# Pontiac 1971 350 Cam Upgrade - Looking For Input/Opinions



## 1971LemansWisc (Apr 18, 2021)

I have a relatively Stock 1971 Pontiac 350 with #94 Heads, 4-BBL Quadrajet, 1972 Muncie M20 wide ratio 4-Speed, 3.36 8.2 BOP Dura Grip, Dual Exhaust, 27.4 Tire Diameter 

I have to go in and replace the Crankshaft Seal in the Timing Cover so since I’m going to have the front of the Engine off … looking at just some simple upgrades.

At this time the Budget doesn’t support a decent set of Heads … 2023 maybe.

I have a good 400 Block, but is already reserved for another future project. 

I will replace the Lifters, Push Rods and go to a Double Roller Timing Gears/Chain same time.

Looking at the attached Cam Comparison - I currently have the “W” 483555 Cam.

The 9779066 Cam was used in both 2-BBL and 4-BBL applications in Engines with a 10.5 Compression whereas my 350 #94 Head combination is only rated at 8.0/8.2 Compression Ratio.

I know there are lot of great Cam Manufactures out there - I am looking at the Melling SPC-4 as I believe it most closely matches the 9779066 and isn’t a too radical jump up from the 483555.

I expect the performance bump to be small but worth the effort … still researching resulting Torque/Power Band, Idle RPM and Advance to make this all play nice together.

I want to avoid having the Idle RPM too high - just to achieve a reasonable Idle. 

Thank you in Advance for your input and/or opinions please.


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## O52 (Jan 27, 2019)

Take a look at the 068 (Melling SPC-7) cam. Doesn't require anything special but engine should have over 9.25 compression. 

The best timing chain is the stock morse chain version, and they are cheap!









1959 Through 1979 Pontiac 326 350 389 400 Engine Timing Set-Stock Melling 3-350S | eBay


1959 Through 1979 Pontiac V-8 Engines 3 Piece Timing Set. Pontiac 326 350 389 400 455 Engines From 1959 Through 1979.



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## 1971LemansWisc (Apr 18, 2021)

Thank you for the Timing Chain recommendation.

The Pontiac 9779068 equating to the Melling SPC-7 – this is a great Cam.

My current Compression Ratio with the #94 Heads is only 8.0/8.2 range in order to go to that Cam … agree I should be looking at optimally 9.5 for Compression Ratio.

To achieve that with this 350 Block I am looking at a Head change and/or an upgrade to the Rotating Assembly – Pistons, Rods etc.

Back to my original assumption – I will see benefit going to a 9779066 over my existing 483555 "W" Cam.

To be honest, I don't yet completely understand all the components that go into Engine Design. 

I know the 9779066 Cam was used in a time of much higher Compression Ratios - if it isn't intended to be used in my 8.0/8.2 Compression Ratio 350 I'll just stick with what I currently have.

Thank you for your help.


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## PontiacJim (Dec 29, 2012)

1971LemansWisc said:


> Thank you for the Timing Chain recommendation.
> 
> The Pontiac 9779068 equating to the Melling SPC-7 – this is a great Cam.
> 
> ...


With the lower compression, look at a cam having a tighter 110 Lobe Separation Angle which will raise cylinder pressures (compression). The 068 would be too much for the 350 and low compression - it would work at high RPM's, but be a little soft on the bottom.

The "066" is on a 111.5 LSA, and you have 116 - but that is for the exhaust valve Centerline. Intake is on a 107 Centerline, so add intake/exhaust Centerline and divide by 2 to give you the 111.5 LSA. This cam would be good for low compression. You can use your stock valve springs.

Timing chains are based on opinions - we each have our preferences. I have used the Summit timing chain and gears without issue and they were inexpensive.









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You can go up in price and multi-keyway from there. For the stock valve spring pressure/low compression, this chain should be fine. As you get into higher spring pressures, especially roller cams, you need to step up to a $$better/stronger chain/gears.

Also get a good cam/lifter lube for break in. I suggest a "grease" over a liquid lube that can drip off. I am trying the Driven brand Engine Assembly Grease on my build. You can get this at Summit.


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## 1971LemansWisc (Apr 18, 2021)

Pontiac Jim - 

Thank you, again ... for sharing your knowledge and your recommendations.

The relationship between Lobe Separation Angle (LSA) and Cylinder Pressure (Compression) ... 

This is the Gem, "With the lower compression, look at a cam having a tighter 110 Lobe Separation Angle which will raise cylinder pressures (compression) ... The "066" is on a 111.5 LSA." 

This is the piece I wasn't 100% clear on ... makes sense now for my lower Compression 350 application. 

I'll give the Driven brand Engine Assembly Grease a go.


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## PontiacJim (Dec 29, 2012)

1971LemansWisc said:


> Pontiac Jim -
> 
> Thank you, again ... for sharing your knowledge and your recommendations.
> 
> ...


The 110 LSA is common with the likes of Comp Cams. I used their XE274 can in a previous 8.0 compression 400CI, but had the larger valves/screw-in studs. Used Comp Cams springs and lifters. Engine pulled very good and no issues running pump gas 89.

Your set-up has the press-in studs, so going higher lift and stronger valve springs could cause a rocker arm stud to pull up - generally not and issue, but could become one, so why chance it and have to deal that problem.

The "066" is close enough on the 110 LSA. Then maximize this by dialing in your ignition timing/curve and you should see an improvement in power and response from the engine. Don't be looking for an *big *HP improvements, but you should feel the difference. This is not a magic bullet that will make the car a tire shredder...............you only get that when you add a chrome air cleaner, Mickey Thompson valve covers, and chrome coil, and Cragar mag wheels.


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## O52 (Jan 27, 2019)

And a Buick Air Cleaner decal


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## PontiacJim (Dec 29, 2012)

O52 said:


> And a Buick Air Cleaner decal



I didn't want to mention that one because I figured the decal might add too much power to his engine and bust a transmission or rear end.


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## Boomstick (Sep 13, 2021)

See if you can find a set of 1969 #46 heads (there is a #46 head from the 70's, avoid them, they are not good) They are a great head for a 350. 1.96/1.66 valves so you won't worry about valve shrouding, they will bring you to just over 9.5:1 and they are cheap! There is a set on Frank's Pontiac parts for $375 iirc... I'm putting a set on my 69 350 that ironically enough, currently has #94's on it. Once I'm ready to do the heads, I'm either going with the 068 or 744 cam. Haven't decided yet...


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## LATECH (Jul 18, 2018)

This looks pretty good...









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