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Old 03-18-2008, 07:32 AM
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Xr288hr...?

Hey all, it's another cam question! First off, here is my setup:

- 383 4 bolt SBC
- All forged internals, flat top pistons (around 10.4-10.5 c/r)
- AFR 195cc Heads
- Super t10 4 speed

Going to be a mean street car, and I want to go as big as possible. My question is, am I limiting myself with this cam? Could I get away with more lift/duration on the street and not compromise the power brakes/steering (not like it matters)? What is the 'biggest' that I could go and still keep it street worthy? Also, with hydraulic roller cams, do you need the 'lifter followers' as to keep it from moving inside of the lifter bore? I would assume that you would need that for roller lifters. This is what I had in mind:

http://store.summitracing.com/partde...8&autoview=sku

Thoughts?

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Last edited by mrdreex; 03-18-2008 at 07:40 AM.
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Old 03-18-2008, 10:06 AM
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xr288hr

What gear ratio? What size carb? What is the max lift for your valve springs? Will you be using roller rockers? Aprox weight of car?

Bob
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Old 03-18-2008, 10:13 AM
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Yes you will need roller lifters, yes they will need to be captivated by the bar across both of them. the picture shown with the link you supplied shows flat tappets but the kit comes with rollers. You could run the 305HR with the right gears, compression ratio, carb, and headers.

Honestly the reason nobody knows about the 288hr is because if they are looking for the performance that you get with that size cam most people will just go with a solid roller for all out performance which enables them to run even a bigger cam with the same driveability of the 288hr.
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Old 03-18-2008, 10:27 AM
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Quote:
Originally Posted by Double_v23
Yes you will need roller lifters, yes they will need to be captivated by the bar across both of them. the picture shown with the link you supplied shows flat tappets but the kit comes with rollers. You could run the 305HR with the right gears, compression ratio, carb, and headers.

Honestly the reason nobody knows about the 288hr is because if they are looking for the performance that you get with that size cam most people will just go with a solid roller for all out performance which enables them to run even a bigger cam with the same driveability of the 288hr.

Alright. To answer your q's, i'm gonna be running most likely 3.73 in the back, MAYBE 4.11, but I want to use the highway at times. The max lift, I think that comes with the AFR heads, is .600, which would be fine, but I could get the higher lift valve springs if needed and probably will just for some reassurance. gonna go with a 750cfm speed demon or a holley equivelant. approximate weight would be around 3500 with engine in it, but haven't weighed it out yet.

how often do you have to retighten the rocker arms with a solid roller? how can you tell when it needs to be readjusted?

Last edited by mrdreex; 03-18-2008 at 10:37 AM.
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Old 03-18-2008, 11:09 AM
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xr288hr

I know someone that has a 70 Nova with about the same setup as you. He has 4.1 rear ratio, 383 flat tops, AFR 195, Victor JR, 750 DAP Holley, nice ignition, fiberglass hood and fenders. He drives the car on the street daily. His cam is a Comp XR292R with roller rockers. It is a solid roller but he has not had any problems with lash. This cam is wicked and to boot he runs low 11s in a quarter! Gas mileage is horrible! If it were my car I would go one step below with the XR286R.
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Old 03-18-2008, 11:53 AM
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Quote:
Originally Posted by Quarter Flash
I know someone that has a 70 Nova with about the same setup as you. He has 4.1 rear ratio, 383 flat tops, AFR 195, Victor JR, 750 DAP Holley, nice ignition, fiberglass hood and fenders. He drives the car on the street daily. His cam is a Comp XR292R with roller rockers. It is a solid roller but he has not had any problems with lash. This cam is wicked and to boot he runs low 11s in a quarter! Gas mileage is horrible! If it were my car I would go one step below with the XR286R.
sounds wicked. I can't wait to get mine rolling. I already expect to be getting crap mileage, and I think i'm probably going to go with 3.73 gears, so it may offset that bad mileage a bit. if I were to buy this set, would any of you happen to know if the lifters that it comes with have the followers already on them, or would I have to buy those separate?
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Old 03-18-2008, 12:02 PM
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xr288hr

I bought and installed this kit for him. The kit I bought was Comps complete kit and came with followers, and everything else I needed.

Bob
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Old 03-18-2008, 12:09 PM
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Quote:
Originally Posted by mrdreex
how often do you have to retighten the rocker arms with a solid roller? how can you tell when it needs to be readjusted?

Not as often as some people think, I have a solid roller from Bullet cams in a 496 BBC I adjust the rocker arms on about the same schedule as I change the oil. If you use good locking rocker nuts you may have to do it twice a year (if you drive it all year)

You will get used to the sound of the rockers clattering and you will know if one or two are loose by the way the engine sounds. I was checking them every month or so and they never really changed so I just check them with the oil changes and they are never more than .002-.004 loose.
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Old 03-18-2008, 12:15 PM
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Quote:
Originally Posted by Double_v23
Not as often as some people think, I have a solid roller from Bullet cams in a 496 BBC I adjust the rocker arms on about the same schedule as I change the oil. If you use good locking rocker nuts you may have to do it twice a year (if you drive it all year)

You will get used to the sound of the rockers clattering and you will know if one or two are loose by the way the engine sounds. I was checking them every month or so and they never really changed so I just check them with the oil changes and they are never more than .002-.004 loose.
wow, lol, ok then. I was told you had to readjust them every 200 miles or so. so much for that. I guess it really depends on how much/hard you drive it.


Where would you suggest buying a cam kit, with everything provided? summitracing has most of their comp cams and kits available until the 4th, and meh, I don't want to wait that long, =)
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Old 03-18-2008, 01:04 PM
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Yeah, from my experience, common misconception. But let me tell you the performance is on a whole different level.
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Old 03-18-2008, 01:21 PM
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Quote:
Originally Posted by Double_v23
Yeah, from my experience, common misconception. But let me tell you the performance is on a whole different level.
Although I could go bigger with a solid roller, it would be mostly out of my RPM range, correct?
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Old 03-18-2008, 01:34 PM
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It depends on the cam, I run mine around town at 2000 and it pulls to 7k just fine. If anything it would extend the operating range of your motor. Instead of being 3000 to 6000 it might be 2000-6800. Because of the longer duration and faster opening and closing of the valves. You also don't have to worry about lifter pump up and valve toss. As long as you use the appropriate springs.
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Old 03-18-2008, 03:08 PM
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Quote:
Originally Posted by mrdreex
Hey all, it's another cam question! First off, here is my setup:

- 383 4 bolt SBC
- All forged internals, flat top pistons (around 10.4-10.5 c/r)
- AFR 195cc Heads
- Super t10 4 speed

Going to be a mean street car, and I want to go as big as possible. My question is, am I limiting myself with this cam? Could I get away with more lift/duration on the street and not compromise the power brakes/steering (not like it matters)? What is the 'biggest' that I could go and still keep it street worthy? Also, with hydraulic roller cams, do you need the 'lifter followers' as to keep it from moving inside of the lifter bore? I would assume that you would need that for roller lifters. This is what I had in mind:

http://store.summitracing.com/partde...8&autoview=sku

Thoughts?
Whether or not you need the lifter retainers depends on what kind of block you have. If it is 1987+ and has the provisions for the stock retainer, you don't need the retrofit lifters and their fancy retainers, saving lots of money. If you're retrofitting an earlier block then yes, you'll need them.
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Old 03-18-2008, 03:25 PM
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Quote:
Originally Posted by Double_v23
It depends on the cam, I run mine around town at 2000 and it pulls to 7k just fine. If anything it would extend the operating range of your motor. Instead of being 3000 to 6000 it might be 2000-6800. Because of the longer duration and faster opening and closing of the valves. You also don't have to worry about lifter pump up and valve toss. As long as you use the appropriate springs.
It is a pre-1987 block. =(

Alright, I have another question. Cam buttons. Is that all I will need to stop the walking effect? What length would I need for the button? I've seen several, ranging from .680 in to .945 in.
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