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Discussion Starter #1 (Edited)
Guys,
I had my motor freshened up this year and notice it's slow to rev past 6300 hundred.

Make a long story short the heads are cut for 1.550 diameter spring but shop used 1.570 spring. Looks like the counter bore is .300 deep so the spring is really tight in the head to a point that it's pushing aluminum up around the pocket.

Could this cause the problem.

I hadn't ran this motor much before it broke a link bar on a lifter which prompted the need to freshen. Runs great other than it just doesn't pull up to 7k like it did before.

Ran 6.41 @ 106 at 3500 lbs this weekend
BBC 502
Cam .714 lift .260/[email protected] solid roller
Edelbrock oval port 2.25 intake with some work
Old motor rev fine well past 7k but it was a .427
Springs are new Manley set up per spect 221440p

Billy T
 

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Guys,
I had my motor freshened up this year and notice it's slow to rev past 6300 hundred.

Make a long story short the heads are cut for 1.550 diameter spring but shop used 1.570 spring. Looks like the counter bore is .300 deep so the spring is really tight in the head to a point that it's pushing aluminum up around the pocket.

Could this cause the problem.

I hadn't ran this motor much before it broke a link bar on a lifter which prompted the need to freshen. Runs great other than it just doesn't pull up to 7k like it did before.

Ran 6.41 @ 106 at 3500 lbs this weekend
BBC 502
Cam .714 lift .260/[email protected] solid roller
Edelbrock oval port 2.25 intake with some work
Old motor rev fine well past 7k but it was a .427
Springs are new Manley set up per spect 221440p

Billy T

Don't know if its the cause of your problem, but it already sounds like a problem that needs fixed
 

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I dont expect a 1.57" spring to live long stuffed in a 1.55" spring pocket. But u could measure its rate and where its in bind while on the head FYI to see what it can do that way.
 

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Wild Addiction
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i would guess a timing issue, find TDC and re check timing
 

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Discussion Starter #6
Checked with my engine shop and he said they want the springs tight in the head, recommended I run with and without air cleaner and examine the fuel system.

I have a dominator with a drop base and 3 inch filter, this worked good on my 440 but maybe I don't have enough area now for the 502 at high RPMs.
 

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Let's get some more info here....

You had the same heads and camshaft on the previous engine.....??? a 427 cui...???

If so....... ain't no wonder it won't go past 63-6500

P.S. the engine shop telling you that they like the valve springs tight in the head is full of
BS........... unless you want to create spring issues.......(Heat and spring surge)
it will also litter your engine with aluminum..........
 

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Discussion Starter #8
Let's get some more info here....

You had the same heads and camshaft on the previous engine.....??? a 427 cui...???

If so....... ain't no wonder it won't go past 63-6500

P.S. the engine shop telling you that they like the valve springs tight in the head is full of
BS........... unless you want to create spring issues.......(Heat and spring surge)
it will also litter your engine with aluminum..........
I didn't like the way they fit but called them since they set up the valves. This is a new cam for the bigger motor, the motor is not happy above 6300 so I'm looking for the answers now. I can see the spring is pushing aluminum and the spring is tight, going to call Manley tomorrow to see what they recommend. Can't find anything specific on spring to pocket clearance, checked air cleaner clearance and I have a 4.5 inch filter on a drop base, seems like plenty for air flow to me.
Thx
 

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I'm not saying the valve springs are not a problem but If u got the same heads and cam on the new engine than I'm sure u can expect a drop in rpm going from a 427 to a 502.I don't know if 75 cubic inches is worth a 700 rpm drop but don't expect it spin up as high as it did when it was 427
 

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well for a 502 cui engine and them heads and camshaft,.............. I can see why it'd be done a 63-6500......

as far as the springs go...... that's Bull crap that the want to locate the spring with the head/pocket.....

if they continue to tell you it's ok, FIND a new Builder........
 
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