Mike can you look at the cam quest specs that I printed out? I'm not sure if i specified the right info my my engine. If I did then they are saying my peak HP would be 414 with this cam. Hard to believe. These were the items that I'm not sure if my selection is accurate.
intake / exhaust valve: 2.19 / 1.71
compression: 10.5 (not 10.7 selection)
induction airflow: 600 CFM (This is my edelbrock carb CFM)
intake manifold: domestic dual-plane std-flow (wasnt sure what my stock 351 intake manifold is)
When that pdf document opens the page is black with nothing else on it. What cam is it?
I see the valve size you have for your cylinder head is incorrect. The stock cylinder head valve sizes are 1.84" intake and 1.54" exhaust.
You're right, hard to believe. With stock cylinder head port configurations and stock valve sizes it won't get to that HP rating. A stock intake and the carb size will prevent it as well.
Post the cam part number and I will take a look at it.
I added the attachment again but I'll post the spec that I added in case you can't read it. I wasn't too sure I added the correct info. For example, they ask for induction airflow in CFM and so I used my carb which is 600 CFM. They also ask for what type of intake manifold and the only choices are dual plane or single plane and so I chose dual plane standard which is what i think the stock 4v is. They also ask about headers and i selected large-tube headers, mufflers without cat which i think my hooker super comps long tube are with the exhaust pipe at 2 1/4.
BTW I changed the valve sizes to what you gave me and now the HP is 358HP @ 5000 and 423 Torque @ 3500 which is more believable.
The file won't open but from the name I am guessing it's the Magnum 270 cam. Those results are more believable. It might be 5 or 10 hp on the high side. But I don't think you'll get much more from only a cam swap.
You have to purchase something like Desktop Dyno to get more accurate results. I had a copy of it many years ago. It doesn't work on Windows 7 or newer. Anyway, it requires much more input. For example it has many different single and dual plane intake manifold selections, and requests more specific cylinder head information.
The stock intake is a dual plane so the selection you made is the best option offered. Camquest's calculations might be base on a something like an Edelbrock Performer RPM intake which is a popular dual plane.
Did you try any different carb CFM numbers, maybe 650 or 700, and intake manifold type to see if the results increase?
Yeah, it can get hard to select one. Of the Comp cams you're looking at. The Hi Energy 268H or the Magnum 270H still seem to be the top contenders.
The XE256 makes a more bottom end power by creating more cylinder pressure at low RPM's. With 10.7:1 compression ratio detonation (knocking, pinging) is more likely. I think that's why a couple of Comp's tech people mentioned to me the Xtreme series (XE) were more suited for 9:1 compression ratio motors.
If you are concerned the Magnum 270H might make it idle too rough then the Hi Energy 268 would seem more suitable.
The horsepower numbers of those cams are probably on the high side. But they are still useful for comparison.
Best of luck. Let us know what you end up with. I ended up trying a couple before settling on what is currently installed, Ford Racing's X303 hydraulic roller (I think its made by Crane). In the process I learned quite a bit.
Whatever you select, don't forget, many of todays oils do not have enough of that zinc phosphate, I think that's what it is, needed to protect the lobes on flat tappet type cams. I believe something like Valvoline's Racing Oils are okay. I'm sure there are others as well. Otherwise there is higher risk of a lifter damaging a cam lobe. Comp, and some others also offer break-in oil to further protect the cam during that critical break-in period.
What software are you using to generate those hp numbers? They are good for comparison but all seem a little high. It usually takes different cylinder heads or a lot of work to the stock cylinder heads for small block Fords to perform like that.
Funny I just spoke to the lunati guy and he said the same thing on the flat tappet heads and wear. I'm now thinking to go hydraulic roller now after talking with the guy. Currently I use valvoline and additive so i dont wear it. He recommended these customer heads:
Grind number 035-1014-1019-112+4 would be 221/230 @ 050, .485”/.485” lift on 112LS. Excellent hydraulic flat tappet that sounds good, runs good and is easier on parts so more reliable than most designs on the market.
Mike do you know what the specs are for the stock cam? I found some specs but could not find duration @ 50.
Is that grind number, 035-1014-1019-112+4, a Lunati or a Comp cam? Yes, it's true, cam series like Comp's Xtreme, and Lunati's Voodoo are harder on valvetrain parts and sometimes create small amounts of valvetrain noise. The ramps on the cam lobes are designed with higher acceleration rates to open the valve quicker and hold it fully open for a longer duration then close it quicker. Personally, I prefer something a little easier on the valvetrain. I'll give up a few horsepower for some added reliability.
Isky cams has a tech article about inverse radius cams. I believe the Xtreme series and Voodoo series are in this category. Here is a link. Select the article about Inverse Radius Cams. An article about Longer Exhaust Duration is also interesting. http://www.iskycams.com/tech-tips-2000.html
I guess your learning there is more to these than picking something from a catalog by its description.
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