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-   -   gt40 alloy heads, valve spring problem (http://www.clubcobra.com/forums/small-block-talk/67372-gt40-alloy-heads-valve-spring-problem.html)

dbn04 02-22-2006 10:54 PM
gt40 alloy heads, valve spring problem
 
need a bit of help with a problem ,it seems the valve springs that came with the heads are weak and motor has a power dip at high revs (around 4500-4800 rpm) this shows up on a dyno , it also seems to have a flutter (only word i can think of) when you excelorate and back off a little . a couple of mechanics and the 2 dyno guys say its the valve springs. of course ford motorsport say they dont have problems with there springs and wont replace unless i prove which ones are failing , so my question for you folk out there is 1 : have any of you had probs with the same 2 : should i use another type of spring from someone else,.
any help would be appreciated .
darren

mstngjoe 02-23-2006 08:00 AM
What cam are you running?

dbn04 02-23-2006 02:27 PM
http://www.fordracingparts.com/parts...rtKeyField=899
mstngjoe, the link above will show you the cam specs, its the one that ends in b303

mstngjoe 02-23-2006 06:58 PM
That's a relatively mild cam with a peak rpm of 5100.

Have you/mechanic/dyno guy verified the valves are properly adjusted?

HighPlainsDrifter 02-23-2006 07:53 PM
B303
 
Hi,
I ran the B303 cam with stock springs for 3 years,works fine,the cam only makes power to 5,200 rpm.
I would check the distributor advance rate.
Good luck,
perry.:MECOOL:

dbn04 02-23-2006 08:10 PM
thanks for the replys ,as for your questions every electrical part has been replaced and adjustments checked several times , :CRY: very frustrating

mstngjoe 02-24-2006 07:06 AM
Quote:
Originally Posted by dbn04
thanks for the replys ,as for your questions every electrical part has been replaced and adjustments checked several times , :CRY: very frustrating
At this point, pulling the springs and checking their tension would seem the only way to verify that was the problem. Or eliminate them as the problem. ;)


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