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Are these 906 Vortecs Scrap?

1K views 10 replies 6 participants last post by  jokerZ71 
#1 ·
Pick this set 906 Vortecs up for $60.Somebody attempted to gasket match the exhaust ports.Only 1 port was really had any actual work done.You can see how much by comparing to the other port.It only extends into the port 1/2" or so.The rest of the ports are untouched.Scribed lines match up exactly to a stock FelPro exhaust manifold gasket.Should I try to match the other 7 to this,scrap it,or run it as is.I was planning on cleaning up the exhaust ports some anyway.No reshaping,just cleanup,smoothup.I've been told that the area that has been removed from the port actually was there to help prevent reversion?????
 

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#3 ·
They've been magged awhile back & everything else looks good.I got everything with them.I bought a 89 L05 350 with 110,000 miles on it to go in my sons 93 GMC.We're pulling the 6.2 diesel & replacing it with this.It'll be pretty much stock except for a ZZ4 cam & beehive springs along with some tuning & TBI mods. I picked the heads up for $60 along with the cam for $40. The motor with ECM,wiring harness,all sensors,TBI for $350.Gonna be a budget build for sure.This dang 6.2 is breaking him tho.
 
#5 ·
yeah'I don't think it's actually hurting or helping anything.It's matched perfectly with the gasket & only goes about 1/2" in.The guy who told me about the reversion thing isn't a real book of knowledge.He was tryin to trade me out of them for some reworked swirl ports.I think I'll match the other 7 up just for the heck of it.
 
#7 ·
the guy did most of the work on the "slow" side, most of the rush will be coming on the bottom of the pic so prob didnt do much if anything.. only issue is possible turbulence IF the gasket shifts, but it will be minimal - id leave it as is and bolt it on..

was he using the right gasket? that seems like an aweful lot to take out - besides that what intake was he using? maybe he tried retro fitting an older style intake?
 
#9 ·
You can make a comparison beteen those exhaust ports and Pontiac Ram Air IV exhaust ports.

The exhaust ports on the optional 1969-1970 Pontiac Ram Air IV engines were large round exhaust ports with matching exhaust gaskets and manifolds. The RA-IV ports looked great but since they were are only ported 1/2" into the port from the exhaust manifold interface, they flow no better than the exhaust ports on the regular production Pontiac heads.
 
#10 ·
leave the bottom of the runner (top side in the photo you provided) alone and just work on the top area. He took the material out of the wrong side. It won't be a disaster but it won't help anything either and will lower exhaust velocity and scavenging. If youre going to get started on porting them though I'd pop the valves out and do a full job on the bowls at least, and both sides of the valve job. I do that on almost every head I run and while it takes a little time its costs basically nothing but a few cartridge rolls assuming you have a few good carbide bits and a grinder already.
 
#11 ·
leave the bottom of the runner (top side in the photo you provided) alone and just work on the top area. He took the material out of the wrong side. It won't be a disaster but it won't help anything either and will lower exhaust velocity and scavenging. If youre going to get started on porting them though I'd pop the valves out and do a full job on the bowls at least, and both sides of the valve job. I do that on almost every head I run and while it takes a little time its costs basically nothing but a few cartridge rolls assuming you have a few good carbide bits and a grinder already.
The heads are stripped.I'm only reusing the valves.Planning on new springs,locks,retainers.He only went about 1/2" inside the ports.I kinda knew it didn't really help anything as far as flow,but,just wondering if it had actually hurt anything.I'm planning on blending the ridge under the valve job & cleaning/smoothing the runners/ports.I never realized those ports were so mismatched to the gaskets & so much to 1 side. They belonged to the guy's son who left them sitting sometime ago.He has since got married & moved away.He told his Dad to sell it all off to get it outta the way.The ZZ4 cam is brand new.This is gonna be a real tite budget deal to get that POS 6.2 diesel out of the truck.
 
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