TPI w Vortec Head Conversion ?!?!? Possible???

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,017
Reaction score
9,019
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
So if a guy wanted to cheap out and just go old school TPI without the Vortec heads and the need for a Dick and ******* intake then what kind of hp/tq can be expected with an OEM TPI 350?

Does this ODBll set up with MAF and Crank Sensor add any hp/tq?
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,146
Reaction score
24,097
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
So if a guy wanted to cheap out and just go old school TPI without the Vortec heads and the need for a Dick and ******* intake then what kind of hp/tq can be expected with an OEM TPI 350?

Does this ODBll set up with MAF and Crank Sensor add any hp/tq?

Stock 350 was around 240hp/300tq, give or take a little depending on the year. The 350 TPI I built for my Camaro will run circles around a stock car and it really didn't take much to get it there. Still stock intake, runners, and TB too.
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
133
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
So if a guy wanted to cheap out and just go old school TPI without the Vortec heads and the need for a Dick and ******* intake then what kind of hp/tq can be expected with an OEM TPI 350?

Does this ODBll set up with MAF and Crank Sensor add any hp/tq?

Mine was 237hp 406 ft lbs, but I never completed the tune.
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,017
Reaction score
9,019
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
Mine was 237hp 406 ft lbs, but I never completed the tune.

That's alot of torque for a basically stock small block. Sounds like it would make a good 4x4 motor without having to spend the big bucks. I'd even considered just going TBI. Not looking for a drag race motor, just something good, durable, dependable with a bit of pull power that won't starve for fuel on steep inclines. You can only go so fast on wheeling trails, bad weather roads and mud holes. It's not going to be for competition. I'd rather cheap out on the motor and go with middle of the road, and put the funds into traction assistance, ie Lockers, Gears, Tires, Suspension etc..
 

RetroC10Sport

Supporting Member
Supporting Member
Joined
Sep 29, 2010
Posts
17,092
Reaction score
2,213
Location
Green Bastard Parts Unknown
First Name
Jay
Truck Year
2001
Truck Model
pontiac aztek
Engine Size
3.4
You must be registered for see images

You must be registered for see images
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
133
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
You would have to work a TBI pretty hard to get there. The engine really benefits from the multiport injectors spraying directly onto the hot intake valve, and the long runners.
TBI also has some fuel distribution issues, like carbs.
You also want to stick with a cam that has low duration...but lift can certainly help. Open and shut fast, but try to cram as much as possible in. I saw somwhere that a guy used a stock cam, but stuck some 1.6 roller rockers on, and picked up 10 hp, and 26 ft lbs
 
Last edited:

Green79Scottsdale

Full Access Member
Joined
Aug 8, 2010
Posts
2,834
Reaction score
7,483
Location
G.R. - MI
First Name
Bob
Truck Year
1979
Truck Model
K20
Engine Size
400
Damn you guys and your TPI talk!! I have wanted to do TPI on the 400 in my '79 ever since I had a Corvette with a breathed on TPI 350. The torque in that thing was awesome! Yeah I noticed the "wall" that the stock stuff runs into, but it didn't bother me cause I am not a big mph guy. The only problem I ever had with it is the stupid thing would never idle right. No matter what I did I could not get it to idle around 8-900 rpm like I wanted. If it would get below about 750 rpm it would stall. It needed a good tune, but being OBD1 it was difficult because no one around here deals with that anymore, and it was never worth the hassle of sending all the info off to have someone in another area help me. So to hear you can adapt it to OBD2 with it's easier tuning capabilities is awesome to hear.

Jim is there a resource where I can read about adapting OBD2 to TPI, so I don't have to take up all your time? I know next to nothing about this kind of stuff, and I don't visit my Corvette Forum anymore.

And I had my mind made up to keep my truck basically stock..... :angry94:
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
133
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
Its pretty straight forward.
If you have a TPI already, just envision removing the harness and ecm, distributor, and replacing it with a 96 truck harness, only, you will be splicing the old injector plugs to it, as well as the old IAC plug, and maybe the TPS plug.
Dont forget the MAF sensor, and the IAT sensor. Parts ar available to build a custom intake tube to accomodate those items.
Installing the vortec ignition....dist, ICM, coil, and timing cover with crank sensor, and reluctor ring on the crank.
Thats it. The only tuning that would really need to be done, is to shut off the trouble code for the aft o2 sensors, which just tell you if your cat is not working, and the egr code if not using EGR.
If you still want EGr, there is a way to do it both in vortec, and non vortec cases. But you need to use the vortec EGr valve mounted externally and with Manifold mods, because it wont fit under the TPI plenum.
OLP will chime in if I am missing something.

Oh yeah, if you really want get jiggy wit it, there is a kit to use an LS system on your sbc TPI, using the distributorless coil system.
 
Last edited:

8T6K5

Full Access Member
Joined
Jun 22, 2012
Posts
1,128
Reaction score
112
Location
AZ
First Name
Jerry
Truck Year
1986
Truck Model
K5
Engine Size
L98 350 TPI
Way too hi-tech for me. Im having a hell of a time just figuring mine out. Spent the better part to today untangeling the Charlie Foxtrot mess to wires inside the engine bay. Basically undid most of the loom, seperated and re-routed a few of the leads....

Before:

You must be registered for see images attach


You must be registered for see images attach


After:

You must be registered for see images attach


May seem counter productive to my goal, but after a lot of reading I decided to scrap the A.I.R system:

You must be registered for see images attach


Will replace the pump with an idler pulley:

You must be registered for see images attach


You must be registered for see images attach


Teaser pics...

You must be registered for see images attach


You must be registered for see images attach
 

Latest posts

Forum statistics

Threads
42,206
Posts
911,332
Members
33,703
Latest member
ChevyJGP
Top