Thread: How much Cam split?

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Guys I am gathering parts for my BBC build. Its a 454 .030 over block. 10:1 compression. Intake is an Edelbrock RPM air gap. Have not purchased/decided on a carb as of yet. Trans is a TH400 and will have approx 3200 stall. Rear gear 3.73. Car is a 66 Chevelle and will be 90% street and is not a daily driver.

Heads are GM 049 castings that have had port work and 2.19/1.88 Ss vavles installed by a reputable builder. Flow sheet was provided with heads and reads as follows:

28" 4.350 Bore

Good Port Bad Port
2 162 2 162
3 228 3 222
4 286 4 270
5 311 5 302
5.5 313 5.5 311
6 313 6 318

I have not decided on a cam as of yet but Im leaning heavily towards a hydraulic roller camshaft. My question is how much split should I look to utilize in a cam I choose? I hope I have provided enough information for some insight/advice.

Thanks for any replies in advance,
Scott

Pat, Tech, nobody has an opinion or wants to share thier knowledge?

My opinion is not nearly as valuable as the others mentioned and I figured pat would be on this one... my feeling is that you will want a 112 to 114 LSA for street use but I am far from the expert in this regard.

2 cents is about all it's worth,

-Chris

you could run a 112 but i would lean more to a 110to108 if your at 10to1 a 230/238@050.621/.621 lc 110 or 234/242 @050.585/.585 lc 112+AV.4 ON 106 or 234/242@050.621/621 lc108+AV.2 ON 106 .you could run abit more dur i used the 238/246 @050 .621/621 on 108 and have used it at 112 on a 396 stick car you can move out theLC if your goin to spray it. here is big as i would go for your build 246/254 @050 .621/621 LC108 AV +2. on 106 if you could get to 10.5 CR and have 3200+stall they are all the Erson Cams HR ENERGY PLUS CAMS with new lobe all BUT the 585 lift cam

Pat; do you think his stall will be big enough with that cam?
Kurt

Originally Posted by vara4

Pat; do you think his stall will be big enough with that cam?
Kurt

what cam ? they all will work smaller dur @ 050 will work better if stall is not what he think he has

Pat: I was talking about the one you said was as big as you would go.
{here is big as i would go for your build 246/254 @050 .621/621 LC108 AV +2. on 106 if you could get to 10.5 CR and have 3200+stall they are all the Erson Cams HR ENERGY PLUS CAMS with new lobe all BUT the 585 lift cam}.

Originally Posted by vara4

Pat: I was talking about the one you said was as big as you would go.
{here is big as i would go for your build 246/254 @050 .621/621 LC108 AV +2. on 106 if you could get to 10.5 CR and have 3200+stall they are all the Erson Cams HR ENERGY PLUS CAMS with new lobe all BUT the 585 lift cam}.

WELLLLLLLL the book said it should work3000to3500stall i have that cam in a 4/7 swap 496 guy never said any thing about the stall just the back tires but sounds very good

Actually the cam specs I was leaning towards is as follows:

292/300
241/249 @ .050
625/625
110 LSA

I just didnt know how much split is required for the cam with the perfromance of the heads. I was under the impression that a motor utilizing for example a good set of AFR head will not need as much split because the exhaust flows so well...and on factory casting the exhaust falls short of the intake and therefore using a larger split helps. Then I was also under the impression that if you were using a 5000 rpm limit street car not really much need for a split, where as if your gonna spin a motor for 7000 rpm and the purpose of the motor is HP then a great split is required. Again this was what I understood but wanted the experts opinions, thats why I started the thread.

Originally Posted by 30-A Rider

Actually the cam specs I was leaning towards is as follows:

292/300
241/249 @ .050
625/625
110 LSA

I just didnt know how much split is required for the cam with the perfromance of the heads. I was under the impression that a motor utilizing for example a good set of AFR head will not need as much split because the exhaust flows so well...and on factory casting the exhaust falls short of the intake and therefore using a larger split helps. Then I was also under the impression that if you were using a 5000 rpm limit street car not really much need for a split, where as if your gonna spin a motor for 7000 rpm and the purpose of the motor is HP then a great split is required. Again this was what I understood but wanted the experts opinions, thats why I started the thread.

i really do not look at it that way

When the post involves a BBC, I usually don't answer it at all. Pat McCarthy knows waaayyyy more about them than I do, so I defer to him.

I will join in on this one, but only to post a tutorial from Iskenderian so that you have a contrarian point of view. You know me, always the contrarian.

Please scroll down and read Tech Tip 2003 here.....
http://www.iskycams.com/techtips.php

[QUOTE=techinspector1;362002] You know me, always the contrarian.

QUOTE]

Oh man, no way!!!!! Heck, I always figured you were mild and easy going like me!!!!!!!!!!!!!

[QUOTE=Dave Severson;362010]

Originally Posted by techinspector1

You know me, always the contrarian.

QUOTE]

Oh man, no way!!!!! Heck, I always figured you were mild and easy going like me!!!!!!!!!!!!!

hey string the pot dave when you should be building chevy headers

[QUOTE=pat mccarthy;362012]

Originally Posted by Dave Severson

hey string the pot dave when you should be building chevy headers

Awwwwww come on, even slaves get a water break!!!!!

building headers?????? I forgot---I got two sets to do before I get to work on my car---if I could only find my welding helmut---and magnifiers