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Discussion Starter #1
Looking at the Comp XS282 and the XS290 solid FT cams for use in the 383 I am planning. Here is the build:

350 Block 509 010/020
Scat 4340 Forged crank
Scat 4340 ProMod 7/16" Rods
SRP flat tops
Canfield 215cc heads 65cc CNC chambers, as cast ports
World Motown single plane intake
Should be right at 11:1 SCR

With the XS282 my DCR would be 8.66, a bit high.
With the XS290 my DCR would be 8.33 which based on what many have said should be ideal.

I would still like to be able to run her on 93 on the street maybe with the timing dialed back a few degree. At the track it will get a mix with race fuel. My goal is to be as close to 500/500 NA and get my 3750 sled into the 11's. The car has power brakes but I am thinking I may need to add a vaccum pump at some point.

ANy opinions on these cams or suggestions for something better that you guys may have personnal experience with in a 383 would be appreciated.

Tom
 

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I am running the 282hr in my 355 mule. Running the numbers with a -16cc Srp piston and 64 cc heads, Pats program tells me I need to stay where I am. Called Comp and thats the cam they recommended although to conserve some of my dcr, I was leaning towards the XR274.
Sounds like you are wanting to bleed off some compression to run pump prem? I dont have all of my combo complete at the moment .
 

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Discussion Starter #3
Don,

Yep that's the idea, bleed enough to keep it pump gas friendly if possible but not get so big that it gets soggy on the bottom end. Wanted to go with a HR cam but cannot justify the $$$ and could use those $$ better elsewhere. My builder says he gets good pricing on Comp stuff so that is where I am starting however I am certainly open to suggestions.

I plan to drop off the block and other misc parts with him at the end of this week or early next week so he can get parts on order, that is why I am trying to firm up my cam decision.
 

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Tom,
I am putting together a similar combo and I went with the XS282S from comp because I didn't want to go overkill in the lift dept. I also am running this combo on the street and only have a 2800-3000 converter.
So we will see in a few weeks what happens.
 

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Tom, Are you getting rid of your 409sbc for a 383???
 

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Discussion Starter #6
Yes I am ditching the 409 and going to a 383. I liked the power of the 409 but both of the builds on it were pretty short lived. Would take too much time to go back thru the issues I had with it. I have a good 4.000" bore 509 010/020 block that will make a great foundation for the 383. Gustaf Engines in Moline, IL is going to do the build for me. If someone is interested in my 817 2 bolt 400 block that is '0' decked has the mains line honed and studded I will be getting rid of it, will need to go .060 over most likely.

Tom
 

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Discussion Starter #8
Dave........good looking ride and an awesome picture of it launching!!

At 13:1 the XS282 seems too small, I wonder what your cranking compression was? No way you were running pump gas with that cam and compression, right? What cam did you go up to? What is the weight of your ride?

Tom
 

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Discussion Starter #10
Highhat.........how do you like the xs290? General driveablity around town? Is this a daily driver for you or just a weekend bruiser. What rpm do you idle it at and how is the vaccum at that idle level? R U running Pbrakes? Automatic or manual trans? ANy idea what the cranking compression might be? What year and weight Camaro do you have this combo in?

Tom
 

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yes, the xs282s was small for my combo, I stepped up to a comp with 264/276 @.050" and .570/.590 lift. I run straight race fuel at the track but i do get away with mixing it with premium on the street. i have dart pro 1 215 heads with 2.05 valves, running .044" quench. I think my car weighs in around 3350 lbs. I ran 11.46 at 118.8 after the cam swap and am looking to knock off (hopefully) another .3 with chassis tuning. and thanks for the compliment on the car.
 

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It's in a 73 corvette at I think 3280lbs. Only use it on the weekends. Idle is fine at 900-1000. I have TH400 tranny and power brakes. Vacuum is 11-12in. Cranking compression is around 180.

here is an idle video someone else asked for:
Highhat.........how do you like the xs290? General driveablity around town? Is this a daily driver for you or just a weekend bruiser. What rpm do you idle it at and how is the vaccum at that idle level? R U running Pbrakes? Automatic or manual trans? ANy idea what the cranking compression might be? What year and weight Camaro do you have this combo in?

Tom
 

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Discussion Starter #14
I does sounds great in the video, actually a bit mellower than I was expecting. The vaccum will certainly work my power brakes and at 180psi cranking compression should be plenty pump gas friendly. How is the throttle response under load and bottom end torque? My Camaro has an extra 500# to you Vette so torque is pretty important. Thx for the info and the video clip!!

Tom
 

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Crisp throttle, with Victor Jr., HVH supersucker 4-hole spacer, and Holley 950HP. 501 RWTQ on Mustang Chassis dyno, with 3500 stall

I does sounds great in the video, actually a bit mellower than I was expecting. The vaccum will certainly work my power brakes and at 180psi cranking compression should be plenty pump gas friendly. How is the throttle response under load and bottom end torque? My Camaro has an extra 500# to you Vette so torque is pretty important. Thx for the info and the video clip!!

Tom
 

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Discussion Starter #16
Just recd my new Motown single plane today and I have a Holley HP750 that was originally build for my 406 with a 259 @ 050 cam so it should work wellon the 383. Ultimately I think to make more power on the bug end I will need at least an 850 or maybe a 950. Like the sounds of 500 ft lbs at the wheels......starting to get pretty pumped about this build. Thx for all of the info!

Tom
 
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