427 Forged parts were used in the short block.

 

I used a SCAT Stroker kit with a forged crank.
My engine builder has been around for decades and is well known in the racing industry.
He was able to call SCAT and build the stroker kit with the parts he wanted included in the kit.
It was more expensive than their standard kit, but he put it together using quality components.

 

My engine builder had been working on the CanAm cars of the 1960's and he knew his Porsche engines along with Fords and GM's. He was building engines professionally for many years before re-locating to Virginia.
We looked at SCAT and other aftermarket cranks but there was some particular reason why he wanted to use a factory Forged Crank. Back in the early 1990's the parts for the 427 were much harder to find and more expensive, I wish I had the Internet back then. There were several modifications done to the crank after we found a "perfect" crank by the machine shop. My rods were not original GM parts, instead we used an I-Beam style Forged connecting rods. Using his specialized tools he weighed and matched every component as he was assembling the engine. Watching him assemble the cylinder heads is where his attention to detail really came out.

Being a Newbie to a 427 BB I wanted to have him help guide and teach me as we went along building the engine. My buddy was OCD most likely as he spent so much time on the details and there was one way to do things, the "Correct" way. I learned so much from my buddy as he slowly and methodically assembled my 427. I was very lucky to find somebody like my buddy Rick as he was a great teacher of High Performance. He died of a Heart Attack shortly after, he is missed.

 

Nice. What brand and size headers are you running?

 

Way to soon for headers. A BBC in a C3 is not really an engine swap. More like an enhanced remove and replace. Planning on using as much GM parts as I can. I have a set of big chamber rectangular port heads. Most C1-C3 Corvette's only have to sound bad and go hard through 2 gears. Sunday driver deal. This'll be a fun project.


Joe

 

The big chamber rectangular port heads make for nice bragging rights, but may not be the best choice for your build, unless you’re planning to run it strictly on the race track with high compression at high rpm’s.
If your building an engine for mid range torque and top rpm under 6000 rpm then a better head combination would be heads with oval ports and the combustion chamber to match the rest of your engine build.
Those big chamber rectangular ports will kill your performance at lower and mid range rpm.