427+ SBC...cam selection what works
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 1,146
Likes: 2
From: Albuquerque NM
427+ SBC...cam selection what works
I'm looking for help from other big CI SBCs. My motor is a 4.125x4 GM motor, AFR 227cc competition ported heads on the way, and a ZF6. The intake is of course a Miniram.
aLthough I looking hard at solid rollers I haven't given up on hyd rollers. (Several of the comp hyd profiles actually exceed lift and area of the streeet roller variants).
So with a starting point of 248 deg at 0.050" for intake and 254 deg ar 0.050" for exhaust. Right now my durthers (sp?) are to grind this at a 116 lobe separation. What are you guys seeing run well with this combo? Suggestions?
aLthough I looking hard at solid rollers I haven't given up on hyd rollers. (Several of the comp hyd profiles actually exceed lift and area of the streeet roller variants).
So with a starting point of 248 deg at 0.050" for intake and 254 deg ar 0.050" for exhaust. Right now my durthers (sp?) are to grind this at a 116 lobe separation. What are you guys seeing run well with this combo? Suggestions?
Melting Slicks
Joined: Oct 2000
Posts: 2,627
Likes: 8
From: Drag racing junkie Va.
ZD1,
I ran the Comp Cams 248/254 hyd. roller in a 420 w/MR/auto. for a while in a track only C4, I think you'd better call CC for another cam if it's going to be street driven. My LSA was 110 or 112 instead of the 116you mentioned but it had a ratty idle and almost no vacuum for the brakes, and if you have emissions forget it!
My previous LPE 219 worked great and had better manners, even the CC305 might work better. Others have said the CC306 was radical in the 350-383s but in a 427 it might work out.
Good luck,
Dave
PS-this is how the car worked!
I ran the Comp Cams 248/254 hyd. roller in a 420 w/MR/auto. for a while in a track only C4, I think you'd better call CC for another cam if it's going to be street driven. My LSA was 110 or 112 instead of the 116you mentioned but it had a ratty idle and almost no vacuum for the brakes, and if you have emissions forget it!
My previous LPE 219 worked great and had better manners, even the CC305 might work better. Others have said the CC306 was radical in the 350-383s but in a 427 it might work out.
Good luck,
Dave
PS-this is how the car worked!
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 1,146
Likes: 2
From: Albuquerque NM
Drifting
Joined: Aug 2001
Posts: 1,500
Likes: 0
From: Holliston MA
Cruise-In VII Veteran
I've put the Comp HR 236/242, 110 lsa, .520"/.540" w/ 1.5's in an 11:1 406. Pretty hairy cam for a daily driver. Took work to get the '7727 (speed density) ecm to live with it. The extra cubes would tame it a bit.
You planning on an aftermarket ecm or stock ?
Dave, that cam you mentioned on the 420 - stock ecm or aftermarket ? My personal experience is that the aftermarkets deal with bigger cams more easily than the stock ecms.
You planning on an aftermarket ecm or stock ?
Dave, that cam you mentioned on the 420 - stock ecm or aftermarket ? My personal experience is that the aftermarkets deal with bigger cams more easily than the stock ecms.
Melting Slicks
Joined: Oct 2000
Posts: 2,627
Likes: 8
From: Drag racing junkie Va.
Slo,
GM ECM, however, I never could get the thing to idle clean plus run on the top end. Almost no vacuum which made it pig rich 'cause the AFPR wouldn't close. I picked up an Accel and a FAST system but never got around to putting one of them on the car. Went to a proven carb this year to break in the new engine, I'll try the EFI again when I have the time
to play with it.
Dave
GM ECM, however, I never could get the thing to idle clean plus run on the top end. Almost no vacuum which made it pig rich 'cause the AFPR wouldn't close. I picked up an Accel and a FAST system but never got around to putting one of them on the car. Went to a proven carb this year to break in the new engine, I'll try the EFI again when I have the time
to play with it.Dave
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