Building My 383: How It All Began…

I have now driven the brand new 383 for a couple of months and I decided to begin writing articles from the beginning until the very end of the project to help others with their engine build ideas and also help them actually build the engine from scratch. I was no engine mechanic and I had never built an engine from scratch before. So my stories should be especially helpful for guys like myself.

When I bought my 79 Corvette almost five years ago I never thought I would be building a more powerful engine for it myself. It was my first true American car and at first it seemed like it had more than enough power. 200ish hp, you’re kiddin’, right? :) But that’s how I felt at the time. Driving the 4-speed manual with a V8 was already a challenge for me and I enjoyed it a lot for the first two years. Unfortunately the engine was problematic from the beginning and on the first drives I already experienced upper radiator hose blow-offs and couldn’t figure out what was wrong. The radiator cap was OK, all fluids were clean but the radiator hose went stiff like a tire as soon as the engine started up. It didn’t seem perfectly normal when comparing to some other engines. I secured the radiator hose better and I didn’t experience any more of these issues. The pressure still kept sitting in the system for the next few years. I decided to make a small upper block overhaul two years ago during the Winter when I removed the intake and the cylinder heads. I sent the heads for a checkup and rebuild and it came out the heads had cracks in the cylinders towards the coolant channel. I found out by the casting numbers that they were crack prone heads anyway so I decided to acquire something else. I was able to acquire heads from a 5.0 (305) Chevy engine with 58 cc chambers. I had these overhauled and tested and since they came out fine, I installed these on my 350 engine. I know the compression ratio was somewhere between 12-13 and that’s a lot! I had to run on the highest octane pump gas (98 in Europe) hoping it won’t detonate. I also installed the Edelbrock Performer RPM intake manifold to pump up the power. The engine was indeed more powerful when I tried it for the first few times.

I drove last Summer with that engine but although the engine had been puffing some blue smoke already from the beginning, the new heads didn’t help it and in the middle of the Summer the spark plugs began getting real dirty and full of oil. Oil on a Spark PlugIt meant that certainly the oil rings on the pistons must have been quite worn out. Soon also at least one of the cylinders quit working properly meaning that I felt power loss and we finally measured compression loss in two cylinders. I still drove the Corvette until the end of the Summer when I suddenly heard sounds from the engine as if something was flying around inside the engine and causing a random clacking noise. That’s when I decided to put it away for Winter and see what the heck is going on.

I wasn’t much of an engine guy a little less than a year ago but I was eager to learn all about it and that’s why I never wanted to send the engine to a professional mechanic. In the beginning of last Winter we removed the top end of the engine (the long block) and found extreme oil dirt from all the pistons. We lifted the engine off the Corvette using an engine crane and put it on the engine stand. When we began taking it all into pieces we figured out that there were lots of metal pieces inside the oil pump pick-up element sitting in front of the filter plate. 79 Corvette Engine - Broken Cast Piston Due to Piston SlapWe quickly identified these pieces to be parts of at least one piston. When we removed the pistons and rods we saw two pistons with piston skirts missing and some other minor damages. Most probably the pistons were destroyed due to the so called piston slap which means that the cylinders had worn so much larger that the pistons were not moving precisely in there anymore but slapping on the cylinder walls causing vibrations and finally damages to the pistons.

That’s when it became clear that a full engine overhaul was imminent and if I wanted to drive the Vette next Summer, I had to do something quickly. I began reading about engine overhauls and consulting with my friends who knew more about these things. Soon I decided that there’s no point just overhauling the engine with stock parts but I should be building it more powerful as well one way or another. My goal was something around 350-400 hp max and I started asking stupid questions in the Corvette Forums and other places on how I could achieve it as affordably as possible. Everybody ofcourse told me that it all starts from letting a lot of fuel-air mixture into the engine and also out from the engine, meaning good intake and good exhaust. It was a bit easier for me on these things since I already had the Edelbrock Performer RPM intake and full length Hooker ceramic Competition headers with side exhausts custom built a couple of years ago.

Somehow I started e-mail exchange with a well known Corvette engine builder Jim Barth from Salt Lake City, USA who gave me some real good advice in the beginning and explained all the details I wanted to know. He told me that ofcourse the key for power is proper cylinder heads and a good camshaft which works with the rest of the combo. Jim and also others in the Corvette Forums began suggesting to buy Air Flow Research (AFR) heads since they are probably the best street heads available for a small block. Jim also told me that I would be looking into the 400-450 hp range with the AFR heads and a 350 (or 355 when overhauled) engine. It sounded like more than enough for me and I was eager to start putting together the parts list. Jim found out that I was going to order new pistons anyway so he seriously wanted to know why I’m not going the 383 Stroker route but instead opting for the old fashioned 350. At first I found that the 383 stroker kits are a bit out of my league finance-wise (remember, I’m living in Europe and parts end up nearly twice the price of USA) but when looking at the prices again it became evident that it might not be such a bad idea after all to invest a bit more and build a 383 instead. I started to browse for stroker kits in Summit and other stores. I found a Scat stroker assembly for around 1100 bucks which contained forged pistons and rods with a cast crankshaft. I was almost ready to buy it until I met another guy – Mike Lewis.

I will continue telling the rest of the story very soon!

Had to Transport the Vette

1979 Corvette C3 Stingray Being Transported on TrailerThe Vette had been sitting in my home garage for the whole winter since last September or so when the engine decided to end the partnership with me. Since then I decided to build a new engine for it and the Stroker 383 project is going to be ready quite soon. I will write more about it in a day or so. Anyway, since the home garage is just a bit too low for proper engine lifting and there isn’t much room to work on the engine when the car’s inside, we decided to transport the Corvette to our countryside where we have a much larger garage and an electric winch in the ceiling. I was a bit scared of the transportation process since I hadn’t transported the car before on a trailer but the process went unbelievably smoothly. The guy who helped us out with the trailer was really familiar with his job and the Vette was on the trailer in no time. I just had to make sure before that all the stuff loose in the engine compartment was secured not to loose any parts in the wind on the motorway. The Vette is now safely in our countryside garage and I am ready to build the engine at home as soon as all the parts are ready.

The engine block is currently being bored, honed and cleaned with new cam bearings installed also. They promised to get it ready for today but I guess that’s not going to happen so I have to wait until the beginning of next week. Basically all of the parts are here except the AFR heads which had a really long delivery already inside the States and still have to fly all the way to Estonia. I really hope they arrive within 2 weeks. The other parts I still need are the pushrods which I have to measure once the engine is almost assembled up to the heads. Then I will place a quick order from Summit to get them here as quickly as possible and finally finish the engine assembly.

1979 Corvette C3 Stingray Being Transported on Trailer

1979 Corvette C3 Stingray Being Transported on Trailer

Parts Combo For My Chevy 383 Stroker Engine 460+ HP

The parts list for building the 383 stroker engine for my 79 Corvette has now almost come to its final state. I must say that choosing the right parts has really been a pain because there’s just so much to choose from and every part needs to be Googled and checked through the forums. My friend Jim Barth from Salt Lake City, USA has given me a lot of help to build this 383 stroker and a lot of credits will go to him once the engine actually fires up. I certainly recommend him to anyone who wants to build a powerful 350 or 383 or any other Chevy engine.

SHORT BLOCK

Now here we go… first of all the short block. I took the original Corvette L-48 2-bolt main SBC 350 block out of my car and cleaned it up and removed all the original parts. The block was showing the usual wear on the cylinder walls and no factory honing marks were present anymore. It was as shiny as a mirror and also remarkably wider than it should have been originally – caused by the pistons over the years. Fortunately no big damages so I have sent the block to an engine shop where they will bore the original 4.0 inch cylinders over by 0.030 inches which will make the cylinder bore 4.030 inches – the proper bore for a Chevy 383 stroker engine. SCAT 383 Stroker KitThey will take care of the block and will also deck the cylinder head surfaces on the block by around 0.02 inches to make them straight and even and clean of all the old gasket remains etc. The important question now is what to put inside the short block – talking about the crankshaft, rods and pistons. The easiest way was to get a fine stroker kit which already contains all the important parts. I decided to go for the SCAT 383 stroker kit, already internally balanced in the factory with the included parts. The kit also contains forged pistons, the crankshaft is cast metal. The problem here in Estonia is that nobody properly balances a V8 engine and that’s why the safest way for me was to get an already balanced rotating assembly kit. In addition to the main components the package also contains piston rings, ARP rod bolts, oil rings, main bearings and a few other important components. What the kit doesn’t contain are the main cap bolts which hold the crankshaft in place – for these I have also decided to go with ARP’s. I’m yet to decide whether to get the standard strong bolts or studs.

The next important thing is ofcourse the camshaft. First of all, one needs to decide whether to go for hydraulic flat tappet (the factory standard for First-Gen small blocks), hydraulic roller lifters or solid roller lifters. I will write another article on the difference between them just to make it understandable also for the beginners (like I was a few months ago). However, since the hydraulic roller kit is 2-3 times more expensive than flat tappet and gives perhaps about 20-30 hp extra in my setup, I have opted for the hydraulic flat tappet solution this time. I can always convert to hydraulic roller set-up in a couple of years when I feel I need the extra power.Comp Cams Kit When choosing the camshaft you need to consider the intake duration and exhaust duration at 0.050 inch lift. You also need to think about the valve lifts and lobe separation. It all depends on the components you choose and cannot be explained in one paragraph – it’s always easier to ask people’s advice in the forums like Hotrodders, Chevelles.com and Corvette Forum. In my scenario the perfect camshaft would be the COMP Cams Xtreme Energy 230/236 camshaft with grind number CS XE274H-10. When deciding on the valve lift the cam provides you need to consider the max. valve lift available on the particular cylinder heads you get. With AFR heads it’s 0.690 inches and the hyd flat tappet only lifts to 0.490. Plenty of room there and the AFR would actually feel more comfortable with hydraulic roller cams which lift the valves more. The 230/236 camshaft also provides the nice choppy idle while giving enough vacuum out of the engine to power the brakes and suck enough vacuum into the reservoir found on the 79 Corvette to lift and close the headlights.┬áThe particular kit from Summit comes with the Comp Cams lifters and double roller timing chain and gears.

Another thing to replace inside the block is the oil pump. After doing the research in the forums I’ve figured out that Melling makes the best budget pumps. For such engine it’s also important to get the high output version. There are stories that Melling’s pumps used to be good in the old days but a few years ago they changed their castings to cut on costs and this resulted in cracked and malfunctioning pumps. People still say that they’ve recently gotten rid of these issues and these pumps are anyway the best to get.

Melling Oil Pump SBC

All the bolts on the short block as well as the rest of the engine should be replaced with better ones, preferrably ARP produced bolts.

LONG BLOCK

Now the long block part which means everything above the block itself – cylinder heads and intake. I have decided to go with the Air Flow Research AFR 195 cc Street Eliminator aluminum heads which are pretty much the best on the market today for such an engine. They do cost more than the Trick Flows and even more than budget stuff like Darts, Edelbrock lower end aluminums, Patriots and such. The AFR’s produce more horsepower and torque in the end so the extra few hundred bucks might be well worth it. The AFR heads also allow for 0.690 inch valve lift so they are perfect with hydraulic roller camshafts to get the maximum out of the heads. The valves on them are 2.02 intake and 1.6 exhaust. AFR SBC 195 headsThese AFR heads already come CNC ported from the factory and there are people who port them even better to achieve the maximum performance. But note – when choosing the heads you need to check on the intake chamber size – 195 cc is the optimum for a street 383 stroker engine and 180 cc is better if you build a 350 or 355. The larger these chambers the more low end torque you sacrifice to achieve more horsepower in higher RPM’s. That’s cool if you go to the strip. But on the street you don’t want to keep the revs up all the time. That’s where the lower cc heads come into play. The 195 cc heads are perfect for a street 383 performance engine to provide the best of both sides – lower RPM torque and 6000+ RPM horsepower. Another factor on cylinder heads is their flow. This is different – the better the heads flow the more power you get in the end since the heads won’t be limiting the fuel mixture getting into the cylinders. That’s where many of the cheaper heads lack the good numbers. When buying cylinder heads it’s possible to get them in bare configuration or factory assembled. Bare means that you only get the heads and none of the springs, valves and other stuff that need to be on them, too. Assembled heads come with valves, springs and installed valve stem seals. Everything is assembled already for you and you just have to bolt them onto your block. This is the better solution in most cases unless you want to go with some specific components. Assembled heads are often cheaper than to order the stuff and assemble them all by yourself.

The hydraulic lifters come in the camshaft kit from COMP Cams. The lifters need to drive the valves on the cylinder heads and there you need to get a set of new pushrods. Jim Barth recommended the Trick Flow 4130 chrome moly pushrods which retail in Summit for about 120 bucks for a set of 16. You can ofcourse also buy new rocker arms but I believe I will stick to the factory ones since I won’t be revving the engine too much and the roller rocker arms are still very expensive. These are easy to replace items at a later time so I better leave these for the future.

To get the most out of the Chevy 383 stroker engine you should get a fine intake manifold to complement the great heads. Edelbrock produces pretty good aluminum manifolds and they can be bought for fair prices. Edelbrock Performer RPM intake is a good one although the Performer RPM Air Gap is even better. I couldn’t get the Air Gap because it’s even higher and won’t leave enough hood clearance with the 79 Corvette.

At this point I’m leaving the repaired Rochester Q-Jet 750 cfm carburetor on and I will get an electric choke add-on for it. I will also leave the factory HEI distributor in its place. Since the new engine will be revving a lot better than factory and there’s a danger to over-rev it and cause damage, it’s the best to get a rev-limited distributor. If you stick to your stock HEI like I will, you can get a special RPM limiter module from MSD or other ignition system producers. Better be safe than sorry, you know.

I am still about to decide what kind of flywheel to get since I’m building it for the 4-speed Super T-10 manual transmission at this point. I will write another article about it soon when I have gotten some more information and won’t be telling lies to you. Since my engine will be internally balanced, I need to get the harmonic balancer and flywheel to be zero-balance. The harmonic balancer will be probably SCAT Powerforce Series 8000.

balancer sca-d-80020_w

I will soon write some more articles – first of all some clarifications about different camshaft and lifter set-ups and once I have the proper information, I will also tell you about the flywheel choice.

Need To Decide What Cylinder Heads To Buy For My SBC 350

We’ve been having a discussion in the Corvette Forum on my engine project and it’s now a fact I need to get some aluminum cylinder heads to complement the rest of the engine. I ofcourse want the best ones, but I need to stay within a budget. I’m trying to acquire a pair of assembled cylinder heads for around 1200 bucks. They can be slightly used but they must be a good brand. Can be Dart, but I prefer AFR. An important factor choosing the heads is the intake chamber volume rating which needs to be around 180-200 cc in my case. The larger engine you have or the more HP you want at high RPM, the larger cc you need. However, in my case I don’t want to RPM too high (just around 6000-6500) and the engine is 350 and maybe 383 later in a year or two. When I get too big chambers like 230 cc or so, I will donate a lot of the low end torque which is important when driving on the street and perhaps not gain that much extra HP since I won’t rev it very high.

Click here to read the Corvette Forum post