Trying to piece together an engine can be a sobering experience, especially when you're on a shoestring budget. We wanted to build a new powerplant for our project Elco (which we still don't have a name for), and since we're trying to keep this hay hauler on a cheeseburger allowance, that meant we needed to stay focused and to spend our green only where it made sense for us.
Our initial thoughts went straight toward a small-block; however, after a little investigating we learned we could get into a 454 big-block for a few extra bucks. The bulk of the budget was split nearly in half between the bottom end and the cylinder heads. We started off with a Larry's Track Pro two-bolt main short-block that included stock GM shot-peened rods, Seal-Pro Speed-Pro domed pistons, and a stock cast crank. Up top is where we spent a little more for a quality set of RHS 320cc cylinder heads, and between the cubic inches and free-flowing top end, there was no doubt this baby was going to make some serious power. And given that this is our Nitrous issue, there was no way we wouldn't give this rat a hit of the gas.
When it came down to D-day, we used 91-octane for all the pulls-even our nitrous hit. So what kind of numbers does a stock-style, flat-tappet big-block produce? This budgeted bad boy churned out 553 hp and 518 lb-ft with 38 degrees of total timing. And on the nitrous...well, you better keep reading, 'cause it turned out to be a nice surprise.
BREAKING IN A FLAT-TAPPET
To break in our comp flat-tappet cam, we first removed the inner springs from our RHS heads. Because of the triple spring design, the valvespring pressure would have been too much for the new cam to handle and could cause it to go flat. We ran the motor for 20-25 minutes with minimal loads and never revved the engine past 4,000 rpm. Once the break-in was complete, we removed the Scorpion rockers again, swapped in the inner springs, and relashed the valves.