But if this is not the case, and the decision is made to build or acquire a new motor anyway, the “why” question can be legitimately asked. For some, the easy answer is a cavalier “why not”, and that’s all that needs to be said, especially if the new motor will have a substantial power upgrade.
This is the situation I am currently in with my Tiger. I have made a host of decisions about what the new motor will “be”, starting with a basic use profile, which then points to what power and torque numbers are needed, which then directs all the decisions around the parts and machine work that flesh out the overall plan.
Fair enough. But when I sat down to write this article about the build, I found myself wanting to answer the “why” question. And why was that? Partly because I like to get maximum use out of the things that I own. And also, I like the motor that is in the car. It is a stock 260 with unknown mileage that doesn’t smoke, but does spray some water through the exhaust during max throttle. The oil is shows no signs of water intrusion, and the car does not overheat, so I suspect this might be a leaky intake manifold gasket. This makes even more sense when you consider that I was the guy that installed that manifold a few years back when I replaced the lifters. The 260 produces good, but not great power. Apart from a semi collapsed lifter when I over-revved it at an autocross, it has done nothing but run. It has never overheated, never given me reason to do anything but continue to drive the car, in spite of repeated floggings. It is the original motor that came in the car, and it is doing its job perfectly after 14 years and 35,000 under my right foot.
Still, it is time for the car to get a power upgrade, and I am lucky enough to be able to afford it. So, sometime in the next few months it will be with great respect and veneration that the 260 will be parked on an engine stand in the garage, awaiting a future owner’s desire for a 100% original, number-matching Tiger. In its place will go a 5-bolt, .030 over 289 with 302 internals, AFR 165 aluminum heads, and roller camshaft, lifters and rockers. Obviously, this will be a power upgrade, and my intention is to remove all the inevitable speculation, and dyno the motor prior to installation.
The block is at Ellsworth Machine in Mountain View, awaiting the rotating assembly that is coming from Eagle in China so that we can bore to the specifics of the pistons. The roller cam is a standard grind from Competition Cams, 230/236 duration at .050, with .513/.529 lift with 1.6 rockers. This is a bunch of cam, but with the added efficiency of the roller technology it shouldn’t (theoretically) shake the bumpers off the car at idle. I guess we’ll see about that.
Next month I will provide an update, and go into the rest of the decisions; intake manifold, carb, timing chain, flywheel, balancer, etc. So, cross your fingers, light a candle for me, and question my decision-making and sanity. It will be the first motor build that my friend Tim Erskin and I have done since our drag racing days. I am about to replace a perfectly sound 260 with 5-bolt roller. Why? Like Scotty in Star Trek, I am a fan of morrre powerrrrr. And, well….why not?