I dunno what type of engine you might be building that this type of specification interests you. I only have experience with street combos, and ZERO experience with the 273. So, I urge you to give an ear to the guys that do have 273 experience.
on that note;
IF:
1) that 288 cam was at Zero-lift, and I doubt it was, and
2) that cam was on a 108LSA
Then, that cam is messed up for street, and;
installed at split-overlap it would look something like this ;
288/107/111/284/70... which is;
Intake/compression/power/exhaust/Effective overlap, and
with an Ica of 73*
In a 273, on the street, with a clutch
it would need 11/1 Scr, just to get moving, because, in the low rpm range,it would make power like a slightly warmed up 225slanty. It would need to go into a lightweight car with a lotta gear. The cam wants to make it's power at say 5800 rpm,to be shifted at around 6200,
But I doubt you could get the 1960s era heads to go there.
But if you could, with the typical 3.55 gears, and 25.5" tires, at WOT, that would be 50 mph in 2.66 Low gear/69 in Second.
But at 32 mph, the rpm will be in turtle-slow territory, namely;
2870 in Second/3980 in First. With a 5800rpm powerpeak, you might expect a torque peak around 4300, so at 3980 that little 273 engine with that big 288 cam is struggling to get back up on the power. I guarantee you, that will be frustrating; more so in Second or Third gear.
But like I said; I doubt the actual lift after lashing will be anywhere near 288/284
Sometimes, mechanical cams are advertised at .020 tappet rise. and the lash might be .020 on a cam like that. But the lash is measured at the valve, whereas the lift is at the tappet. So you cannot even get a sliver of an idea as to what the actual duration of that cam might be.
What I mean is this;
.020 tappet rise, on the other side of the 1.5 ratio rocker-arm is .020 x 1.5= .030 rocker-arm motion.
IF the lash was .030. then NOW you are at zero-lash and zero valve motion.
but if the lash was .020, then the valve is already .030 less .020=.010 off the seat. But how much duration was used up in this exercise, is anybody's guess.
What if it was just 6 degrees. And what if the closing action was also 6 degrees. That is a total of 12 degrees used up in the lashing procedure, and so;
288 less 12 =276*NET duration after lashing.
Ok so;
I'm making this stuff up as I go, so I have zero ideas about this cam. But you can see how a person might get caught up in the specs, and build a disappointing STREET combo. This is VERY easy to do with a small engine like a 273, and especially so with a long-period cam..
Additionally; if you are looking to build a performance street car with a 273, then, I highly recommend a solid-lifter mechanical cam ........................... just probably not this one .................. unless perchance you can get more pertinent, and useful information about it.
Furthermore
with such a small engine, the elevation at which it will be operating in, becomes very important, because, as the engine travels ever higher, the cylinder pressure drops ever lower. If you are starting with a modest cylinder pressure, it doesn't take much change in elevation before the powerloss becomes very noticeable. The change is about 1/2psi per 100 ft.
For example;
a true 10:1 273, at sealevel with 165psi cranking cylinder pressure, at 2500, the pressure is predicted to have dropped to 153. And by 5000 the pressure is perhaps just 140. This is with no changes made.
With modest starting pressure of 145, by 5000 the pressure could be as low as 120, which IMO, is for lawnmowers, lol.
As the engine goes up, the air is less dense, and so the carb will go ever richer, and that is a double whammy for her, loosing even more power.
I'm just trying to be helpful, as I noticed your location.
