SSC

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.

ME Leigh

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?

JP84Z430HP

You may wanna grab the casting numbers from the Vortec heads, and from the LT1 heads.

I'm not sure if the 305 vortec heads differ from the 350 heads. Anybody know about this for sure?

Looks like with your setup, the only change you would need to make is putting on a vortec 4 barrel intake.

ME Leigh

Yes the Vortecs differ, what are the numbers off both?

SSC

I finnaly got a good connection:rockon:

I'll post the numbers today, I just havent had a chance to yank the vortec out of the truck or pull the valve cover off my engine.

F-BIRD'88

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.

http://www.castheads.com/

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?

SSC

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!

ME Leigh

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.