Cam Selection Help
I have that 65 Malibu project and have a
4 bolt 454 with flat top pistons. I am removing the
stock heads cast#10114156 which apparently are not
that great. I have a set of 063's 68-69 396, 427 heads
that I am getting rebuilt. I want to put them on to bump up
the compression a little. My question is these 063's are close
chamber 101cc. .with flat top piston won't the valves hit the
piston? because on older motors like the 396 the piston were
domed on half the top so that the valves did not tap the piston.
I know guys that have done what I want to do and it takes a low
compression, low power motor and snaps it up pretty good. What cam
should.can I run that will maximize the power and give it a nice rupity
lope idle? Small block are easy to cam, but getting a lope out of a BBC
is hard unless you go all out.
Please help me. The heads are getting rebuilt right now and can get the
bowls port for $400 which seems spending to me.
Thank you a lot
Please read this tech information from Iskenderian. It covers your question and more......
fastest: i had a very similar 454 as you and here is what i did.
I'll assume you're using TRW L2377F30 flat tops. They have two opposing single intake valve reliefs on the top (-5cc)
Assuming stock (.022) deck clearance and +.30 over bore and using a GM LS-6 .022" shim head gasket (GM dealer item), your cr with 101cc heads will be 9.08:1
If you were to shave the heads down to 95cc (about a .060" cut) your cr using the .022" head gaskets would be 9.52:1 Just right for a street pump gas BBC.
The Old GM L-78 395-375hp LS-6 454-450hp "143" camshaft was and still is a very sweet street performance cam in a BBC Specs are 284-284 242-242@.050 .520" .520" lift. The valve lash is .024"-.028" "hot"
The idle sound is very sweet. It drives and runs very smooth with strong power.
No problems with valve to piston clearance. Needs dual coil performance valve springs ( Crane #99895-16) Crane sells a "blueprinted copy" under pn#969961.
Use a dual plane hi rise "RPM" manifold, 3.73 or 4.10 gears and a 11" "3000stall converter".
i would use a 2.19"x 1.88" valve set on these heads. (requires just minor chamber deshrouding)
Cam Selection for 063 heads
"F-BIRD'88" Thank you
About the piston...I am not sure what they are it is a .030
over stock motor. In fact I have not pulled the old heads off
yet, but I assume they have the valve relief notches.
So the "143" cam is a selection you can get through CompCam
or Crane? or would a guy call the dealer and ask if they can get
one for a 1970 LS-6? The LS-6 had rect port heads mine 063's
are oval, but are still pretty good heads.
Again...thank you for the info and if you have more I would be
in debt to you.
You can buy this factory BBC solid lifter muscle car cam from Crane #969961 or Comp cams #11-106-3
among other companies. GM also sell the Crane cam with a GMPP part number.
The original PN 3863143 OEM GM cam is no longer stocked by GM.
(the crane cam is the exact replacement)
The .022" GM head gaskets are application: 1970 Chevelle 454-450hp "hi perf"
(LS-6) They can look it up. The modest .500" net valve lift allows using stock rocker arms.
Once your oval port heads are ported a bit with the larger valves, they will make very good torque and power.
The key is blueprinting the finished compression ratio. 9:1 is not enough.
9.5 to 10:1 is just right.
Isky cam #396245 Z-45 is another similar and good overall alternative choice for a sweet street BBC. Either will give you the idle sound and performance, without getting too carried away and racey.
Cam/Head CR Combo
Again "F-BIRD'88" thank you. You have apparently
a lot of experience which is very helpful to all.
Well I am go to drop my 063 heads of tonight with
some direction to the machinist in regards to decking
them approx .060" to reduce cc's in the chamber slightly.
I need to pick the cam/spring selection so the can do their
job though. With all the selections not sure which one to go
with. Believe it or not never ran a Crane, always Comp or Isky.
Summit Racing Magazine does not list Isky cams though.
Which would offer the most benifit and meanest sound to my
454? I do know that having a nice lopy runner does not mean
more power...I definetely want both.
Summit sells all the Isky Cams. Not everything is in the summit paper catalog.
Summit sells all the cams I mentioned.
The Isky #396245 will have a slightly more rumpity idle than the LS-6cam
Tighter 108LSA on the Isky cam. (little more overlap) 114LSA on the LS-6 cam. (A little less overlap).
Both, are very nice BBC street cams.
just enter the cam part number in the Summit racing online search box to see it.
F-BIRD'88 thanks for the info.
I will trust your knowledge even though I don't know you.
Hopefully the Isky #396245 comes in a package with lifters,
springs or offers the package.
So am I to understand this is a solid lifter cam? that I can still use
my stock rocker arms?? as you stated.
What does the "Z-45" mean with the Isky 396245 cam? Back in the day
BBC 396 engine offered 375 horse hyd lifters and the corvette version
being the 425 horse with solid lifters 50 more horse with just solid lifters.
Anyway..I am going with the 396245 and I appreciate the help a lot.
One more question..."what happens if I pull the existing heads off this engine
and the flat top pistons have no valve relief notches? just plain old flat.
The 396-375hp motor used the exact same "143" solid lifter cam as the 427-425hp and 454-450hp motor.
same cam in all these motors. the 396-350hp used a smaller hyd cam.
The Z-45 is the camshaft grind number. Download the Isky cam catalog and read it. Call Isky cams if you don't under stand something. Thats what they are for.
Use the recomended springs+ retainers and solid lifters. The retainer to seal clearance must be checked on your heads. .060" at full lift. rocker to stud clearance must be checked on your rockers. (usually good for .540" lift but not more) The Isky cam will have a .512" net valve lift. This and the GM LS-6 cam are "bolt in" without issues with the right valve springs on the old 60's era heads.
I;ve never seen a BBC piston without valve reliefs.
GM used to sell a very very good drop on factory BBC LS-6 valve spring but I don;t think its available any more.
Last edited by F-BIRD'88; 02-20-2008 at 12:55 PM.
Cam vs head Selection
I have the catalog and am on line with Summit right now
I see the 396289, 396255, 396266 nothing on the 396245.
Isn't the problem with solid lifters that you are always adjusting
the rockers? I just want to run the plain old 3/8" pushrods, stock
rockers, nice intake, headers and this solid lifter cam. Looking for
the right set up for weekend romping not daily drivers...(well maybe not)
you know how that goes. My goal is to make my 65 Malibu into the
Z-16 version clone with this 454 instead of the 396.
Sorry if I seem ignorant with specs and numbers. I can pull engines, heads,
cams, rebuilds, clutches vertually anything ,but I lack in the match numbers
for the optimum output. That is why I appreciate your advice. We have narrowed it down to the 396245.
not sold by summit as a cam+ lifter set. order the cam and order the solid lifters
use the recomended isky springs.
The valve lash will need to be checked periodicly (usually when ever you do a oil change) twice a year.
If you want to create a realistic sounding Z-16 clone this (or the crane blueprint) is the right cam. A hyd cam will not give the right muscle car sound.
if you drive your car more than race it I recomend the LS-6 (Crane) cam. the overall driving impression is very good. GM did their homework on this one.
Last edited by F-BIRD'88; 02-20-2008 at 01:34 PM.
Cam vs Head Selection
I printed outthe info...cool.
BBC are hard to get that beefy lopy sound
is this 396245 going to achieve that? to where
your sitting at a light and your antenna is bouncing
back and forth 6"
I had a speed shop build a 396 with 292 CompCam and
it was surprisingly pretty stock sounding and I had dome
pistons, ported close chamber heads, nice intake headers etc..
the lift looks good on this at .530 but lift doesn't equal power or
This is not a race cam. I thought you wanted a " hi performance street cam".
The LS-6 has a nice "rumpity" but civilized idle.
If you want a "pro street bad *** race" cam, this is not it.
The comp 292H magnum cam has a "rough racey idle" The idle is more aggressive sounding that the GM LS-6 cam.
Unless you had some other "292 cam" in it. (the 280H magnum is pretty mild in a BBC) If your oid 396 did not have a radical, rough idle, it did not have a 292Hmagnum cam in it.
If you want a bad *** racey cam that works with the stock rockers used Crane #134261 "Fireball 326". Needs 10:1 cr minimum 3500+ stall and 4.10's++. It's racey.
I think I did say I wanted a street cam, but a racey
street cam. I do think the Crane will work because of
the CR I will end up with after I get my heads decked
.060"-.070". the lift on the Crane will probably be too much
for the clearance.
The solid lifter cam (Isky) you suggested will do I guess.
Can't expect too much with 9.0-9.5 CR. As long as is apparent
there is some beef and lope. Besides with the 65 she is pretty
lite weight and with the 454 I should be happy I hope. Just having
the solid lifters and the 396245 will bump it up a few notches.
|Recent Engine posts with photos|
|Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)|
|Thread||Thread Starter||Forum||Replies||Last Post|
|Cam selection for pickup||Chevy21||Engine||8||12-23-2008 10:00 AM|
|lunati cam selection help.||73camaro||Engine||15||02-02-2007 06:30 AM|
|cam selection||ajh86||Engine||9||12-14-2006 10:24 PM|
|Cam Selection...Please help!||1BDMNTY||Engine||22||03-28-2003 02:11 PM|
|HELP cam, intake and carb selection?||sniper4570||Engine||5||01-15-2002 09:16 PM|