Thoughts on future build?

[schaferstephen]

I'm definitely not going to put any money in the stock head, it's just not worth it.

Let me ask this.. I'm considering using 1.6 roller rockers. In that case, would I want to go with less duration? I just spoke with some folks at comp cams, and they recommended going with a 108 lobe. I think that's a bit low, but I wouldn't mind a 110 for lope and faster rev, but.. I don't want to sacrifice too much bottom end.

Also, what type of pistons should I be looking at? Is there any need for forged, or is that overkill? Also, dished or flattop?

 

[170-3tree]

I think it has been pretty well proven to me that comp isn't a good source for help choosing a cam. I like using vizard's theory. Someone cab turn up a link to his cam selection article. Basically he uses an equation to determine lobe centers based on volume per cylinder versus the size of the intake valve. It gives a general rule to follow, while other sources that go more in depth will modify his equation to some extent based on flow characteristics and valve angles.

Basically using the equation on a 200 with the 1.84" intake valves that come standard on the aluminum yields 112* lobe centers. I believe 1.75 from the log head gives 110 but really factoring in the flow of the head 108-109 since it flows so low and the chambers aren't the best for ignition.

As far as pistons goes, that will depend solely on how you want to use it. If you will always be pushing redline, I'd go forced. But otherwise I believe cast will be fine. And dished versus flat will will be solely based on how you choose to get compression up. The 280-112* cam will probably like somethin in the 9.7-10.0 range depending on what she'll be drinking for fuel.
Essentially 1.6 rockers will just add lift, and even better, average lift to the cam. It will ad to the sound of the car a bit. But it should not influence the duration or lobe centers at all.

 

[schaferstephen]

Hmm interesting. So it looks like you have a setup similar to what I'm considering - how does your cam/head combo work for you? You're pretty happy with it?

I guess what i'm hearing overall is stick with a 112 lobe, and go for long duration such as 274/274 or 280/280.

If I do order a port and polish job with the head, will that have a noticeable negative effect on low end?

 

[170-3tree]

I have only driven her once. Untuned. And God I loved it I can't wait to get the last kinks worked out and broken in. I got the arvinode exhaust which was some doing to get worked out totally but it sounds really really nice. Mild lope in the idle and when you get on it it sounds like a force to be reconed with. And it feels like it is too.

If the job is done well just cleaning things up and smoothing it out porting will have a very minor affect on low end. But will help out a bit mid to high. I can't say whether or not its worth it though. I'd wanna see some hard before and after dyno graphs. Not just numbers.

If you want a little assurance look at the dyno graphs on classic inlines specifically the ones comparing large logs to the aluminium and mraley's 2bbl comparisons. My biggest draw is the near square torque curve. Takin a few points off low end may not be as big a deal as it is on a stock engine.

I'm hoping that if I'm off on anything so far someone would chime in, but I'm drawing off my own experiences as well as many things posted on the forum in the hardcore section and this section.

Gerald.

 

[schaferstephen]

Thanks for all the input guys. I guess right now, I'm deciding if I want to try a Paxton super charger like here:

viewtopic.php?t=19007&highlight=mustangaroo

Or if I wanna go naturally aspirated. I'll compare some costs and numbers that I can find, and go from there! Either way... I'm DEFINITELY in for a treat in the fall

Thanks again for all the help yall!

 

[170-3tree]

When ordering parts, remember that the head may take a few months to get made and whatnot. They are in relatively high demand and take a lot to make. So just remember to order accordingly.