Started with the specs for a stock 200, 1.75/1.38 valves, 1bbl, single exhaust, stock exhaust manifold, 9:1 CR, stock cam. It gives 105hp @4000 and 172 lb ft @ 2000. Pretty close to actual stock spec.
Then I start adding mods like some of you guys might.
2bbl Holley/Weber, no other changes, 116 hp @ 4000, 174 lb ft @ 2000. Not earth shattering, but better. A YF would give similar results.
Go back to the stock 1bbl back on, install headers, dual exhaust. 113 hp @ 4000, 177 lb ft @ 2000. Well, looks like headers alone are not the answer.
Add the 2bbl and headers. 124 hp @ 4000, 182 lb ft @ 2500 Now we're getting somewhere. That's a big enough difference to feel, but it comes in so low it will not be very lively.
We'll add a 260 degree cam to the above combo. 130 hp @ 4500, 183 lb ft @ 3000. Well that was disappointing. The head will not support the cam.
We need to do some porting. Same combo, but we'll open the exhaust and intake ports, improve flow by 10%. 153 hp @ 5500, 183 @ 3000. The head needs a lot of work!
Let's add a little more carb; 350 Holley. 159 hp @ 5500, 185 @ 3000
Hmm, need more carb.
Let's use a 500 holley 2bbl. 167 @ 5500, 186 @ 3000. same torque peak, but a much steeper slope off idle. The 350 is probably a better driver.
How about just bolting an unported 2V head, headers, duals and a Holley 350 to a stock engine? 160@ 4500, 193@3500 This really looks like a winner, even with just a stock cam.
Add a 260 cam to the above. 175hp@5500, 191 lb ft @ 4500
So, what did we learn?
1. No single bolt on does much.
2. Porting is essential on the log
3. headers alone do not make much difference
4. The 2bbl carb is only worth a few hp
5. The cam is not worth much by itself.
6. The 2V head is a good upgrade, even by itself.
Pretty much what we've known all along. The log is a dog. Pocket porting and opening the intake and exhaust ports pay big dividends. And all the bolt on go-fast stuff in Mike's catalog won't do much without a little more work to make the head breath better.
The 2V is a good option, if you can get one.
EA 3.0 is pretty good, but these are just simulations. They seem to run true with real world observations, but any two of you could assemble identical engines and get differetn results just because of skill and tuning ability.
Anyway, just a light diversion to think about the possibilities.
Then I start adding mods like some of you guys might.
2bbl Holley/Weber, no other changes, 116 hp @ 4000, 174 lb ft @ 2000. Not earth shattering, but better. A YF would give similar results.
Go back to the stock 1bbl back on, install headers, dual exhaust. 113 hp @ 4000, 177 lb ft @ 2000. Well, looks like headers alone are not the answer.
Add the 2bbl and headers. 124 hp @ 4000, 182 lb ft @ 2500 Now we're getting somewhere. That's a big enough difference to feel, but it comes in so low it will not be very lively.
We'll add a 260 degree cam to the above combo. 130 hp @ 4500, 183 lb ft @ 3000. Well that was disappointing. The head will not support the cam.
We need to do some porting. Same combo, but we'll open the exhaust and intake ports, improve flow by 10%. 153 hp @ 5500, 183 @ 3000. The head needs a lot of work!
Let's add a little more carb; 350 Holley. 159 hp @ 5500, 185 @ 3000
Hmm, need more carb.
Let's use a 500 holley 2bbl. 167 @ 5500, 186 @ 3000. same torque peak, but a much steeper slope off idle. The 350 is probably a better driver.
How about just bolting an unported 2V head, headers, duals and a Holley 350 to a stock engine? 160@ 4500, 193@3500 This really looks like a winner, even with just a stock cam.
Add a 260 cam to the above. 175hp@5500, 191 lb ft @ 4500
So, what did we learn?
1. No single bolt on does much.
2. Porting is essential on the log
3. headers alone do not make much difference
4. The 2bbl carb is only worth a few hp
5. The cam is not worth much by itself.
6. The 2V head is a good upgrade, even by itself.
Pretty much what we've known all along. The log is a dog. Pocket porting and opening the intake and exhaust ports pay big dividends. And all the bolt on go-fast stuff in Mike's catalog won't do much without a little more work to make the head breath better.
The 2V is a good option, if you can get one.
EA 3.0 is pretty good, but these are just simulations. They seem to run true with real world observations, but any two of you could assemble identical engines and get differetn results just because of skill and tuning ability.
Anyway, just a light diversion to think about the possibilities.
