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#1 |
Registered User
Join Date: Jun 2016
Location: Central California
Posts: 13
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Power problem after cam and intake swap
I recently did a cam and intake swap on my 72 with a pretty much stock 350. I put in a Summit 1102 cam, about .421 lift on the intake and .442 on the exhaust, nothing really radical. The intake I put on is an Edelbrock Performer, again nothing crazy, the intake that was on there before was an Edelbrock Torker II, which didn't really fit the rest of the engine combination. I reused the stock valve springs, which I suspect is my problem. I've got nearly no power after about 2600 rpm. Before the swap it pulled well past 3000 rpm all the way up to 4000. Other things in my combo are mid length headers, true dual exhaust with magnaflows, 600 cfm Edelbrock carb, HEI, a TH350, and 3.08 gears. I just swapped the metering rods in the carb to see if that was the issue, but it didn't help. It pulls pretty well up to 2500 rpm, just falls flat after. Anyone got any ideas? Is it the valve springs like I suspect?
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1972 C10 Cheyenne w/350 |
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#2 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Power problem after cam and intake swap
What’s your timing like?
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#3 |
Registered User
Join Date: Jun 2016
Location: Central California
Posts: 13
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Re: Power problem after cam and intake swap
I don't know anything about the timing curve, the weights and all that are untouched in the distributor, I've got about 16 degrees base timing.
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1972 C10 Cheyenne w/350 |
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#4 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Power problem after cam and intake swap
Is that 16 set with the vac advance plugged off?
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#5 |
Registered User
Join Date: Jun 2016
Location: Central California
Posts: 13
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Re: Power problem after cam and intake swap
Yeah that's with the vac advance plugged off.
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1972 C10 Cheyenne w/350 Last edited by mchyphy; 02-02-2018 at 12:24 AM. |
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#6 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Power problem after cam and intake swap
When you adjusted your valves before you fired it up for the cam break in, how far did you adjust the rockers. And when you adjusted them did you use the twist the pushrod method or did you use the wiggle the slack out of them method.
And how long and at what rpm was the cam break in done? |
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#7 | |
Registered User
Join Date: Jun 2016
Location: Central California
Posts: 13
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Re: Power problem after cam and intake swap
Quote:
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1972 C10 Cheyenne w/350 |
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#8 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Power problem after cam and intake swap
Pop the valve covers off, check for rockers that aren’t moving enough.
You mighta flattened a lobe or two. You needed to be at high rpm and stay there for 20 minutes. The high rpm ensures the lifters rotate and wear in to the lobes. Any initial idling is a lobe killer. |
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#9 |
Registered User
Join Date: Jun 2016
Location: Central California
Posts: 13
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Re: Power problem after cam and intake swap
Man, I really hope that's not the case. I'll check em out tomorrow when I got the time.
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1972 C10 Cheyenne w/350 |
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#10 | |
Registered User
Join Date: May 2011
Location: mich
Posts: 655
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Re: Power problem after cam and intake swap
Quote:
by letting it idle the cam does not get the splash and it gets dry in a big hurry during this all so important time. I dare say you wiped a couple of lobes if not all. |
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