I plan to swap the 305 out for a 350 for my Formula. The car came with TBI and I'm giving serious consideration on switching to TPI. The engine I'm considering is the GMPP 330hp 350 HO with Vortec heads. I've been told that TBI can feed this motor adequately with proper tuning,but I've also wanted to upgrade to TPI as well. Street and Performance makes a kit that allows the upgrade to TPI while still keeping the majority of the stock electronics in tact. This involves a special harness and piggyback type of unit that works in conjunction with the stock ecm. What do you folks think? Is it worth it? Should I just keep it simple and stick with TBI or take the plunge and step up to TPI? Anyone here who has done the swap chime in as well.

 

If it were me... I'd ditch the TBI and go carb'd. No computers involved... much simpler, less down time, more go.

TPI as much as it would be an upgrade to TBI, it still has it's obvious downfalls. If you must go w/ fuel injection though, look for an LT1 intake, or SuperRam, or MiniRam. Get a TPI wiring harness, wire it all up, burn a chip for yourself (go to the PROM burning boards), then tune it, tune it, tune it, tune it, until yah die

 

I would have to second that, the TPI swap will be alot more expensive and time consuming. With the carb, its alot easier to tune and in my opinion will make more power. Im getting ready to make the swap myself on my 305. If you want i will let you know how it turns out.

 

Thanks for the opinions guys. The problem with going carb is that even though emissions testing will be terminated in NC for cars 1996 and older after 2006 the equipment will still have to be intact on the vehicle to pass. Plus I'll have to admit I think a TPI just looks cool. And the fact that I've always been an FI fan is going to keep me with one of these two. I've also done some more research on the S&P kit and it doesn't seem like a very hard swap. The hardest part of it is swapping out the fuel pumps while the rest is done underhood. Let me know how the carb swap turns out.

 

You can make more power for less money with a 350 TBI than with the stock TPI set-up. I would only go TPI if you replace it with a stealth ram, super ram, miniram ect ect.

 

Well to be honest,the TPI wouldn't be very stock when it's finished. I'd have to use a Vortec TPI base for the heads and I'd be using at least a 52mm TB. Not sure about which runners I would use just yet,either long tube or siamesed at this point. I've also been thinking about how the hotcam would work with this motor as well. I'm also leaning very hard on using long tube headers as well. Not to mention plenty of dyno tuning to get it dialed in. The only thing that's for certain right now is that there will be a 350 of some sort under the hood.

 

You can hit low 13's/high 12's with the stock tpi, you just need some decent heads and a cam. Switch to tpi.