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-   -   comp xr270hr roller cam (https://67-72chevytrucks.com/vboard/showthread.php?t=268270)

tcs81281 11-28-2007 09:35 PM

comp xr270hr roller cam
 
is there anyone running this cam(xr270hr from comp) if so how do you like it? i will be running this cam in my 383,9.2compression,87-94centerbolt heads(2.02/1.6valves,pocket ported,76cc.flat top pistons, comp roller rockers,longtube headers,edelbrock airgap intake, edelbrock600cfm carb. should be 400-420hp and about the same in torque from what i have researched. i will be running a th400 or 700r4 later on. should i run a stall converter?:fb:

1968SWBBigBlock 12-02-2007 03:40 PM

Re: comp xr270hr roller cam
 
Looks like an ok combination
I would be leary of the 600cfm, I think it is to small, at least 650 cfm
the only thing I worry about is your 2.02 valves will not help you until you get over 4200 rpm so your best power band is not utilized real well.
Maybe look at a higher lift cam, and a 650 cfm carb

tcs81281 12-04-2007 12:39 PM

Re: comp xr270hr roller cam
 
bigblock, thanks for the comments. i have already bought the cam so ill just stick with it, dont want to get to radical, truck will be a daily driver. comp shows this to be the biggest cam for a stock converter, should i put a little little bit of a converter in tranny? motor should be around 400hp, id be very happy with atleast 375. compared to what i have now(goodwrench 350,around 270hp) i do have a 700cfm edelbrock with maunual choke, guess ill have to play with both and see what works best.

1968SWBBigBlock 12-04-2007 07:19 PM

Re: comp xr270hr roller cam
 
If you want to use a different converter I would not use a large one.
You should be fine with the stock converter for a daily driver.
I think the 700 will win this fight:)

Tom 12-04-2007 08:28 PM

Re: comp xr270hr roller cam
 
2.02s won't hurt the low end, its a 383 breathing threw 170cc intake ports :) You didn't post any specs but comps flat tappets equal out to 220* @.050 when they are advertised at 270* so thats what I'll assume. Thats a great mid range spec for a 383. I agree you need a 750cfm, eddy dosen't make a 700cfm that I know of? The 750 will not hurt your throttle response. If you go with a convertor [I wouldn't for a daily driver] 2200 is the biggest I'd get.

chevy72blu 12-04-2007 08:31 PM

Re: comp xr270hr roller cam
 
Get a stock C4 corvette converter. It'll stall a few hundred RPM's higher without a noticable change in street manners. I actually have one layin around in the garage that you can have for free - shoot me a PM if you're interested

tcs81281 12-04-2007 08:46 PM

Re: comp xr270hr roller cam
 
cam specs: 218/224@.050, 495/502 lift with 1.5 rockers. ill probrally just leave the converter i got in tranny for now when i swap tranny from nova to truck when its done(700r4)

Jim_PA 12-05-2007 05:04 PM

Re: comp xr270hr roller cam
 
Check the compression recommendation on that cam.

Edit; actually comp posted a dyno sheet @ 9.25:1, so I think that means it'd be fine.

http://www.compcams.com/Technical/Dy...0HR-10_001.asp

68c10owner 12-07-2007 12:44 AM

Re: comp xr270hr roller cam
 
are your centerbolt heads the ones that came on the TBi motors? If so they aren`t the best flowing heads. That cam would be a nice torque cam, I would run it for sure. I would rethink the heads though.

tcs81281 12-07-2007 01:07 AM

Re: comp xr270hr roller cam
 
i will run that cam its already bought, and yes the heads are the tbi center bolts with a nice port job with 2.02/1.6valves, its going to be a daily street motor.

68c10owner 12-07-2007 01:11 AM

Re: comp xr270hr roller cam
 
Quote:

Originally Posted by tcs81281 (Post 2475963)
i will run that cam its already bought, and yes the heads are the tbi center bolts with a nice port job with 2.02/1.6valves, its going to be a daily street motor.


I don`t see a problem with the cam, it`s the heads I see as a problem. They have a necked down intake port about 2" down or so and don`t flow for nothing. They should be 64cc`s as well. Whats the head casting number? You`ll make some good torque but you would see 400-425hp owith those heads. Bigger vlves and port work isn`t going to chage the design of the heads and won`t help much. don`t get me wrong, I`m not trying to knock your combo. aside from the head choice I think it will be a great street motor for a heavy truck.


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