Cam question for the experts [Archive] - Chevelle Tech

: Cam question for the experts


bw72chev
Apr 17th, 05, 4:10 PM
I purchased a CraneCam solid roller a few years back Part no. 138111. My plan at the time was to build a semi-streetable 468 BB 1/4 mile car which can be driven to the track and local car events. The problem is I wound up with a 1969 396 +.060 4 bolt. The current pistons are domed but not sure of the CR.

My question is what can I expect if I use this cam? What will installing the cam 4 degrees retarded do for me? I have my theory, but like to hear the truth. What type of aluminum heads would you guys suggest? I've researched and like the AFR 305 but not quite sure. I am not sure about the seat pressure rating of 250 #. And would like to be able to use whatever heads purchased on as many short block combinations as possible in case I run across another short block in the future.

I do have the recommended springs for the cam installed on a set of steel heads never used.

Cam Specs:
Lift: 708 Int/Exh
Cam Timing: @0195 300 Int/310 Exh
Cam Timing: @.050 262 Int / 272 Exh

Spring Requirements:
Closed 160 lbs @ 1.968
Open 490 lbs @ 1.308

Wolfplace
Apr 17th, 05, 7:20 PM
I purchased a CraneCam solid roller a few years back Part no. 138111. My plan at the time was to build a semi-streetable 468 BB 1/4 mile car which can be driven to the track and local car events. The problem is I wound up with a 1969 396 +.060 4 bolt. The current pistons are domed but not sure of the CR.

My question is what can I expect if I use this cam? What will installing the cam 4 degrees retarded do for me? I have my theory, but like to hear the truth. What type of aluminum heads would you guys suggest? I've researched and like the AFR 305 but not quite sure. I am not sure about the seat pressure rating of 250 #. And would like to be able to use whatever heads purchased on as many short block combinations as possible in case I run across another short block in the future.

I do have the recommended springs for the cam installed on a set of steel heads never used.

Cam Specs:
Lift: 708 Int/Exh
Cam Timing: @0195 300 Int/310 Exh
Cam Timing: @.050 262 Int / 272 Exh

Spring Requirements:
Closed 160 lbs @ 1.968
Open 490 lbs @ 1.308
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In every case that I have retarded a cam it has hurt power regardless of what the magazines tell you.
When I read retarded to me this is less than what the lobe separation is or for a 110 separation cam 4 degrees would be a 114 intake centerline.
I have never seen this work worth a damn.
I do not consider a cam retarded if it is ground with 4 degrees of advance from the manufacturer & installed four degrees retarded from there. I consider this installed straight up.
In most cases cams seem like from 2 to 6 degrees of advance & this is where I would always start unless I had information to the contrary.

On to your cam,,
Unless you have a ton of compression it is too big for a 396.
I personally don't like the seat pressure recommended, I prefer a minimum of 200/500 for most solid rollers.

I think with this cam in a mild 396 you will have an engine that will be a slug until about 4500-5000 rpm or so & retarding the cam will make it worse.:(

The 305 head is an excellent head but it would be happier on a 454 than a 396.
It would work well but I think the Brodix RR oval would be a better match in an aluminium head.
If this engine will be replaced with a something larger in the near future the AFR will leave you a lot more room to grow.

If you email me & I can probably save you a few dollars on either
head as I have pretty fair pricing on them :)

bw72chev
Apr 17th, 05, 8:15 PM
Thanks Mike, I sent you an email.