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Ok, I have a set of vortec heads, and am looking to get them ported and polished. What kind of HP gain am I looking at in doing this, and is it really that benneficial? Also, i want to put 1.6 roller rockers on and i know that in order to do that I need to have the valve seats ground out and I need bigger springs. Anything else I need to do other than that, and can anyone reccomend good springs with a comp cams XE cam .487 - .490 cam? Anyone have any suggestions to anything else? Thanks
I've got a scan of a flow chart by David Vizard somewhere. I think if you click on the link for my exhaust clip, you'll find it in the folders somewhere.
If you want to use that XE274 with 1.6 rockers, you need at least 986 springs, and it might not be a bad idea to step up to 987s, especially if you're going to be running it past 6000 RPM. Same price, a little better spring.
__________________ "So many Mustangs, so little time..."
I would leave the intake port as is and port and polish the exhaust port for this motor.
The stock vortec port and 1.94" valve is hard to beat as it comes.
porting will only help at real high lift. which you don't have.
Just do the exhaust ports and set the springs, guides and
studs up for your new cam.
Use a thin head gasket to help maximize your final cr with your "base crate motor" (dished pistons)
Porting or other mods to the bowls and runners has been shown to hurt flow!
__________________ LT1 headed LG4 305 beast! Comp Solid lifter XS-262-10S, 1.6 Roller Rockers, 10.2:1, Holley 4160 600cfm, modded Weiand 7502 intake to fit LT1 heads____ Custom cylinder head cooling. Weiand 8208 Short Water Pump____TH-350 3 series 3.73 with 2 series posi and spacer____ Hedman Hedders 1 5/8 headers and Y-pipe 3in Exhaust, Dynomax 3" Bullet muffler ____Moroso Ultra 40 Wires ACCEL HEI Super Coil ____Competition Engineering 3120 Bolt-on SFC's____Homemade: Wonderbar, solid tie rod sleeves, Aluminum LCA and Panhard Rod with spherical rod ends, alternator and PS bracket, Strut tower brace, and Decoupling torque arm with telescoping link.
3000lbs
"The liberty of a democracy is not safe if the people tolerate the growth of private power to a point where it becomes stronger than their democratic State itself. That, in its essence, is Fascism - ownership of government by an individual, by a group or by any controlling private power."
-FDR
"If this were a dictatorship, it'd be a heck of a lot easier, just so long as I'm the dictator."
-- President George W. Bush
During a photo-op with Congressional leaders on 12/18/2000.
If you look at that chart I showed (or buy the book) you'll see that just doing pocket porting (bowl blending) does very little to the Vortec heads.
IMHO, I'd agree with ME Leigh that you'd be better off not messing with them due to chancing amature mistakes, like nicking the valve seats, or hitting a water passage. But that's me.
The ONLY thing I'd do is back cut that valves 30*. That's been shown to help. Although word around the water cooler is GM now sells them that way. You'd have to ask (Scoggin-Dickey or Jim Pace Performance Parts) if the ones you're buying are that way.
with the xe 274h and the re done vortecs it should make peak right around 5900....go to the car craft website and look for a backissue on this buildup called "400hp vortec engine"
this is the same motor i am building and it made 442hp@5900 and 452ft lbs at 4400rpms
Hey AJ_92RS,
Do you have a bigger version of that article? I can't read any of it. Or if you know what issue of mag it came form, I could look it up on the net.
Thanks,
__________________ Joshua Johnston
1991 Z-28 -- SOLD
1985 C-10
Originally posted by johnsjj2 Hey AJ_92RS,
Do you have a bigger version of that article? I can't read any of it. Or if you know what issue of mag it came form, I could look it up on the net.
Thanks,
Once you click on the link, you can click on the pic also. That'll bring it up to full size.
Doing that fills my 17" flat screen. Granted it's a bit fuzzy, but legible.
