Oh wow, my E-mail didn't receive an update; I see this thread seems to be hanging.
Ok, I'll jump in,from post 12
The XE 262 has specs of 262/270/110/+4,with .050s of 218/224.Lifts are .462/.469
Your roller is .................262/270/110/+2,with .050s of 209/217 and lifts of .496.
Ok the XE has typical hi-performance ramps of 262 less 218=44*
Your roller has ramps of 262 less 209= 53*. That is 53 less 44=9 degrees more ramp. And they stole those 9+ degrees from the where it counts; the .050s. This makes your roller idle the same as the XE, but it is more than 1 cam size smaller (1 cam size is about 7*),when comparing the .050s. That means if the rest of the lobes are comparable, then the roller will power-peak about 200 rpm sooner, and typically 15 horsepower down. Please note; I said if the rest of the roller lobe compares to the FTH. Often rollers start off gentle like yours, then accelerate faster than the FTH, and dwell longer over the nose. This reduces peak horsepower, but broadens the powerband for more average power. This usually helps an automatic equipped car which has a .59 shift-split on the 1-2. Meaning the Rs will drop to .59 of the shift-rpm at the shift.
Take a look at the power curve of the XE that you provided. Don't look at the absolute number, but try to imagine where the power-peak is. I estimate at 5300. Then notice how rapidly the power falls off after that, and compare that to how quickly the combo builds power below that. Now, for low-ET,with an automatic you will need to shift well after the power peak to come in at a similar power level. This will keep the car accelerating smoothly. THe graph only goes to 5700, so lets work it out shifting at 5700. 5700 x .59=3363. So compare the outgoing power at 5700 (I estimate 340) to the incoming power at 3363 (I estimate 255). So you can see that there is a 85 horsepower drop during the shift. This will cause the car to momentarily slow down as the engine struggles back from the basement. A 4 speed has a 1-2 split of .718, so it will drop to 4093rpm, and the power there look like about 325, and so the power drop with it is just 15hp, hardly noticeable. This is why automatic cars need different cams than 4 speeds.
Ok so what should the shift-rpm be. Well we would have to extrapolate the top of the power curve out a fair ways. I'll guess 6000 and I'll guess the power there, to be 310. Ok now .59 x 6000 = 3540, and the power there I estimate at 275. So now we're down just 35hp. So we need to rev a little higher yet. Let's try 6200. I'll call it 290outgoing and .59 of 6200 is 3660, and the power there looks to be 285, so close enough. So with the XE 262, the 1-2 shift wants to be 6200 with a standard ratio Torqueflite.
Ok now we have no power-curve for your roller, but you can see how this works.
Lets say your roller makes 15 hp less than the XE at peak of only 5100, remember your .050 is 9*less.
But lets say your roller ramps are faster than his, so that your power at 6200 is greater, and your power is greater at 3660 as well. Well it could work out that your roller makes the same average power is that XE. I'm not saying it will. I am saying a roller cam could. I just don't know about yours.
Now; you should made aware that there are some roller cams out there with very very fast lobes. I think I have seen 33* ramps on some. And I know I have seen 39* from advertised to .050. That's pretty fast for a streeter. A 262 with 39* ramps would have 223* left to make power with. This is fully 2 sizes larger than the one you have. Those two sizes make the power-peak climb up about 400 RPM higher, and All things being equal that will make at least 30 hp more.......on the peak. And now you're comparing roller to roller, so your car will definitely pick up trap speed. Same 262, faster ramp, more power.
But it may not be power your after. A 360 with a 209@.050makes a lot of torque. This would make an ideal tow-car,to run your boat up to the lake. And the 262 will idle with a bit of a lope. And it could be useful to bleed off a bit of too much compression. As well, in the right combo, it might burn 87E10 all day/every day.And best of all; it will rev willingly to 6000, it's new 1-2 shift-rpm.
A 209 will also make pretty good fuel mileage, and will easily accommodate rears down to 2.94, and might even be happy with a 2.76, for excellent mileage. If the take off seems a little sluggish, just put a little TC into it.
Here is snapshot of what your engine might feel like with that 262 cam; Keep an eye on the VPs
Static compression ratio of 8.8:1.
Effective stroke is 2.95 inches.
Your dynamic compression ratio is 7.43
:1 .
Your dynamic cranking pressure is
145.18 PSI.
V/P (Volume to Pressure Index) is 131...................................................131VP
Here is what a hot 360 looks like.
Static compression ratio of 10.9:1.(aluminum heads)
Effective stroke is 2.86 inches.
Your dynamic compression ratio is 8.91:1 .
Your dynamic cranking pressure is
183.76 PSI.
V/P (Volume to Pressure Index) is 161..................................................161VP
And a stock 360
Static compression ratio of 8.0:1.
Effective stroke is 3.02 inches.
Your dynamic compression ratio is 6.91:1 .
Your dynamic cranking pressure is
131.95 PSI.
V/P (Volume to Pressure Index) is 120...................................................120VP
Read about VP here
, V/P Index Calculation
As you can see, the added compression brought the cylinder pressure up from 120 to 145, Making your engine feel quite a bit more powerful from idle to about 3000rpm, than a stocker. Yet quite a bit behind a hot 360 with a 270 cam and lots of compression, closing in fast on the maximum that pumpgas will support.
And one more; a fast ramp 209@ .050 say with 39* ramps equals a 248 advertised. This will still make similar power as your current 209, but gone will be any sign of lope.
Static compression ratio of 8.8:1.
Effective stroke is 3.10 inches.
Your dynamic compression ratio is 7.75:1 .
Your dynamic cranking pressure is
153.41 PSI.
V/P (Volume to Pressure Index) is 146...................................................146VP
See what happened to the VP? It's up 11.5% from 131. That is very significant.It's actually very close to what that Hot 360 would run, if it had to go back to iron heads; namely 146.
Ok so what's the point?
Well, whats your plans?
For low-ET, I wouldn't use your roller.
For a hot streeter, I wouldn't use that roller.
For a hiway cruiser, no again.
For a DD cruizing to the A&W on Saturday night, with a very little lope in the idle, and in an engine you want to have last forever, and burn el-cheapo gas; YES, it's a winner at last.
