vortec 355 build

L31 880 block, vortec 906 heads, ZZ4 cam

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[hokeplaya05]

did you put the stock intake manifold back on? i am going to rebuild my 96 350 vortec in the spring.

[ATC250Rguy]

Im not a smart ass i just feel obligated to educate others. Ive been in school now for 2 years for high performance engine machining, spoke with Joe Mondello on the phone, been to David Vizards Seminar, and done much of my own porting and flowbench testing. I'm currently machining a 406 that's getting vortecs. The biggest improvement is not the pushrod pinch but the bowls and make sure to stick with 1.94 1.50 valves a 170cc runner cant supply enough velocity through a 2.02 intake valve.

[ATC250Rguy]

Intake ports should also not be polished just the exhaust. You shouldn't use anything finer that 60-80 grit on the intake or you will have fuel puddling on the short side radius of the runner and the intake. You actually want a somewhat rough finish on the intake to supply a homogenous mixture to the chamber otherwise fuel and air will seperate. If you dont believe me use a wet flow bench and youll see. Teflon may sound like a good idea but it'd actually hurt you in wet flow characteristics.

[ATC250Rguy]

Just to clear up some things brought up in previous comments. Gasket matching is a joke, any good engine builder will tell you that. Gasket companies dont have a flow bench and have no idea how large your runners should be. Your intake manifold should be a straight shot to your heads and you should verify this by bolting on the intake with a gasket using a drying dye such as dykem on one side and a non drying layout dye such as prussian blue to port match the intake to the heads.

[mwd92]

i have a 96 stock silverado will i hurt anything if i just put a zz4 cam in or doi have to upgrade other parts

[runninonempiy]

@mudman898989 UUMMM no....Forged pistons require a lot more tolerances and dont last as long as a cast/hyper, for a daily driver.Riddle me this..Why would you ever worry about detonating a 9.6-1 comp. daily driver?Inadequate timing?Nope.its computer controlled.Although your facts are substantial.They do not apply to his philosophy of use. This guy did it right..Actually a little overboard with the porting vs horse power gains on these wonderful as cast heads but hey more power to him..

[jeromeb619]

did u keep the stock valve springs on the heads

[m0nkey1eader]

@mudman898989 dont know anyone thats tried that, i know the gasket port matching's worth 10~ CFM though.

[mudman898989]

@m0nkey1eader yeah itll be a very sweet motor im building everything myself. ive been planning the build for 2 years now. the 383 without buying new heads will be around 2000-2500 thats current machining prices included. im going to port and polish the stock vortec heads. i got the crazy idea yesterday that what if someone teflon coated the ports of your lower intake....strange idea but may increase flow and have less turbulance in the chanbers. its not to ridiculous when you think about it...

[m0nkey1eader]

@mudman898989 sounds like a sweet motor. All that cash, you should get your heads machined. You can get .550 at least, more than that and after-market heads will be on your list. Mind you, for a truck you might want more of a torque cam.

I think RHS makes some vortec heads that can take more lift, but I've got no experience with them.