| Re: My engine... |  | ||
| Re: Re: My engine... -- Arnie | Post Reply | Top of thread | Maverick Message Board |
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Posted by: Fred H ® 2001/10/11, 08:28:57 Author Profile |
:::Which ones?The Holley's are already 2.02/1.60,the World Products heads I'm looking at are supposed to be already ported as well.My tunnel port heads are gonna be left alone.I'll just have someone go through them,if I can find someone that knows anything about them and won't charge me an arm and a leg to do it.
:: ::I do not know much about the tunnel ports except they require a lot of rpm. I would use the either of the other heads. If compression is not a concern, I'd try to maintain at least 12:1 and put in a pretty snappy solid. Keeping in mind that you plan to run nitrous and the heads are adequately ported, I'd run a cam somewhere in the neighborhood of .600" lift mid-250@.050 intake duration and high-250 to low-260 @ .050 duration on the exhaust and keep the lobe centers around 110. If you run a stroker 302, I'd probably bump the duration up 6-8 degrees (take advantage of the bigger lungs) and widen the lobe centers to about 112. :: ::You can run nitrous on 12:1 with no problem. You would have to run race fuel to curb detonation. The motor cannot detonate on nitrous. On the street you could get away with at worst 50/50 mix of pump gas/race gas and could get away with a 70/30 ratio. :: ::Just my opinion as I have been through this a few times. : :I am using the tunnel ports as I stated above for another project,and I'll more than likely "clay" the engine for piston to valve clearence.That's really the only surefire way to tell if a cam will work or not.Unless you know of another way?I know there's a tool you can measure the lift at the spring with, but heard it's not very accurate.What are your thoughts, and thanks for the helpfull info. I prefer to clay the piston as well. Rotate the through a couple of times and then measure the cross section of the thinnest area. I like the clay because it gives you a "picture" of what is going on and there is no doubt that the clearance is fine. A couple of tips to claying. One, install a couple of head bolts to prevent the heads from falling of the motor. Tighten the bolts until they are about a 1/4" from seating against the head. This will allow the the head to lift of the deck if there is insufficient clearnce and will prevent possible bending valves. Two, use light springs to test cleaance. You want to "feel" the valves hitting so you do not force anything. Three, assuming the piston is at or below deck height, check without the head gaskets in place. It saves wear and tear on the gaskets and you have an extra margin of safety with the gaskets installed. You will hear all sorts of stories as to how much clearnce you need. I prefer to maintain .100" on both valves if at all possible. Good luck with it. I enjoy giving out advice. I am sure there are others on this board who know much more than I but everything I am telling you has worked for me. P.S. If possible go for the stroker. |
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