SD360VTPI Valve spring breakage

I installed one of these motors into my '88 IROC and had the same minor installation problems as previously mentioned. I also broke valvesprings!
Two withn minutes of firing it up and another six in all bent a valve too! (I checked lash prior to firing it up). I talked to SDPC and they said this was an isolated incident. They sent me new springs but one of these failed as well. I swapped to crane springs and have had no problems since. I love this motor and think the power, price, economy and drivability are all there. However I will never touch another LT4 valve spring again. I have a complete set sitting on the shelf, wont use 'em. Has anyone else had this happen with one of these engines or did I just get a bunk set of springs. (Now have 15K trouble free on motor)

Anyone else had this happen?

FYI- I'm no hack mechanic. I am a Pro Marine engineer and diesel mechanic with a degree in Marine engineering. Ive had six 3rd gens and rebuilt more motors than I can count.

88 IROC
SD360VTPI motor
52mm TB
ACCEL runners
Heedeman headers
3 in flowmasters
No emissions
K&N's
Gutted MAF
Cold Air intake
built 700R4
1LE Drive Shaft
3.27 Posi 9 bolt
4wdb
All polyurathane suspension
STB and panhard rod
ROH ZS 17's with BFG 275's

 

I've had my SDPC engine in for a week now--so far so good. *crosses fingers*

 

Hope your engine runs fine. Maybe SDPC had some parts compatability isues to start. Looked it up I have had my engine since 6/02. One of the first I guess. 352 hrs and 17000 miles so far. Love it now but a bad start for sure. If your motor starts to miss pull the valve covers and look for cracked springs that are collapsing. If you get track numbers let me know. The only numbers for these motors Ive heard were from a sales rep from SDPC, Tim said they had a guy whose car was running 12.7 with slicks with this combo. I think you could add .5-1 second for a car on street tires like mine.