TPI Swap VS. Vortec / Carb

[WB72]

I am thinking about getting a TPI unit from a wrecker. I have a few questions for those of you who have done this conversion.

1) Will the in cab fuel tank accept a return line?
2) Is there an aftermarket fuel pump that will fit in the exhisting tank (in cab)?
3) What shall I get from the wrecker? Intake, Computer and wiring. am I forgetting something?
4) Where do they hide the computers in Camaro's? Corvettes?
5) Can I have an aftermarket cam ?

My engine is stock and I want it to have a bit of power and I will be needing to change my intake and carb anyway. Would this be a foolish swap? I will NOT be driving this every day. but I hve seen the swap in a Magazine and it is more appealing than having a hard to tune High lift cam engine.


6) What kind of power cam be expected out of this Stock TPI unit compared to a stock 350 from 1972?

[Warrens69GMC]

From 1972 standpoint, you may gain fuel economy and some torque (to 4500 rpm). Some of the guys around here prefer the TBI setup to TPI. more adjustability and more forgiving.
warrens69gmc

[Bowtie67]

I don't rremember any TPI setups on any trucks unless it is really late model. I have the Holley Stealthram in my 67 and using the in cab fueltank. You need a 3/8 fuel line to the injection system, most of these trucks had 5/16 fuel lines. My sending unit was toast and I ordered a new sending unit with the 3/8 line. On the return line I don't know if the later models with emission deals had a return or not. Not a big deal if they didn't. You can take a 5/16 or 3/8 steal line and drill a hole through the sending unit and use a butane torch and solder and install it in the sending unit. On the floor of the truck there is a single rubber that the original line went through, I removed this and took a peice of 3/16 flat peice of steel and drilled 2 holes in it and welded the two lines through it and then sealed and bolted it to the floor. TPI setups are good for about 5200RPM not 4500rpm, this is a cam issue. There is about another 15HP using the TPI versus TBI. As far as the inline fuel pump there are some companies that make some intank ones but you may have a problem getting it in the tank, I run mine on the outside of the passenger side frame. I have run single four barrel, duel Quads, early Holley FI Projection , Holley MPFI and now the Holley Stealthram all n this same truck. The FI has always run far better and gas milage has increased as well. With the original 327 and 4speed, 3.73gears and carb I averaged around 15MPG, duel quads dropped to 13mpg, Installing a 350, 700r4 w/2200 stall, Holley MPFI I got as high as 21+MPG, my new setup I will probally see a drop, 4.10gears, same 700R4 and a 413ci SBC and the truck is about 300lbs lighter. I hope to fire the new engine this weekend, headers are due in tomorow.

[djracer]

Injection is nice but much more expensive than vortec heads and a good carb! I am running vortec heads and a polished (imitation) Air gap intake with a 650 double pumper. I can't keep my foot out of it long enough to check mileage. I have a mild flat top motor with a zz4 cam and 1.6 ratio rockers and my best times are 8.56 1/8 and 13.55 1/4 with 3.73's and a turbo 350!

[72C203503ONTHETREE]

If you can afford it, go with an aftermarket TPI or similar set up. It will be at least $2,000 but will include everything you need plus a programmable computer to change stuff in case you get a bigger cam, headers, etc.. Also, make sure the TPI you get if its stock is from a 85-86 engine, the 87 up heads use center bolt valvecovers and have different intake surfaces on the heads, wont work on a older engine. The aftermarket units also have better flowing runners or intake. If you use a stock TPI you should use the cam or a new one with similar specs, unless you have a custom chip burned for it which isnt cheap. I would go with the Vortec head kit over a TPI(stock at least) anyday for much less money. Go to Pace chevy in Ohio, I got the kit for $700, but may be a little higher now. You get assembled heads, rockers, pushrods, all gaskets, head bolt kit, intake(either performer or performer RPM), and maybe some other small stuff. You will need to buy a carb and valve covers. All your accessories and small parts will swap over to the new intake and heads perfectly. I have this on my 83 El Camino and it was great, excellent throttle response and that was with a 750 carb and a fairly decent cam(lopey idle). You can't go more than .480 lift on the Vortecs with the stock springs by the way. Oh yeah, dont forget to get the TPI distributor from the donor engine. The computer in the F bodies is behind the passenger side kickpanel, not sure on the Vettes. I'm not sure but you may need to lengthen wires to put it on your truck. The only real advantage to TPI is cold weather start up and you probably will get better mileage. Power wise, a carb will beat it for a lot less expense and work. If something goes wrong with a carb theres not much to look for or fix, with any fuel injection it could be sensors, injectors, computer, etc. that may be going bad, not a big deal if youre familiar with the system but a pain if you are lacking in injection knowledge.