385 SBC Cam/Combo Input

[cad]

Hello All,
Im looking for advice on whether there is more left in this year's combo, or if the camshaft is not quite right for the combo.
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It is a S10 and we run 1/8 mile 95% of the season.https://photos.app.goo.gl/arVj1LvkeQVQFs8DA
2900lbs with me
385 sbc. 3.75 stroke, 040 over, 13.1 Wiseco, AFR 220 stock heads, Victor Jr, HVH 1" pheno spacer, 750 mighty demon (74/85 jets)
GZ pump
MSD 7AL3
Running about 38 degrees timing.
We have a data logger - - Air Fuel Ratio is 12.9-13.0 average in 3500' air (1.090 cf)
1.76 glide
6400 rpm Coan (new this year)
Cam card https://photos.app.goo.gl/e64ujme2PVMcy2sS9
---installed and degreed to spec
514 gears
32x14 MT tire

This past spring, we freshened my 385 SBC and changed the camshaft and springs to a Bullet grind and K-Motion springs based on input from a local builder.
We have been 6.42 @ 107.5 on a very good track ONE time this year. The rest of the year has been 6.45-6.50 @ 105.5.

The issue is that last year with a smaller, solid roller https://photos.app.goo.gl/su2fXFxHxyn8K6VGA along with 1.6 rocker arms and my old ATI 5600rpm converter the truck was almost as fast. Last year, I was shifting at 6800 and leaving at 4600-4800, and had the same 60' and were running 6.50-6.60 @ 104.xx.

This year, with the new converter and cam, and shifting at 7300 and leaving at 5600, we havent picked up but maybe a tenth.

Thanks in advance.
CD

[PRH]

When I tried the links to the pics of the cam cards....... it was the same card.

I would assume it’s the smaller of the two:
248/254-112

First thing I’d try is swapping back to the old converter.

[6.50camaro]

The old cam was a much better match for the head, intake, carb combo . The new cam is for about 1000 rpm more . But the heads are 2.18 sq.in. at the pushrod pinch . Which was about maxxed out at 6800 at 7300 the velocity is to high to smoothly flow much more air let alone allow it to go 7800 where I think that cam would be happier. My 2 cents . Dan
Not counting the carb and intake needing to be larger for the new cam.

[PRH]

Okay, got to see the new cam card.

Imo, you took too big of a swing.

Cam swaps often don’t result in the magic happening that many are hoping for.

Plus, in this case there is also another new element mixed into the combo...... the converter.

Its easy to be an armchair crew chief after the fact, but I would have leaned towards a cam just about in the middle between those two, 108lsa, and tried it with the old converter as a first step.

If the intake manifold isn’t ported, there might be a little something to come out of that(or something a little bigger).

[CamKing]

You went from not enough duration, to too much duration.

Here's what I recommend
Cam# SBC, R78440-80440-110
260/268 @.050"
.440"/.440" Lobe Lift
110 LSA

Leave at 4,900, shift at 7,300

[CGT]

The old cam with the new converter may upset you even more.

The old cam was a much better match for the head, intake, carb combo .

I agree

The new cam is for about 1000 rpm more

I have seen cams like cam#2 not be better anywhere than a smaller cam...not even up top. Wrong can just be wrong everywhere sometimes...not saying that's whats going on here but maybe. It did pickup a mph with a looser converter.

[6.50camaro]

I agree ,The converter is a whole other story in its self depending on the cam selection . Dan

[cad]

Thanks everyone. The new converter was not installed until late June. So, I did run the new cam with the old converter prior. I thought the duration was up there before the cam arrived in March...but, we tried it.

[cad]

One other comment, and a question that I just dont honestly know the answer.
The Bullet cam card represents total lift using a 1.6 rocker arm, as that is what we had. What would the effect be swapping to a 1.5 rocker ratio?

CD

[PRH]

Thanks everyone. The new converter was not installed until late June. So, I did run the new cam with the old converter prior. I thought the duration was up there before the cam arrived in March...but, we tried it.

And what were the results?

[PRH]

One other comment, and a question that I just dont honestly know the answer.
The Bullet cam card represents total lift using a 1.6 rocker arm, as that is what we had. What would the effect be swapping to a 1.5 rocker ratio?

CD

Probably not worth trying unless you already own some 1.5’s.

[cad]

Thanks everyone. The new converter was not installed until late June. So, I did run the new cam with the old converter prior. I thought the duration was up there before the cam arrived in March...but, we tried it.

And what were the results?

The 60' was slow .01-.03, and ET was .03-.05 faster than last season with the Comp Cam.