Hi Guys, I'm new here and was hoping to get some help with a cam suggestion for my 71' olds 350 from a group that knows a lot more about oldsmobiles than I do. I've owned numerous Chevys, Pontiacs and Buicks but I've only owned 1 Olds, a 68' Delmont 88 425 and growing up in the midwest sadly that was my winter car in the mid 80'a as a teenager.

I have a rebuilt 71' 350 with #7 heads, new stock valves, hardened seats, Edelbrock Performer Rpm, MSD Distributor w/ 6AL box, hooker 1 3/4 full length primary tube headers with a full length 2.5" exhaust with X pipe. I think the #7 heads are 64 cc combustion chambers from the factory. It has factory replacement 14 cc dished pistons and I was told it had .026 thick head gaskets not the .043. I aquired the engine from a friend that bought a 71' Cutlass with the engine and rebuild TH 350 but he decided to put an LS in his Cutlass. So I have a fresh 350 that I've already mocked up then installed in my 62' GMC/C10 for this year or so to cruise and have some stoplight fun with. I plan on building a serious Olds 455 in the future. The only thing missing in the SBO is a cam. The Comp cam that was in it destroyed a lobe during break in before my friend bought the Cutlass. The engine was completely torn down, extensively cleaned and reassembled.

My 62' GMC with the Olds 350 in it weight is 3446 lbs.
Rear end is a Factory Dana 44 posi with 3.54 gears.
Rear tires are 26'' tall
The convertor is only an 1800 stall
I've read every post I could find on a good low compression 350 Olds cam but haven't really seen anyone say "I've used this cam and it worked really well" the 350 Olds is a bit of a mystery to me. The short stroke, long rod, big bore, 1.77 rod to stroke ratio etc seems to be what you would normally build for a higher rpm hp application instead of a relatively low rpm torque engine.

So with the relatively low compression, new stock rockers and other parts listed what would you guys recommend for a cam? I definitely don't want a Chevy grind but something that was ground specifically for the Olds. I'm thinking something like this:

Advertised duration (int/exh) around 257/263

Duration at .050 around 214/220

LSA/ICL around 112/108

Gross valve lift around (int/exh)
.485/.490 I think .500 is the max with stock rockers.

I know that's vague without timing events... but something in that general area I think should make decent power if the overlap is kept relatively low. Should be good from 1000 - 5200, and push the cylinder pressure up to help the lower static compression as rpm goes up.

Thanks in advance for any suggestions.

Roger

 

Your cam specs sound good to me.

One thing to note is the heads are not 64cc (that is the NHRA blueprint spec for minimum volume) and most are around 68cc.

 

Thanks Fun71 for the clarification on the #7 heads cc's. I've seen anywhere between 64 - 69 cc's 14 cc dish and as much as .028 in the hole. I've seen the invoice on this engine rebuilt and it says skim heads to clean up surface but no dimensions written in the comments. If I was having it built, it would have a pistons in it to raise it up to 0 deck and the heads would at least be pocket ported and gasket matched with BB valves but right now I'm going to work with what i have. Other than Mondello who's good with understanding oldsmobile cams? With my Buick stuff in the 80's Kenne Bell was the place to go. I know that Sig Erson ground the cams for them.

 

May be an opportune time to review this thread...
Cam Selection for 350 Olds

 

X 2

If they took a skim cut to clean up, your pistons are probably still below the deck.
We have an engine builder on here who is good with Olds engines and cams. PM Cutlassefi and he could help you.
Note: I am NOT a fan of Comp Cams because of cam and lifter failures.

You might find a 455 could be handle in your pick up. A pick up lacks weight over the rear wheels and if the nose is down like yours, a 350 Olds will smoke the tires.
......Just my two cents worth.

 

Thanks, Vintage Chief, I've read it a few times and I've also built a few different engines with 8.5 to 1 static compression that ran well with decent power considering that constraint. I just don't have any good information about a SBO. Honestly reading that thread just makes me want to pull the engine out and do all the things needed for a 400 + hp 350 SBO. Again flat top pistons, 0 deck, pocket port and gasket match ports, BB valves etc.

 

I agree with you about Comp Cams. I also know the trucks are light in the rear. I put a complete 85' C10 front crossmember in it already with 92' IROC Camaro brakes and 73 - 79 C10 could be order with a 350 olds diesel so the motor mounts where pretty easy except I moved the engine back about 3.5% without cutting the firewall and I was also able to use the driveshaft out of the Cutlass without modification other than a moog conversion u-joint for the Dana 44. The next plan is a 4 link. My brother is an incredible chassis builder. He completely built and owns the fastest 4 x 4 chevy truck in the world. It runs a 541 KB Oldsmobile with a PSI screw blower that I designed and built for over 24 years. He's currently building a street 4 x 4 for Farm Truck from street outlaws. If you want to check it out, Google Miss Missery race truck. It makes about 62 lbs of boost and 4000 hp and has run 3.90 @ 191 in the 1/8 mile @ 2800 lbs breaking rocker arms starting at about 150'. Couple of bad crashes online also, when we were trying to figure out how to stop the front wheel from spinning at 160 mph and shooting him into the guardrail.