bought an 87 iroc i knew was not original engine.was told had 89 350 vette short block w/double humps on it...whatever ran good .cant read casting # on block but to no suprise is stamped 5.0LG.heads have casting#14014416.is this an LG4 block with L69 heads?if so what cam should i use(tpi) and can i put 1.6 rockers w/o interference issue?(has umbrella seals).

 

LB9's, L69's and LG4's had 416 heads through '86, then the '87 LG4's and LB9's got 081 heads.

Use a computer-friendly cam.

 

so my best case scenario is i have an lb9 w/roller cam and worst case is i have lg4 turd i had in my 83 z28.hhmmm.do you know by chance exactly where the casting # is on block so i can figure out what i have wo tearing it down?i have to say though car runs like a raped ape!thankyou!

 

416 heads were originally used on older blocks with a 2 piece rear main seal (no roller cam- flat tappet only). It's still possible you've got the earlier heads sitting on a later roller cam block, but the first thing I'd check is if the engine has a one piece rear main seal. If it does, you probably have a roller cam in it. If not, it's almost certainly got a flat tappet cam.

 

The casting number is behind the driver side head. If you saw the "5.0", you were close to the casting #. The last three digits (all that are important) are sometimes cast on the side of the block, viewed from under the car.

 

thanks guys ill let you know how i make out.appreciate it!