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Discussion Starter #1
i'm looking to change cams, i have a 302 , 30 over, flat top pistons,289 small combustion heads, headers, 720 carb, performer intake. 2 1/2 exhaust, automatic, 2500 stall!! Any suggestions on a good street strip cam? Some thing that will idle ok.I went to big before and didn't want to make the same mistake! in it now duration 288 intake 292 exhaust lift 590. 110 degree. will not idle in gear! not enough stall.
 

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Lemonshindig is right. That cam is hardly too much for the street, but the car is a little overkill. You'd be better of with a 650 vac secondary. And recheck your timing...?

.590 lift?!? Really?
 

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I'm currently running a Comp XE262H which is a pretty mild cam good for about 1500-5500 rpm. I bumped it a little with some Crane 1.7 roller rockers. Cam provides really good power and you can tell it is in there as it has a slight lope.
I would also step back on the carb to a 600 or 650.
Tom
 

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Discussion Starter #8
I did have a 650 Holley and it was not enough! changed jets and was not alot better with the biggest jets !! What i'm having an issue with is either lob seperation or lift or some thing!!! It does idle but i'm pushing off my torque converter!! And yes the 720 is jetted down a bit!!Its when i changed my cam ,thats when i started having the idle issue!
 

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What rear gears? You need at least 3.50 gears with any upgraded cam on a 289 IMO.

The idling problem is not related to the stall speed at all. You have too much cam and/or carb and the butterflies are open too much and the carb is off the idle circuit. You can sometimes solve this problem with more initial timing.

I have a 230/236 @ .050 with 109 LSA and .570 lift in my 347 with worked heads and a 750 carb. It idles with a little lope at 750, pulls 5th gear at 1500 rpm and revs to 6500. On a 289 this would be way too much cam. I would shoot for something in the 220/225 range with 109/110 LSA.

LSA has a lot to do with how a cam idles.
 

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Depends on the driving you do. I switched from a 3.50 to a 3.00, since most of my driving then was on open roads and highways. This was with a wide-ratio 4-speed. Haven't decided if I'll switch back at some point, now that it's no longer a 'driver'.
 

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With stock heads, I would not go anything bigger than a Comp Cams xtreme energy XE256h camshaft or something of similar spec. Honestly, with the heads and intake you have you will see minimal gains with a cam swap. Should make it sound a little better. If you go anything much bigger than this camshaft you wont make any gains and you will just hurt driveability.
 

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I have a 302 in the wifes Mustang II with automatic and stock converter. I used the Comp cams 268H nice lope and runs good from 1500 to 5600 idles at 750 600 in gear but works great with the auto and still has vacume for brakes heater controls and shifting.
 

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Discussion Starter #14
I have 355 rear gears!The heads are worked!I do agree i have too much cam! i was putting a 5 speed but money got tight, so the auto went in. I set the car up for the stick! That is why i asked to see what everyone else was running for a cam! I was looking for smaller!
 

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Discussion Starter #15
What rear gears? You need at least 3.50 gears with any upgraded cam on a 289 IMO.

The idling problem is not related to the stall speed at all. You have too much cam and/or carb and the butterflies are open too much and the carb is off the idle circuit. You can sometimes solve this problem with more initial timing.

I have a 230/236 @ .050 with 109 LSA and .570 lift in my 347 with worked heads and a 750 carb. It idles with a little lope at 750, pulls 5th gear at 1500 rpm and revs to 6500. On a 289 this would be way too much cam. I would shoot for something in the 220/225 range with 109/110 LSA.

LSA has a lot to do with how a cam idles.
LSA? is that the lobe over lap? if that is 109 is alot more than what i put in! I do have a 302 ,i have a lope which pushes the car at a light! which i fine. Thats why i'm droping to a smaller cam, i was looking at comp! .450 lift, 255/260 @ .050 with lobe sep @ 112 1500 to 6500, like i was saying with only a 2500 stall is my concern, i should just put a manual in it..lol
 

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i'm looking to change cams, i have a 302 , 30 over, flat top pistons,289 small combustion heads, headers, 720 carb, performer intake. 2 1/2 exhaust, automatic, 2500 stall!! Any suggestions on a good street strip cam? Some thing that will idle ok.I went to big before and didn't want to make the same mistake! in it now duration 288 intake 292 exhaust lift 590. 110 degree. will not idle in gear! not enough stall.
Hi Bud,
I'm curious, why you state "not enough stall". Also, What intake are you running? What is the idle vac reading? What is idle in park?
 

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450 lift, 255/260 @ .050 with lobe sep @ 112 1500 to 6500
That is way too much cam for what you are running. You also most likely do not have anywhere close to the amount of static compression you need to run a cam that large. With that much overlap you are bleeding off a bunch of cylinder pressure and that is part of the reason why the engine is not running well.
 

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A Performer type split duration (204/214, I think, with .472 lift) works well. I have the Summit version and installed it straight up. I, too think you have a little too much carb unless you run high rpm all the time. A 600 would do well. I'm very happy with the Edelbrock 600 cfm manual choke.
 

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LSA? is that the lobe over lap? if that is 109 is alot more than what i put in! I do have a 302 ,i have a lope which pushes the car at a light! which i fine. Thats why i'm droping to a smaller cam, i was looking at comp! .450 lift, 255/260 @ .050 with lobe sep @ 112 1500 to 6500, like i was saying with only a 2500 stall is my concern, i should just put a manual in it..lol
LSA is Lobe Separation Angle...and contrary to popular belief, it has nothing (directly) to do with how a motor/cam idles. How it indirectly affects idle is through overlap, as you mentioned. I don't have my calculator handy (posting from my phone), but 255/[email protected] and great valve lift, with a 112LSA and stock type heads would probably make decent power, depending on your compression. Yes you'll sacrifice idle vacuum, yes you'll have to adjust the carb properly. My gut tells me the issue isn't the cam...even still. I might have chosen another cam myself...but it is what it is and as I said I don't think it's the problem. And the problem most CERTAINLY isn't the 2500 stall convertor lol.

First, baseline the carb! If you don't know how to do it properly, buy a video, book, or pay someone to do it. A Holley carb MUST be baselined properly prior to tuning it when troubleshooting. Period.

Second, check for vacuum leaks. Seriously.

Third, you never mentioned timing. I run my motors either locked out with FULL advance, or...depending on the distributor, adjusted to about 24* at idle, and all in before 2000rpm. My last 347 was 11:1+ compression and started just fine with a late model mini starter. The benifits include sick throttle response, great off idle power, and far fewer tuning issues. The only drawback was the light weight starter.

Oh wait...that's not a drawback either =D.

Anyhow, hope that helps a little!

Cris

Oh! One other thing! The only time a 700cfm+ carb is too big for a 289/302 is if the person can't tune it. Small carbs are tuning crutches because they increase the signal. If tuning a Holley is an issue, buy a 1407 Edelbrock. It'll outrun any Holley under 700cfm, and is dummy proof. I actually prefer them on street only cars.

C
 

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Discussion Starter #20
I have messed with carbs, Used a 600 650 and my 720!I can and have not had any issues tuning a carb, i did have some one double check me and still could not get in in check! Thanks all for the advise! I have a few ideas for cams that other's are using.I will let you guys know how i made out!Winter still in N.H. So i won't have it out for another month!
 
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