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Username Post: need help for picking a cam.        (Topic#348820)
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
12-22-17 06:06 PM - Post#2718807    

ok i know this has been done a million times but I and new to this and would like some help with cam choice.

I have a stock short block ls1 with afr 215 heads with 0.040 compressed head gasket,
pistons
are 0.006 above deck which gives me 0.034 quince.

compression ratio is 10.7 , has comp cams adjustable timing set , 25 % under driven pulley set , stock rockers , 102mm fast
intake
with 100mm bbk throttle body . headers are 4 into one , primary pipes are 1 7/8 into a 3" chamber then reduces to 2 1/2" exhaustsystem.

160 thermostat / rear end is true track centre with 3.7 gear ratio with a 245/40/18 wheels. car weight is 3790 pounds. at this point I have a comp cam xr 265 hr which is making 387 hp at the wheels.

now I have good flowing head I would like a better cam to suit this set up.

has a 4l60 trans with a 2000 -2200 still .
it will also need to work with a 125 shot of nos.

any help would be great and thanks.



 




Shepherd 
Frequent Contributor
Posts: 1335

Loc: Lake George, NY
Reg: 11-11-15
12-22-17 07:00 PM - Post#2718813    
    In response to bjautos

Anything we suggest is subjective, as our expertise cannot, for the most part, match the tech advice from a major cam manufacturer, not a sales person, make sure to speak to the right person. Of course your intended use is important in this equation. Btw, what are you running now?



Edited by Shepherd on 12-22-17 07:20 PM. Reason for edit: No reason given.

 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17178
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
12-22-17 07:33 PM - Post#2718816    
    In response to Shepherd

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
12-22-17 09:47 PM - Post#2718824    
    In response to grumpyvette

ok thanks , there a lot to read,
this is a street / strip car and would like to keep it street able, was hopping to go low 11s and aiming for around 420-450 hp at the wheels and hit it with a shot of 125 nos. not sure how close I would get to low 11s but that's what I like aim for or better.






Edited by bjautos on 12-22-17 09:49 PM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 3361

Reg: 04-15-05
12-23-17 12:39 PM - Post#2718862    
    In response to bjautos

Too bad about the too tight .034 quench distance, the .045 gasket would have worked, as would a .050 one.

Expect problems with the too tight quench.



 
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
12-23-17 02:10 PM - Post#2718867    
    In response to IgnitionMan

thanks for you reply I feel my .034 quench is fine. I always aim for around 35 - 40 and never had any problems with it.

cam I'm running now is a comp cam xr265hr so not very big.
have done 12.879 @ 108 miles and 8.3 on the 1/8 .
this is a street / strip car.
just looking for a cam that will work well with my set up.




 
IgnitionMan 
Valued Contributor
Posts: 3361

Reg: 04-15-05
12-23-17 05:07 PM - Post#2718884    
    In response to bjautos

I don't, too close, once the piston decks build up a carbon face, way too close, forces cooling mixture out of the quench area, and overheats upper rings.

But, that's where detonation begins, and detonation is mostly silent, so, no reason to think you have any idea as to what is actually going on in the too tight quench distance, until it is too late.



 
65_Impala 
Very Senior Member
Posts: 4021

Reg: 12-29-02
12-26-17 07:41 AM - Post#2719028    
    In response to bjautos

I'd talk to Tony Mamo (Mamo Motorsports) for a custom recommendation. It wouldn't be that much more and he's done a lot of work with LS engines and AFR heads so he knows what works with them.

Generally speaking, I'd say you could go with about 10-15* more intake duration and at least 0.6" lift though.

The quench is just fine as long as the pistons don't kiss the heads.



 
IgnitionMan 
Valued Contributor
Posts: 3361

Reg: 04-15-05
12-26-17 08:10 AM - Post#2719029    
    In response to IgnitionMan

Quench is too tight, enjoy the problems, and adverse piston deck/top ring issues that it will cause.



 
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
12-30-17 03:07 AM - Post#2719401    
    In response to 65_Impala

thanks for your time mate.
was looking at going to this cam XER273HR what is your throughs on this cam with my set up. any help from tony would be great.




 
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
01-04-18 12:28 AM - Post#2719944    
    In response to bjautos

any one




 
65_Impala 
Very Senior Member
Posts: 4021

Reg: 12-29-02
01-04-18 11:18 AM - Post#2719987    
    In response to bjautos

Did you call Comp and ask them what they recommend?

That cam should give a nice performance improvement over the cam you already have. The XER series is supposed to be fairly easy on the valvetrain.

Cam Motion has some interesting LS cams. Maybe the Titan 4 would work for you.

Lingenfelter has some interesting LS cams too. Just note these do have fast ramps so they do tend to be harder of the valvetrain.

I'd give all 3 of the the above companies a call and see what they say to use.

Note that the stall converter can become an issue.

Also note that the cam could be larger than that one and make more power, but a suitable duration depends on the use of the vehicle because you can push the operating range too high for street use in a heavy vehicle.



 
rumrumm 
"17th Year" Silver Supporting Member
Posts: 2075
rumrumm
Loc: Macomb, IL
Reg: 10-18-01
01-04-18 03:17 PM - Post#2720012    
    In response to 65_Impala

Agree with Ignition Man on the quench. I would never want to be border-line-okay especially if I was juicing something. But it your engine . . .

Lynn

"There's no 12-step program for stupid."


383 sbc, Eagle, AFR, SRP, CompCams, Edelbrock, FiTECH. Dyno #'s: 450 hp @ 5700, 468 ft. lbs. torque @ 4300.

http://photo.net/photos/Lynn%20Johanso n


 
bjautos 
Forum Newbie
Posts: 64

Reg: 06-25-12
01-06-18 11:18 PM - Post#2720294    
    In response to rumrumm

thanks for every one's input, I drive this car every day with no issues , air flow research recommend a 0.040 head gasket so I'm ok with it.
plus I races this car from time to time. will try these companys
and go with there pick




 
65_Impala 
Very Senior Member
Posts: 4021

Reg: 12-29-02
01-08-18 10:15 PM - Post#2720525    
    In response to bjautos

I can believe AFR would be OK with it. Tony Mamo worked at AFR before going out on his own. He has built many well performing LS based engines and I have seen some of his build write-ups where he used a tighter than expected quench. I recall a build write-up where he build the engine so tight that 2 pistons cracked the ring lands because they kissed the head. So, he fixed the pistons and added something like 0.004" more quench before continuing on with the build. A number of his engines with the tight quench have had many street and track miles accumulated on them so what he did has been proven to works well past the initial engine dyno runs. I'd consider him an expert on using AFR heads to build LS engines since it used to be his JOB doing it at AFR.



 




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