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Do I need aftermarket valve springs.

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1K views 6 replies 4 participants last post by  hdmarsh77  
C
#1 ·
My 103 build is getting off to a late start. I just got my heads flow tested after my own port job. I think the numbers are OK for a bagger. I have a woods tw6g cam 5.10 lift. Stock valves and springs. TP rocker boxes and roller rockers. Fueling super pump and support plate. SE (Jim's) stroker crank timken bearings. SE high tinsel head studs, SE cast flat top pistons SE 50mm throttle body. Am I overlooking anything
The flow numbers of the heads.

Readings at 28" WC Temp 72 Baro 30.18 humidity 84% 85 cc chambers

Lift --------- Intake ---------- Exhaust
100 ---------- 71.5 ----------- 60.0
200 -------- 145.0 ---------- 122.2
300 -------- 207.1 ---------- 169.7
400 -------- 234.3 ---------- 190.6
500 -------- 251.0 ---------- 200.8
600 -------- 258.1 ---------- 207.4
 
#3 ·
"Do I need aftermarket valve springs?"


You're using a bolt-in camshaft. Normal operation would not need anything other than the stock springs. If you are going to operate the engine in the higher rpm range, above 6000, or you're into speed shifting and there might be a chance of missing a shift...I would recommend a spring set up that would have a bit more pressure.





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C
#4 ·
Any brand of springs stand out as good ones. I should say that these are 07 heads with the beehive spring. With cast pistons I probably do not want to turn it any harder than 6000. I have a set of forged pistons but most people do not like them for street use. I have to admit I enjoy the on ramp drag race.
 
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