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Old 04-01-2008, 11:28 AM   #1
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XR258hr-12 a good all around cam???

I have a 305 TPI, stalled 700r, headers, full exhaust, and a little nitrous. I am soon to have a 3.42 gear, 22 lb injectors, and afpr. I have been looking for a cam and I have came up with a XR258 as a good cantidate. I am keeping stock heads so with this cam I should have no problems right? What do you guys think about this cam for my mods? The car probably wont get any other mods to the 305, so would this cam be supported by my few mods? Also getting aluminum roller rockers 1.5 ratio and replacing springs and retainers when the cam goes in. It shouldnt be too hard to tune with a 112 lsa should it?
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Old 04-01-2008, 11:51 AM   #2
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Re: XR258hr-12 a good all around cam???

I am running the same cam in my 305 TPI. I had the cam professionally installed into my engine when it was freshly rebuilt. The cam makes a great deal of low end torque, and pulls nicely up high. I have not had any tunning issues with the cam, other than a few bad vacuum hoses and electrical wires that have been causing intermittent problems, but none are related to the cam.
I don't know of anything that was special that needed to be done to the heads in order to take this cam. I am running the stock heads that were freshly rebuilt with new springs to support the new cam.
Power comes in by 2K RPM. The car pulls nice and hard, and the great thing is that you don't have to drive the car hard to get this kind of performance.
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Old 04-01-2008, 12:24 PM   #3
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Re: XR258hr-12 a good all around cam???

That cam has .510/.510 lift, stock heads are not set up to support that much lift.
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Old 04-01-2008, 12:28 PM   #4
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Re: XR258hr-12 a good all around cam???

I am just worried about that cam being too small to bother swapping, but I am limited by the stock heads. Anybody seen any significant e.t. drops, or horsepower gains from swapping the peanut cam for the XR258???
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That cam has .510/.510 lift, stock heads are not set up to support that much lift.
You are mistaken, it has .480/.488 lift. You looked at the one for big blocks.

Here is the link to the specs.
http://store.summitracing.com/partde...8&autoview=sku

Last edited by WhiteIrocZ; 04-01-2008 at 12:30 PM. Reason: Automerged Doublepost
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Old 04-01-2008, 12:44 PM   #5
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Re: XR258hr-12 a good all around cam???

Quote:
Originally Posted by WhiteIrocZ View Post
IYou are mistaken, it has .480/.488 lift. You looked at the one for big blocks.
My bad....

If you have the peanut cam, you are going to LOVE a new cam! If it were me I'd go with a little more duration.

I have this cam. A touch more lift would be nice. I wouldn't go with any more duration than this.
http://store.summitracing.com/partde...4&autoview=sku

Last edited by mnorton; 04-01-2008 at 12:52 PM.
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Old 04-01-2008, 01:22 PM   #6
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Re: XR258hr-12 a good all around cam???

Quote:
Originally Posted by WhiteIrocZ View Post
I am just worried about that cam being too small to bother swapping, but I am limited by the stock heads. Anybody seen any significant e.t. drops, or horsepower gains from swapping the peanut cam for the XR258???
----------

You are mistaken, it has .480/.488 lift. You looked at the one for big blocks.

Here is the link to the specs.
http://store.summitracing.com/partde...8&autoview=sku
.488 lift is way to close, imo. i would definately have the heads checked out and make sure you can go that high. On stockers, with no work, I dont think I would go much over .470, even if they could take it.
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Old 04-01-2008, 03:15 PM   #7
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Re: XR258hr-12 a good all around cam???

I swapped my stock LB9 cam, same as the L98 cam, for the xr258. I will have some dyno numbers as soon as the engine has been fully broken in. The guys that rebuilt it said that it would take about 5K miles.
So far my impressions are that at least torque wise, this can seems to make a good amount of torque more than stock in the low end. I am not sure as to hp, because I have been taking it easy on the engine.
I was considering the xr264hr-12, but had worries about how the stock speed density computer would like that, so I went with the slightly milder cam.
The person at comp cams that I spoke to, said that I should be able to see a 20 to 25 hp increase over stock with that cam. I guess in due time I will find out.
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Old 04-01-2008, 10:10 PM   #8
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Re: XR258hr-12 a good all around cam???

Quote:
Originally Posted by mnorton View Post
My bad....

If you have the peanut cam, you are going to LOVE a new cam! If it were me I'd go with a little more duration.

I have this cam. A touch more lift would be nice. I wouldn't go with any more duration than this.
http://store.summitracing.com/partde...4&autoview=sku
That looks like a damn good cam, actually just what I was looking for. It has good duration(not too much) and lower lift for the factory LB9 heads. This is probably the cam I will go with also. Any video's or sound clips of the car with this cam in it. What does everyone else think about this one?
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Old 04-02-2008, 01:53 AM   #9
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Re: XR258hr-12 a good all around cam???

Do not let those cam numbers fool you. This cam has very good ramps. It will feed a 383 (my DD). Spin wheels 1st, 2nd, and into 3rd with a 3.07 something like 300 hp and 400 tq
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Old 04-02-2008, 09:30 AM   #10
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Re: XR258hr-12 a good all around cam???

Quote:
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Do not let those cam numbers fool you. This cam has very good ramps. It will feed a 383 (my DD). Spin wheels 1st, 2nd, and into 3rd with a 3.07 something like 300 hp and 400 tq
Which cam are you speaking of??? I bet both of these are very mild in a 383.
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Old 04-03-2008, 02:08 AM   #11
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Re: XR258hr-12 a good all around cam???

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Originally Posted by WhiteIrocZ View Post
Which cam are you speaking of??? I bet both of these are very mild in a 383.
comp XR258HR-10

I guess I do not understand "mild cam"

Good cams make a lot of torque (cylinder pressure).

Some do it at low rpm and some at high rpm.
Others are high peak and others are wide and flat.

High rpm cams are high HP, they make the same or less torque at higher rpms.

The big debate is over which is "better"

All of the equipment has to match, (engine, all internals), drivetrain (tranny, gears, tires) and chassis (suspension, body).

Any mismatch is a big bunch of trouble.

Not everyone "races" or wants to fix broken parts.

What good is the perfect car with mild/peanut tires (all smoke). Or the Big bad motor and a broken windshield (mild/peanut car?).

There is lots of talk about mild cams, nobody talks about "peanut/mild cars".

Remember:

All extra power comes at a price.

The farther from stock you get the harder it is to tune.

"Fast, cheap, or reliable pick two"

Time, money, or knowledge, the less of one you have the more important the other two become.
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Old 04-03-2008, 08:31 AM   #12
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Re: XR258hr-12 a good all around cam???

I was actually referring to the sound of the cam. If your Vette was my DD, I would probably go with that cam also. I would get tired of the surging and stalling etc. of a big cam.
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Old 04-03-2008, 06:13 PM   #13
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Re: XR258hr-12 a good all around cam???

17 in of vacuum and a dead smooth idle, no lope.

It has 41 degrees of overlap at 110 lobe sep, the 112 will have 37 overlap.

They will start to lope at 50 overlap or so, more with 305, less 350 or 383

The 110 LSA is running lean at Idle but within range of the Blm's (158)

Comp Cam's Cam quest numbers came out at 375 hp and 500 tq, There was just a little variation (15 hp 20 tq) all the way up to the 280 cams.

Datamaster's dyno 325 hp and 410 Tq.

Car (drivetrain) built oem 1000-5000 rpm, Intake (TPI) 1000-5000 rpm, so I matched heads and cam to 1000-5000 rpm. Still have to tune but it will run on a stock chip.

This car will light the tires in 1st (just mash the gas) chirp 2nd (with a foot of side slip) and get loose going into third at 75 mph. This is at the limits of the car and it has a 51/49 weight balance. Add wet roads or snow and "more is not better".
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Old 04-14-2008, 11:49 PM   #14
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Re: XR258hr-12 a good all around cam???

Decided to go with an LT1 cam out of a 93 F body. It has good lift numbers .460/.470 and I got it for free. Toss in a set of 1.5 roller rockers and a good timing set with afpr and I'll get 300hp and probably around 425 ft. lbs. Sounded like a no brainer to me, so instead of a cam swap costing me $600-$700, it will be more like $300 with all gaskets, timing chain, AFPR, cam, and roller rockers, oil and coolant.
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Old 04-14-2008, 11:49 PM
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