Head Hop-UpQ I just rescued a '74 Nova SS from the barn it has occupied for the last 20 years. The original engine was long gone and in its place was a 350 from what I think was a truck. The engine code reads V0709TJA, and the TJA comes back as a '73 or '79 truck. The heads read 462624, which I believe have 76cc chambers. The engine runs very well with no smoke at all, but it's a real slug. I want to replace those heads with a set of World S/R Torquers with 67cc-or maybe the 58cc-chambers. Just wondering what the compression ratio would be with those heads and if I could expect any power increase. I also have an Edelbrock EPS intake and a Mallory HEI distributor that I will install at the same time. The car will not see any dragstrips, but will be driven on the street here in Southern California. Thanks.Ronald McIntoshVia e-mail
A Yes, your engine is a late-'70s truck engine. And yes, the heads do have large chambers that come in at 75.5cc, but they also have 2.02/1.60-inch valves. They were the same heads that were used in the late-'70s L82 Corvette engines. Now this may make them sound like high-performance heads, but they didn't make very much power in stock trim. Your World S/R Torquers would be a very good replacement choice. The stock engine has dished cast pistons, and with the factory specs the engine has 8.0:1 compression. If you went with the 67cc World heads it would step your squeeze up to 8.68:1, and with the 58 cc you would realize 9.5:1! That may be a little tough on our current 91 octane pump gas, but you can get away with it. As for power increases, you will see a marked improvement with the Torquers' redesigned intake and exhaust ports. As for the compression, a good rule of thumb is that you will see around a 4- to 6-percent power increase with one point change in compression. It would be very safe to say you would see at least 6 percent power with just the compression change.
While you're in there, you should think about swapping out the camshaft to a mild street grind. If the engine is as lazy as you say it is, the timing chain may be very stretched and the nylon top cam gear could be ready to fail. We would hate to see you put all that time and money into your Nova and have it die. An Edelbrock Performer cam, a Crane Powermax 260, or a Comp Cams 252 would be a great choice for your stock Nova. These camshafts will work great with your Edelbrock EPS manifold and Mallory HEI, and if you slip a set of headers into the mix you will have a 300hp small-block. Enjoy.
Oval TeamQ I am building a 454 that is 0.060 over for my '55 Chevy. My trans is a Muncie M22, the rear axle is a 12-bolt with 3.73:1 gears. I'm stuck with the early, closed-chamber, large oval-port heads, casting number 3856206 (bathtub). My goal is to make 440-450 hp with 500 lb-ft of torque. Can that be achieved with these heads? I do not know which cam to use. I was thinking about a Comp Cams 280 Magnum hydraulic flat-tappet, which has 230 degrees duration and 0.520 max lift. If this is not a good choice, could you recommend a cam, and could you also recommend what size primary pipe and exhaust system to use? Thanks for your time.Robert FuscoVia e-mail
A Back in high school, my best friend, Ron Kober, had a Pearl White '55 with an early Olds rearend, Muncie four-speed, 4.88 gears, and a 396 that had all the old parts from my dad's Fiat Topolino Altered car. We ran early ovals on that engine with a nasty mechanical camshaft (one of the old L88 Chevy cams). We had a blast with that car until the cast pistons shattered from not watching the tach! We were having too much fun.