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. It 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. We 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!