cam upgrade

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440+6scamp

440+6scamp

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I built my motor close to factory specs thinking that would keep me satisfied for awhile. Well, awhile has come and gone already! I'm thinking about putting a bigger cam in it. This car is mostly street driven but will see a small amount of track time. Here's what I've got now:

440 6pack
9.5:1 comp
727 w/ 2200 stall
cam: hyd tappet, .454 lift, 218/218 @ .050
440 source 1.6 roller rockers (making lift .484?)
lightly ported 452 heads w/ headers
3.55 and 4.10 gears (I have both and switch back and forth)
3400 lbs total weight

I'm thinking about the .507/.510 240/246 comp cam. But w/ a rocker ratio of 1.6 the lift would be .541. Too much? Would I be better off w/ the .488/.491 230/236 (.521 lift w/ 1.6)? Is there another cam that would be better for my application? Should I go w/ a roller hyd instead of a flat tappet?

I want the car to idle decent but I also want to be able to scare my passengers!

Is a 2200 converter good enough for the cam I would put in? I'm willing to change it as well.

I'm sure this is one of the most discussed topics on here but I would appreciate any feedback.
 
I like the thought of a solid cam. I don't mind adjusting it and acctually enjoy that kind of maintenance. However, I struggle to get these valve covers to seal. So, I decided to stick w/ the hyd flat tappet. I got this one:

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=708&sb=2

230/236 duration w/ 488/491 lift. W/ my 1.6 rockers the lift is 520/523. Hopefully this will be a decent improvement. I was worried that I would need a higher stall converter w/ anything bigger then this. I might go that route in the future though.
 
That's a good one. I think you'll be happy with it.
 
440+6scamp said:
I like the thought of a solid cam. I don't mind adjusting it and acctually enjoy that kind of maintenance. However, I struggle to get these valve covers to seal. So, I decided to stick w/ the hyd flat tappet. I got this one:

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=708&sb=2

230/236 duration w/ 488/491 lift. W/ my 1.6 rockers the lift is 520/523. Hopefully this will be a decent improvement. I was worried that I would need a higher stall converter w/ anything bigger then this. I might go that route in the future though.
Click to expand...

I'm using that same grind on my 383 build.. let me know how you like it.
 
No power brakes. 926 comp springs. This cam calls for 911 springs but tech support told me I'll be fine w/ the 926's.

Will do Plik. I should have it swapped in 4 or 5 days.
 
I hate to disagree with Comps tech support, but I don't think you'll get the most from that cam with the worn 926s. It will run, but you run a greater risk of the cam being wiped and the rpm potential will be lowered. Even more so if you go with 1.6s. If it was me, I'd suggest something smaller like the XE268 if you want to stay with the heads as they are now. Just my $.02.
 
My springs aren't worn. I've only got 400 miles on the motor.

The 926's have a seat load of 109 @ 1.8" and a rate of 415 lbs/in.

The 911's have a seat load of 122 @ 1.9" and a rate of 373 lbs/in.

So from that I gather that the 911's are softer but must be a little taller since the seat load is great for a taller installed height. My stalled height is 1.88". So w/ the 926's at 1.88" my seat load is less then 109.

Given that info, what do you think? Am I ok w/ a stiffer spring but less seat load or would you rather see a higer seat load?
 
Do you know what the installed height of your springs are now? You need to look at the pressures ON YOUR ENGINE, rather than in any book to know for sure. I rana few numbers quickly here. For installed at 1.80, 1.85, and 1.9. I think stock should be 1.850 but I am going off an iffy memory. So using those heights you could be as far as 34lbs light at max lift and as low as 50lbs on the seat with 926s for the .510 lift cam. With faster rate cams, low pressures are not good. Think of it this way... If the cam survives break in and use the rpm potential will be lowered by at least 10% and because the negative affect is not linear, but a function of rpm, it could be much lower than that. The 911s are the recommended single spring option. They would be heavier on the seat intalled at 1.85 than the dual spring 925s, and would be heavier at max lift, but will not last as long. The reason there is a premium choice is because that is really what the cam needs to live well long term. Again, will it work? (shrugging)Maybe. I don't think it working as designed is any better odds than 50% with 926s. If it were me, I'd step up the springs to at least 911s. That requires no head work. 925s would require the spring seats and guides be machined.
 
Makes sense. My installed height is 1.88". So the 926's would have less then 109 lbs of seat load (listed at 109 at 1.8").

I'll play it safe and get the 911's.

Demon, I've got the Edelbrock 6 pack intake and new Holley carbs. Will a 3000-3200 converter run hot on the street? Any downsides to running it on the street?
 
3000 is no sweat. just use a decent cooler. I have a 9.5 Dynamic that flashes 4500 in one of my street cars. Been in there 8 years and driven a lot.
 
440+6scamp said:
Makes sense. My installed height is 1.88". So the 926's would have less then 109 lbs of seat load (listed at 109 at 1.8").

I'll play it safe and get the 911's.

Demon, I've got the Edelbrock 6 pack intake and new Holley carbs. Will a 3000-3200 converter run hot on the street? Any downsides to running it on the street?
Click to expand...

Run your complete build pass the guys at Dynamic or Ultimate for size and duty but I run 3400 stall in the Demon on a B block and driving around town you barely notice it. That all changes tho when you stomp it and yes to a good tranny cooler. I also always recommend a 2-3 quart larger aluminum tranny pan, gets you a little more cooling.
 
I run an Edge converter in all my vehicles. Andre really knows his stuff and he will make you a converter depending on your set up.
 
Yes, I have Ross pistons w/ valve relief. I'll put a solid lifter in and rotate the engine by hand to make sure I've got clearance. Since I'm changing the springs too I guess I can run the piston up and drop a valve down and measure exactly how much clearance I've got.
 
Dude, you'll have mile of valve clearance. Don't give it another thought. Stab that pup in and have fun.
 
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