2.76 open to 3.55 Sure Grip...expectations too high?
The 1973 318s were advertised at 8.0 Scr, but generally. come in around 7.8 after a reman. The closed-chambers will bump that up, but I think 8.3 is about where yours might be. At 2700ft elevation, that's gonna hurt the bottom end power. The Wallace calculator predicts about 124 psi cranking cylinder pressure.
I had a freshened 1973 smogger , that I used to use as my winter engine, stock long-block, with a small-port intake, a 4bbl,fresh-air,and headers. I put that engine in every winter 5 or 6 years running, and it never had the same trans or gears in it. But when it had a a 904, then it also had a 2800TC. and when it had the 2800, then it usually had 3.23s. And in that combo, she was a ripper. and here's why; Below is a 5.2 Magnum graph, so much more powerful than either of our engines. But look at the shape of the curve. At 1800, it shows about 270 ftlbs. Let's arbitrarily drop that to 70% for your combo; so 189. And your TC is gonna multiply that by say 1.6 at Zero mph, so 302. Now the trans has a first gear multiplier of 2.45, so now 741. With the rear at 2.76, then 2045 into the rear axles.
But with 3.55s then 2630. Checkmark that.
Lets up the TC to 2800
On the graph, that looks like 295 ftlbs. Again at 70%=207ftlbs. But this time I'll estimate 1.7 in the TC@zero mph, and still 2.45 low and back to the 2.76s; I get 2374 ftlbs. So now with the TC alone, you are half way between 2.76 and 3.55, as compared to the 1700 stall. With 3.55s, this combos to 3054! and now 49% greater than where we started.
Ok but I know you're thinking, that don't sound like all that much,right? Well hang on; 189ftlbs at 1700rpm is 61hp. Whereas 207 at 2800 is 110hp, using the estimated numbers, this is an increase of 80% in horsepower.
Ok now I'm not saying the 2800TC will increase your delivered power to 110hp@2800. I'm saying you could be looking at a power increase of 80%@zero mph, over an 1800TC. And that is a really big deal. You understand the difference?
This is the bandaid for the low cylinder pressure.
The 1973 318s were advertised at 8.0 Scr, but generally. come in around 7.8 after a reman. The closed-chambers will bump that up, but I think 8.3 is about where yours might be. At 2700ft elevation, that's gonna hurt the bottom end power. The Wallace calculator predicts about 124 psi cranking cylinder pressure.
I had a freshened 1973 smogger , that I used to use as my winter engine, stock long-block, with a small-port intake, a 4bbl,fresh-air,and headers. I put that engine in every winter 5 or 6 years running, and it never had the same trans or gears in it. But when it had a a 904, then it also had a 2800TC. and when it had the 2800, then it usually had 3.23s. And in that combo, she was a ripper. and here's why; Below is a 5.2 Magnum graph, so much more powerful than either of our engines. But look at the shape of the curve. At 1800, it shows about 270 ftlbs. Let's arbitrarily drop that to 70% for your combo; so 189. And your TC is gonna multiply that by say 1.6 at Zero mph, so 302. Now the trans has a first gear multiplier of 2.45, so now 741. With the rear at 2.76, then 2045 into the rear axles.
But with 3.55s then 2630. Checkmark that.
Lets up the TC to 2800
On the graph, that looks like 295 ftlbs. Again at 70%=207ftlbs. But this time I'll estimate 1.7 in the TC@zero mph, and still 2.45 low and back to the 2.76s; I get 2374 ftlbs. So now with the TC alone, you are half way between 2.76 and 3.55, as compared to the 1700 stall. With 3.55s, this combos to 3054! and now 49% greater than where we started.
Ok but I know you're thinking, that don't sound like all that much,right? Well hang on; 189ftlbs at 1700rpm is 61hp. Whereas 207 at 2800 is 110hp, using the estimated numbers, this is an increase of 80% in horsepower.
Ok now I'm not saying the 2800TC will increase your delivered power to 110hp@2800. I'm saying you could be looking at a power increase of 80%@zero mph, over an 1800TC. And that is a really big deal. You understand the difference?
This is the bandaid for the low cylinder pressure.
