About a year ago I bought a set of Vortec ZZ5 heads from Pace Parts for my 350 modified TPI.

The engine is basically a ramjet clone, with custom ecm, installed in an 87 firebird.

I installed a ZZ4 cam and Comp Pro Mag Roller Rockers.

My question concerns the valve springs installed in the ZZ5 heads. While not directly specified, from the specs it seems they are 330585 GM springs with 140# @ 1.75” for mechanical flat tappet racing cams.

The recommended springs for the ZZ4 cam are the 12551483 rated at 101# @ 1.78”.

Do I need to replace the springs on the heads to use the ZZ4 cam?
What do I need to purchase and change on the heads to install the correct springs?

The engine will be primary driven on the street and I do not want additional stress on the valve train, decreased gas mileage or starting issues due to the increased valve pressures.

 

Comp makes a beehive spring that will drop right in for around $165, just make sure you get the matching retainers. also, on ebay, there is a company called alex's. they make a drop in valve spring and retainer kit for around $100. i know the alex's isnt an overly aggressive spring, maybe around .500". Im running into the same thing with my vortecs. Good luck, scott

 

More important is the max lift of those ZZ5 springs
Will they handle the 510 lift of the ZZ4 cam?
The ZZ4 /LT4 springs are good to .525