[Squidward]

Originally Posted by steve25

Do this simple test out.

1). Get the motor fully warmed up.

2)advance the initial timing at idle until the start has a hard time cranking the motor over, I mean a noticeable hard time.


3). Back 4 degrees of timing off of whatever that is .

4). Take the car out for some full throttle romps while listening for ping .

Are you smiling maybe now after the test drive?

Actually, this right here is a simple tune method! Love it. Most distributors add 20-22 mechanical. And I have found that the starter chug point on my engine takes place at about 18 degrees initial. So using the above method, the initial gets dialed back 4 degrees. So you end up with 14 initial, 34-36 total. Vac advance adds whatever 12-15 degrees you want. But this will make an engine run.

I run 14 init, 20-22 mech, with somewhere around 12 or 14 for vac advance. So I can validate that what Steve points out is in perfect alignment with my timing.

Thank you Steve. Gonna put this in my back pocket. With that, you don't even need a very accurate timing tab or balancer mark.

[steve25]

Welcome !

Of course if this works hopefully the engine can still be set to a low enough idle without a stumble being produced.

[Formulas]

Originally Posted by steve25

Do this simple test out.

1). Get the motor fully warmed up.

2)advance the initial timing at idle until the start has a hard time cranking the motor over, I mean a noticeable hard time.


3). Back 4 degrees of timing off of whatever that is .

4). Take the car out for some full throttle romps while listening for ping .

Are you smiling maybe now after the test drive?

This method does nothing to ensure total initial and mechanical timing are in spec which is an important factor especially with stock cast pistons

[steve25]

Yes, that’s for certain but there’s no need to extrapolate out from what I posted that he should beat the hell out of the motor for 5 minutes straight either !

In fact when this test pan’s out that for instance that your timing light,and or your balancer is off by 4 to 6 degrees you can feel the torque and response difference even before full throttle.

Also initial and book spec’s go out the window once the stock Cam gets changed, and especially in conjunction with a motor that has had aluminum heads slapped on it 60k mile stock block.

[HWYSTR455]

As an example, I ran 16 initial, 8 vacuum, 32 total mechanical, and my engines loved it.

I ran that exact setup on several diff engine combos and it was a baseline for all builds going forward from a certain timeframe, roughly starting in the 90s. Both iron and aluminum head builds.



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[steve25]

I do fully agree however that if he starts to make decent power and the cylinder pressure that goes with that, then the motors cast pistons will be his Achilles heel .

[grivera]

Originally Posted by HWYSTR455

As an example, I ran 16 initial, 8 vacuum, 32 total mechanical, and my engines loved it.

I ran that exact setup on several diff engine combos and it was a baseline for all builds going forward from a certain timeframe, roughly starting in the 90s. Both iron and aluminum head builds.



.

I’m surprised your iron-headed engines didn’t like the usual 34-36 degrees. What compression?

[HWYSTR455]

Originally Posted by grivera

I’m surprised your iron-headed engines didn’t like the usual 34-36 degrees. What compression?

The last iron head one I believe was 9.98 SCR, typical large valve small chamber heads, think they were 16s, but would have to check.

Usually, the aluminum heads like a little more, in the 34-36 range, but my 461 round port e-heads (10.68 SCR I think) still ran best at 32. I did try 34-36 with it, and even tried a bunch of diff heat range plugs, but it still ran best overall at 32.

I'm running my 535 with 340cfm round port E-heads at 34 right now, but I see no diff between 32-36 with it. I think it's at 10.35 SCR, so it would make sense it wants more, but haven't found that to be true. I am still in the tuning phase on it though.



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[HWYSTR455]

My 535 cranks at 16 degrees, and have idle set to 24, so very similar to previous engines for me.


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[b-man]

Interesting 19 year old thread on 350 engines, of particular interest is the post linked talking about a 9-second 350 in a lightweight Astre (Canadian Vega) race car that also ran 11-flat in a first-gen Firebird.

https://forums.maxperformanceinc.com...50#post2635494

[400 Lemans]

Look at Cliffs post #6 on this thread. He had installed plenty of Crower cams. Save yourself anymore hassle and advance it.

[400 Lemans]

Look at Cliffs post #6 on this thread. He had installed plenty of Crower cams. Save yourself anymore hassle and advance it. https://forums.maxperformanceinc.com...ghlight=degree

[b-man]

Without having to go back and read through the whole thread again, did you degree your camshaft upon installation or did you just install it dot to dot?

Either way if you didn’t advance it now is the time to degree it and advance it.

Timing sets as well as new cams can have the keyways machined a bit off from where they should be, so it’s not wise to just throw it in there with the dots aligned.

Here’s a 350 HO of sorts I put together on the cheap for my brother for his ‘69 Firebird, it had the 068 cam advanced 4 degrees:

https://forums.maxperformanceinc.com...3&postcount=55

It really felt more like a 400 than a 350. There’s definitely something fundamentally wrong with your 350, they’re really not bad engines at all.

[Jay S]

As I recall this 350 engine the pumping compression was in the 190s on the good head. Hopefully square up with the other bank now (was 160s on the other bank before machine work)…Cam timing being very wrong is a long shot.

I don’t know what the issue is. Could be something was overlooked, a bad quality part, or something simple that is wrong just waiting to be corrected, it has happened to me plenty of times, and when you make a lot of changes it is easy to have happen.

Just a few glitches we have had lately.

New Napa HEI module layed over at 5000 RPM, a problem because peak power is past 6000.

New Summit Timing light off 14*. Found out at the race track when it ran like crap.

On 2 different Holley 750HP series carb ($950 carbs). NEW, completely off on the factory tunes. Both have been very disappointing. And still trying to get them dialed in, gaining on one, but the other is back on the shelf and we installed a cheap 800 cfm reman Jet QJet, and it completely blew away the Holley HP. How humiliating, beat by a FrankenJet after a day of trying to get it corrected.

[steve25]

Wow that does suck Jay!

I hope you’re not into sky diving?

[scott70]

Originally Posted by HWYSTR455

The last iron head one I believe was 9.98 SCR, typical large valve small chamber heads, think they were 16s, but would have to check.

Usually, the aluminum heads like a little more, in the 34-36 range, but my 461 round port e-heads (10.68 SCR I think) still ran best at 32. I did try 34-36 with it, and even tried a bunch of diff heat range plugs, but it still ran best overall at 32.

I'm running my 535 with 340cfm round port E-heads at 34 right now, but I see no diff between 32-36 with it. I think it's at 10.35 SCR, so it would make sense it wants more, but haven't found that to be true. I am still in the tuning phase on it though.



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Same here,,, I’ve run round port E heads,, probably 4 different numbered iron heads with solid roller to hydraulic flat tapper and they all liked no more than 34 total,,, most on the Dino liked an average of 32. I played with them at the track also and ran the best times around 32. I’d advance it to 34 or 36 but they wouldn’t go any faster.

[steve25]

I don’t want to go back thru this whole string of post, but if he’s at a high altitude here’s what I am thinking .

With those heads he has and the amount of intake lift that he is running with that Cam then even if he was at sea level the added port area of those heads would make for a wash between the loss of port velocity from stock and the 10% of added intake flow of the KRE heads over a stock 155 CC intake runner iron head.

And I am not even factoring in the larger port area of the intake manifold he’s running .

With aftermarket heads on a motor of this CID I would want a Cam of .550” intake lift rolling around in my block, not the .455” intake lift that he has.

Go look up the string of post from around 2005 that Jim Hands was putting up and what his 455 intake lift a 4100 lb wagon was turning with 170 CC 260 cfm reworked iron heads.

And the 350 of the OP of this string has 22% less CID then Jim Hands 455 does.

[NeighborsComplaint]

Your cam timing is retarded. You need to degree and advance the cam. As a kid, I put a Mellings 300H cam (.512 lift/300 degrees adv duration) in my ‘66 390 Fairlane GTO. Installed dot to dot it ran so gutless it was slower than stock. Just past 3500rpm it would wake up like you flicked a switch. Spin the tires from a stop? In my dreams. I could barely clear the intersection, nursing the car along and slipping the clutch.

After exhausting “easy fixes” (running only mechanical advance and plugging the Holley’s power valve and up-jetting) to address symptoms of low manifold vacuum, I bit the bullet and had a mechanic neighbor (who crew-crew-chiefed for an injected B-gas dragster) show me how to degree a cam. Mine came in 6 degrees retarded when dot to dot. When I bought the cam (from Bud Richter’s shop who campaigned the Gold Digger Funny car w Gary Bolger), Richter told me to advance the timing 4 degrees so the cam was a full 10 degrees. At the time I had no idea what he was talking about and thought he meant advance the ignition timing. lol

We didn’t have multiple slot keyways in those days and Chevys were the only ones with adjustable timing sets. You advanced or retarded the camshaft w offset woodruff keys for Mopars. They only came in -2, -4, +2 and +4 so I was SOL. I purchased and installed a Factory Ford 428 SCJ Dragpack cam, checked it when installing and dot to dot was right on spec. The difference in drivability and seat of the pants hp and torque was like night and day.

[Jay S]

He state he checked the cam timing and it was running 107* to 108*. That was also confirmed when it pumped 190 lbs compression. There should be no reason to advance if more than that, especially with a 2800 stall.

With how it is set up, it should not be a dog at the 2800 stall converter with the low first gear in a 200R4, it should roast the tires. If it can’t do that, it probably is pretty unimpressive up top too. I can’t say what that the issue is, whether it is an issue in the season short block or something else. But overall, I really don’t see the mix match of parts in this build.

Some estimate numbers from my Dyno Sim, it could vary some in the real world, but really not by a lot.

1969 350 HO with headers, 10:1, 48 heads, RA 3 cam 068, pretty close to the factory rating of 330HP@5200 and 380 tq

330 HP @ 5000, 401 TQ@3500

Same set up, only switching to KRE D ports with the 068 with 2.11 valves

357 HP@ 5500, 409TQ@3500

All things the same, but switching with a Crower 60916 with KRE’s with 2.02 intakes 236 CFM

379 HP@ 5500 406 TQ@ 3500

350 but with flow numbers from JIM HAND’s ported 6X with 1.77 exh from his book, same things as above with a 60916.
402 HP@6000, 402@3500, 411 peak@4K

Same 350 combo by with flow numbers Jim Hands Edelbrock RPM round port he tested.

396 HP@6000 411@4000

The 6X-4 heads Jim Hand had last on his car were also superior to the ones in his book, they flowed almost 270CFM. I don’t recall the specifics anymore on what E heads he tried, I just recall he lost a some power against his worked over D ports.

[darbikrash]

Originally Posted by Jay S

He state he checked the cam timing and it was running 107* to 108*. That was also confirmed when it pumped 190 lbs compression. There should be no reason to advance if more than that, especially with a 2800 stall.

With how it is set up, it should not be a dog at the 2800 stall converter with the low first gear in a 200R4, it should roast the tires. If it can’t do that, it probably is pretty unimpressive up top too. I can’t say what that the issue is, whether it is an issue in the season short block or something else. But overall, I really don’t see the mix match of parts in this build.
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I have to agree with just about all of this, there are tens of thousands of 350 SBC's running around with similar combo's with great low end performance.

The 350P has a basic flaw as compared to the SBC 4.00" bore, the 3.875 bore is small enough, and the factory valves are big enough, that valve shrouding is a significant issue. This shows up specifically as a loss of low end torque.

I'm dealing with this right now with a 350P I'm building.

The stock 350P block (usually) has eyebrows cut into the top of the cylinder to try and help with this. However, the factory eyebrows are not really suited for high lift cams, as you are severely restricted in valve lift due to the potential for the valve to hit the block. And if the lift is small enough to clear the block (say .490"-.510" max) shrouding comes into play- which hurts low end torque. Note the exhaust valve block clearance is much worse than the intake valve clearance.

The 350P I am working on has about .600" exhaust valve lift. I made a fixture to mount a Goodson grinding wheel above each cylinder to dress the block eyebrows. I 3D printed parts of it and machined other parts. It's driven by a handheld drill.



I put a 3D printed plug with O-rings in each cylinder to prevent any grinding dust from going into the ring pack. The plug presses all the down to the bottom of the cylinder on top of the piston, with the eyebrow dressing taking place above it.




On the subject of valve shrouding on a 0.030 oversize bore 350P from ChatGPT: