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Discussion Starter #1
I am thinking about changing cams in my strictly strip cleveland and was wanting a few opinions on which would work best. I already have 3 cams, 2 of which are new, plus the one I was running at the end of last year. The reason I am thinking about switching(besides the never ending quest for more HP), is I am serioulsy considering putting a powerglide in my car and want to fatten the torque band up just a bit. The motor is .030 over, stock rods, stock stroke, 12-1 compression, ported 4v heads, Holley strip dominator intake, 1 7/8" primary 3.5" collector hooker headers, 920 cfm alchy carb.
The cam I was running at the end of last year that ran 9.97 @ 133 mph was a Crower solid (as are the other 2 I have) with 266 int, 277 exh @ .050, 103 centerline, 107 lsa, .628/.625 lift installed straight up.

The cam I am thinking about using is also a solid Crower, 270 int, 282 exh @ .050, 104 center, 108 lsa, .644/.654 lift and was thinking about installing it 4 degrees advanced.

The other I have that I feel is too small, is a solid Crower, 262 int, 265 exh @ .050, 108 center, 112 lsa, .640/.647 lift.

I currently shift at 7500 with my c4, using a 6400 convertor. Was figuring my 'glide convertor would still be around 62-6400, and would still like to shift it around 7400 or so.

Since the motor is all apart all I would need to buy would be lifters to change cams. Should I change it, or just leave it alone?

Thanks (sorry it got so long winded)

_________________
2000 Pro ET track champion
2001 Mod ET r-up
'69 mustang fastback, 351c, [email protected] mph
'70 mustang fastback, currently flintstone power
'93 Lightning

<font size=-1>[ This Message was edited by: kid vishus on 2/28/02 12:41am ]</font>
 

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On 2002-02-27 12:40, kid vishus wrote:
I am thinking about changing cams in my strictly strip cleveland The reason I am thinking about switching is I am serioulsy considering putting a powerglide in my car. The motor is 12-1 compression, ported 4v heads,
The cam I was running at the end of last year that ran 9.97 @ 133 mph was a Crower solid with 266 int, 277 exh @ .050, 103 centerline, 107 lsa, .628/.625 lift installed straight up.

The cam I am thinking about using is also a solid Crower, 270 int, 282 exh @ .050, 104 center, 108 lsa, .644/.654 lift and was thinking about installing it 4 degrees advanced.

The other I have that I feel is too small, is a solid Crower, 262 int, 265 exh @ .050, 108 center, 112 lsa, .640/.647 lift.
I'm sure you would like to consistently run in the 9's... which would probably be easier with the C4. BUT, that's not MY decision. I guess a taller first gear makes for a more consistent launch, and only one gear change instead of two is good for consistency as well. Oh well, I'll go ahead and say it anyway... TRAITOR!


On to the engine...

I believe you are currently using open chamber heads... An alcohol engine screams COMPRESSION. Those huge cams with a relatively low 12:1 compression ratio are going to be hard on the midrange... Upping the compression will help the midrange (and the launch using a glide') immensely. I'd strongly consider using a set of closed chamber heads (that have had the valves completely unshrouded) on your alcohol cleveland. This would give the engine the compression it needs to make full use of those huge cams with that intoxicating fuel.

The 270/282 cam is already ground 4 degrees advanced. I would NOT install it 4 MORE degrees advanced.

The smaller cams will probably launch best. I'm concerned you don't have enough compression to make the 270/282 cam work right. It might be a bit lazy taking off, especially with a glide.

Give the engine some more compression to unlock its potential, and you'll really be moving down the track... to the tune of consistent 9 second runs. (if you use a C4)


Just be SURE to do a GOOD job of unshrouding the valves on those closed chamber heads!

Good Luck!
 

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Discussion Starter #6
I had a motor with alot more compression than the motor I ran last year (13.85-1 vs. 11.5-1), a solid roller with comparable numbers to the solid flat tappet cam, and it didnt run any better at all ( best et 6.27 @ 108 mph vs. 6.29 @ 108 mph). So I'm not real sure if alot more compression is much help unless you can get to around 15-1. The new pistons I'm going to use are going to put it at 12-1 this year.

The convertor I have for the glide stalls about 5500 right now, I need to send it in and get it "loosened up" toget the stall where I need it so the car will leave halfway decent. I figure if the car with the powerglide will run 10.20-.30 consistently I willbe happy. I want to change classes and run the "box" exclusively and I need the car to calm down a little off the line to get my consistency a little tighter. Went down south over the holidays and ran some big dollar box bracket races, and got whupped. If you werent .50? something and dead on with a ?...you were toast. I could get the .50? part down, but my car leaves so hard, and having to shift twice, put me at a definate dis-advantage. (I know, run footbrake stuff. Unfortunatley there's alot more money to win in the box classes).
 

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Since we're on the awesome subject of cleveland cams i figured i'd ask for some great advice as well!! i race hobby stocks on a 3/8 high banked dirt oval. I have a pure stock '70 cleveland and I run from 5000-5600 rpm's with a 3400# car and 5.43 gears with a c-4 tranny. the rules state that we are to run 2v everything.
what does everyone recommend to use?? im kinda new to everything so bear with me. Thanks for the help!!

<font size=-1>[ This Message was edited by: jade17h on 2/28/02 8:43am ]</font>
 

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MC, I'd call Lunati and get their recommendation. At least get their part number and study the specs. Be sure to install the valve springs at the correct installed height for the pressure to be right.

Mr. Vishus, Open chambered heads definitelyh flow better... compared to stock quench heads. There's a LOT to be gained from unshrouding and properly clearancing piston domes. BUT, you're running 9's, so who am I to nit-pick. Your car flat out rocks!


Do whatever works for ya'


Good Luck!
 

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Jade,

Aussie heads with plenty of valve unshrouding done in the chambers, as much compression as you can get away with, a single pattern cam with a very tight lobe seperation, and a good set of 4 into 1 headers to produce good scavenging. As for cam duration, don't go too high. The engine isn't going to be able to make power much over 5500 rpm with a factory 2bbl carb, so don't cam it to run 7000.

You might ask around to see what people are having success with... but I'd -guess- a solid lifter cam around 235-240 degress @ 0.050" with around a 102-104 lobe seperation would be about right. The slower the corners, the lower the engine will get pulled down, and the smaller the cam will have to be.

Good Luck!
 

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Discussion Starter #10
On 2002-02-27 20:44, n2omike wrote:
Mr. Vishus, Open chambered heads definitelyh flow better... compared to stock quench heads. There's a LOT to be gained from unshrouding and properly clearancing piston domes.
Well, both motors were with open chambered heads. So maybe the higher compression motor had such a bad flame travel in the chamber that is why it didnt run any better than it did.

I have a set of closed chamber heads, they need valves and one chamber cleaned up from where it was fixed. But I'm trying to do this cheaply and was wondering if maybe one of the other cams I had would work better.
 
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