'98 4.3L transplant to '87 Chevy Pick Up?

Intake ports are different on heads but I believe Elderbrock make a manifold for this conversion. The Vortec engine flows better in heads and cam timing is a bit better but it shoulf work if you get the right manifold for it and use all your TBI hardware. You should pick up 20 or 30 ponies in the process too over a stock TBI motor.

The fuel injection system is the major reason for the increase in power. The only gain would be because its a newer engine with less wear on cylinder walls and cam etc. And perhaps smoother running because of the balance shaft I believe this engine has. The manifold will not work from the 87. Edelbrock has a street legal performer manifold the stock throttle body will bolt to on your current set up. Comes with a mail in Post card that will get you at no charge a new chip for the comp. Supposed to give a 6/10 of a second increase in the 10-70 mph acceleration.