Lowaholic

ok, all- here's the deal. I'm happy cruising along, stockpiling parts for my future TBI 350 (L05) rebuild, but still occasionally thinking out loud about 'how sweet it would be to have a TPI under the hood'. So my gf apparently takes me literally and tracks down a TPI setup and gives it to me for my birthday. So... the question is:
Do I change plans and go with the TPI swap? I've compiled a list of pros & cons from what I know and what I've heard, feel free to throw comment/ideas and correct me where I'm wrong here:
PROS:
- I already have a set of vortec heads and was planning on getting the GM TBI base, so $$-wise I could just get the SDPC base instead.
- The engine in question is in my AWD S-10 Blazer not the Camaro, so I'm figuring the low end from the TPI might be nice...?
- The engine is a factory roller cam, so a ZZ or LT cam will bolt right in
CONS:
- Even though the low end from the TPI would be nice in the truck, ideally I want a strong power band up to around 6k rpms
- Obviously cost/availability of TPI parts
- Extensive tuning necessary to make a 400+hp TPI setup, but then again, TBI would too...

have i missed anything? I'm really tempted to do the swap. I know I'm probably better off power-wise with the TBI, but the TPI just looks so much sweeter under the hood. As far as making good high RPM power, would I be best off focusing on higher-RPM mods (ie-porting/polishing heads/intake, radiusing, cam, etc)? Would I be best off with a ZZ3/ZZ4 cam or the LT4 hot cam? Any thoughts? Thanx tons in advance

Jim85IROC

iTrader: (2)

stock TBI runs out of power at even lower RPMs than TPI. If you notice, all TBI 350 trucks have a redline of 4,500 rpm. Granted the cam has a lot to do with it, but my point is, you're not going to get 6k rpm power and low rpm power out of any induction system, whether it's TPI or TBI. Decide where you want your powerband and build around it.

D Stroy H8

I think you can get 6,000rpm out of the TPI if you get good runners to go along with the SDPC base. BTW: the SDPC base flows better than stock and is portable and can be hogged out even more.

formularpm

TBI or TPI? Neither. If you cant afford a better flowing system, however, youre generally better off with port injection as opposed to a central injection system like TBI. Port injection is a lot more precise and will almost always make more power. I wouldnt consider the tuning aspect a con, either. There is power to be had in tuning. Id also recommend doing a lot of research before you consider porting Vortec heads, word is that its easy to mess up the positive flow characteristics of the casting once you start grinding. Vortecs are known for their great swirl characteristics, and those are designed into the head.