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I dont have the casting numbers here but....
I currently have 1972 LT1 heads and the car runs great but I just got a 97 vortec 305 with sever crank/rod damage "thanks for no core charge GM" and the heads have less then 80k on them. I dident yank the engine out yet but these heads should be better then the Lt1's right? My operating range is only idle to 6200 so the dropping valve size isnt a concern. What type intake or modifications must be made to use these heads if its worth the effort?
Edit: I know all this has been asked before but My AOL connection is shizty lately and searching archives would take a month.
__________________ 1976 SWB C10 3/4 drop, gen VI 454/M3.
1973 Buick Apollo wifes play car. Chevy 383/S3.
I don't think the 305 Vortecs are any good, plus you will need to do lots of mods to them. Keep the LT-1 heads they should be decent, BTW what are the casting numbers?
__________________ 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.
Yes the Vortecs differ, what are the numbers off both?
__________________ 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.
The L-30 305 Vortec heads have lots of hidden potential, but will need some work. They have smaller 1.84 intake valves
and different shaped smaller combustion chambers (58cc).
But the ports are the same as a 350 L-31 vortec port.
The 305 vortec head requires the vortec style intake manifold.
First get the casting numbers off the heads and be sure they are vortecs.
The 305 L-30 vortecs are #12558059 and 12552520
There may be others but these are the common ones.
If they don't have the 8 bolt vortec manifold bolt pattern they're not vortecs.
They will need bigger 1.94 intake valves, some port blending
a new valve job and the vortec spring guide boss height and valvetrain hardware up-grades. 1.60" exhaust valves will work well too.
Brizienski Cylinder heads says these heads are very good once upgraded. He recomends them if ya got them.
For manifolds you have a choice between edelbrock, Gm performance parts and Professional Products intakes.
Professional Products just introduced two new Vortec Intakes.
One is a Performer RPM Air Gap Nock off and the other new one is a single plane racing intake. I recomend the Dual Plane RPM
"CrossWind" #52028 www.professional-products.com
In my opinion these 305 vortecs once upgraded will
be a nice performance gain over your present large chamber
LT-1 heads. You'll have more compression and better flow.
You should hang onto those 350LT-1 heads though. They are worth money to a resoration nut. Especially if they match that 350 motor. They can be modified too to increase performance but the vortecs will be more powerfull.
exactly what are the casting numbers on those LT-1 heads?
Finnaly got off work. The numbers on my LT1's are 897 "8 or 3" 487. These do have factory screw in studs and 2.02 intake valves so they arent the truck heads that have 1.94's and pressed in studs with the same casting number. The vortec's are the 12558059 casting, I do like the beffey springs they have on them but for all the hassle I might just take my old 58cc heads that have already been worked over and 1.94 intake valves and slap them on.
Thnaks for all the info Guys!
__________________ 1976 SWB C10 3/4 drop, gen VI 454/M3.
1973 Buick Apollo wifes play car. Chevy 383/S3.
3973487....71-72...350..........used on 71-72 350 LT1, 75cc chamber
I'm not sure how good these heads are with such a big chamber.
__________________ 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.
" and the heads have less then 80k on them. I dident yank the engine out yet but these heads should be better then the Lt1's right? My operating range is only idle to 6200 so the dropping valve size isnt a concern. What type intake or modifications must be made to use these heads if its worth the effort?
