big block buildup

[SCOTT MILLS]

hello all,o.k. heres what i've got,i have a 1972 chevelle ls5 454 block 3999289 it looks like it has new cam bearings,and it looks like its been bored?it dosnt have a crank rods or pistons, i also have a 1978+454 14015445 that was running last year at this time,i took it apart (dont know why) but i rested the crank in the 72 454 i also have a set of 66 427 heads oval port closed chamber 3909902 (need to be rebuilt)what should i do?are the 78 rods going to work what kind of pistons should i get?what should i do with the 78 heads? all i want is a 12 second street beast thats somewhat reliable i,m probably forgetting other items that i have, sorry for the long post but i need all the help i can get, this is my first build and im kinda nervous,thanks

[rocketman]

i would use the ls-5 block,by a eagle kit(crank,rods,piston,forged) and build 468,I would either port the 78 heads,or sell the 427 heads and buy some decent 454 heads (dart,bodix,etc)

I would run 10.5 or 11.1comp a nice roller,good ported heads,that should be close to 12's if not buy a nos plate and spray it.

Or bore and stroke it to a 509 with good parts.

[astroracer]

It sounds like you picked up the LS5 block used? If you did, the first thing I would do is get it to a machine shop to be checked over. Have them mic everything to see what you've got. You will need to know bore size and journal size before you can order a kit anyway. I would also put in new cam bearings just to be safe. Cheap insurance.
If you want something that has some top end balls but won't kill lowend torque look into Edelbrocks RPM kits. Best bang for the buck in a matched system that doesn't require a ton of research just to leave you wondering if you bought the right combo.
Mark