Okay, here a few questions about the L31 vortech heads I'm putting on my gf's 92 firebird 305tbi. I've done a lot of work on cars, done pretty much everything cept assemble a short block. What I don't have experience in is matching up components. I've searched quite a bit, but still have a few questions.

1) What cam are you guys running and with what kind of results? Any recommendations are also greatly appreciated.

2) How easy is it to adapt the 454tbi unit to a 305? Is there a wiring nightmare? Can it be ran without damage for a few weeks b4 ecm tuning?

3) Anyone have any experience with the gmperfomance parts intakes #12496821(vortech tbi) or #12496820(vortech 4bbl)? Possibly the 12496822(eliminator vortech), but it looks a lil extreme for street.

This is where it gets interesting. I am going to have a 3.73 or 3.42 rear end with posi installed and broken in b4 this install. I will have a new cat and catback exhaust installed prior also. I have a full mechanics bay with lift and all the goodies available for one day, with a cert ase mechanic to help with the time issue. I am planning on installing the cam, L31 heads(already milled),intake, tbi, headers and possibly an alum driveshaft all at once. I'm hoping to make this a big surprise so all the time I have is while my gf is at work, from 8am-6pm approx.

4) I personally think there is time, but a buddy is telling me no way. One of my other friends, the ase mechanic thinks it could if everything went ideal. What do you guys think?

5) The biggest issue.....can the ECM take it?!?!?!?!? Can it be driven without major issues for a week or 2? I will really need it to start, not my car after all. I am already starting to play with eproms, and will be able to do it, but I don't know how soon after the install. I know I won't be able to do it that day with the time constraint. I know to keep the egr will be an issue with the L31 heads, and I'm researching that now.

6) Am I living in a dream world? lol I know I'm optimitic, but this even seems tough to me. I know I've swapped out heads on ohv 4cyls in under 2hrs, but things are a lot more cramped and a lot bigger than the 4cyl.

7) Is there anything you guys can think of that will make me on install day?

I'll shut up now. Thanks for your advice in advance!!

 

1st. Good luck trying to pull that off in a day. My luck NEVER goes that well. It could conceivably be done in one day if your mechanic is a hell of a worker.

2. The LT1 Z28 cam is a great bang for the buck cam for the 305 engine and won't require machining the valve guides to run a bigger cam.

3. The 305's TBI unit will be fine with that setup. You will want to do the ultimate TBI mods to it but the 454 throttle body will just add to your modifications list. Start with the modded 305 TBI and go from there. Also, you will probably need the 350 injectors as well. Might as well go for the cop car injectors.

4. On the intake, again if you want to make it happen in one day go with the Vortec TBI intake. It should work just fine on a 305. If you were running a 350 then maybe a different intake but I think you will be just fine with the Vortec TBI.

5. Lastly, the ECM can take it but that chip isn't. Your going to be adding a conservative 80hp to an engine that had 170 to begin with. That's a pretty drastic change.