Hi, I am a first time poster as i have recently acquired a 1987 Pontiac Firebird with a 350 in it. Looking at this site for mods, i found out about putting vortec heads on this engine to increase performance. I currently have access to a 4.8 and 6.0 vortec engines that have the engine, but no intakes. Will these heads fit on the 350 i have in my Firebird??? If not, what size vortec heads will i need to purchase? I have looked through the faq and searched, but haven't found this question, so if you need to move this topic, feel free to.

Thanks for all help,

87bluefbird

 

The heads from "4.8" or "6.0" engine will not fit your motor at all. These are from a totally different motor than the one you have in your car.

You could use the "vortec heads" from a '96-2000 model year 5.7L "L-31" truck motor. The casting numbers on these heads end in "062 or 906" all others are not The heads you want. "Vortec heads" require a "vortec intake manifold"
Stock Vortec heads require modifications to run them in a high performance appliation. You can buy used or new GM L-31 vortec heads and have them modified for better springs and high valve lift or you can buy modified "upgraded heads" or you can buy aftermarket vortec heads from RHS ( racing head service). you can buy a vortec intake manifold from Edelbrock, Professional Products, or GMPP or Holley/Weiand.

 

Thanks for clearing that up for me F-BIRD'88, i really appreciate it. Will any other modifications be needed except for the different intake manifold to get it running?

 

All you have to do is bolt them up and use vortec intake gaskets and intake if you have a stock or just a little bigger cam and they make great power even with out a cam.