TPI Fuel Components

There are two different tpi fuel rail plumbing locations. The f-bodies exit on the left side, the Corvette's exit on the right. Depending on this location will determine how to fabricate the lines to feed fuel to the injectors. In my case where the fuel lines are on the left side I had to use fuel lines from a RWD TBI car such as 4.3V6  or V8 TBI Caprice, Monte Carlo, and by using a tubing bender, modified the lines to travel between the water pump and timing chain cover, down across the lower right front of the engine. Then you can use the GM fuel injection lines or aftermarket fuel injection lines that are similar and using appropriate connections to make the complete fuel circuit. Just be sure to use new "o" rings so you wont have a leak.   What I did was to cut several ends from several TBI cars and used tubing connectors to get the exact set up I needed. 

Bosch injectors were used up until the 1987 model year on most applications, Multec manufactured by Rochester products were a vast improvement, they will interchange on earlier years. Another type (not pictured) is the Bosch type injector with a extended "chimney" to aid in anti-fouling.


Picture above is a typical f-body complete tpi fuel rail, for 1985-1988 with cold start injector

The Corvette injector rail above has the fuel line plumbing on the passenger side


Fuel Rail ID Chart

Fuel Rail ID Chart 5.0L engines:


17085052 F 1985-87 5.0 Bosch
17087204 1985-87 5.0 Multec
17089024 F 1989 5.0 Rochester
17090100 F 1990-91 5.0 Rochester

Fuel Rail ID Chart  5.7L engines:

17085050 Y 1985 5.7 Bosch
17085019 F,Y 1986-87 5.7 Bosch
17086106 F,Y 1986-87 5.7 Bosch
17087265 F,Y 1987-88 5.7 Multec
17087266 F,Y 1987 5.7 Multec
17088065 F,Y 1988 5.7 Multec
17089025 F,Y 1989 5.7 Rochester
17089026 F,Y 1990 5.7 Rochester
17080101 F,Y 1990-91 5.7 Rochester
17080102 F,Y  1990-91 5.7 Rochester

LINK FOR CALCULATING INJECTOR  FLOW RATES (especially for above stock/modified engines)


First picture shows location of front fuel lines. These were fabricated from fuel lines from a rear wheel drive TBI. Be sure to bend them carefully with a quality bender or you'll end up trashing the lines by kinking them.

 Be sure they clear the back of the water pump without rubbing, or you can use a split rubber hose wrapped on the lines to prevent chaffing.


 Second picture shows the fittings I used in making the connections to the flexible lines. (A) 3/8" return line (B) 3/8" supply line (C) 3/8" pipe to 3/8" tube fitting. (D) 3/8" to 5/16"  reducing coupler (E) 5/16" pipe to 5/16" tube fitting (F) 5/16" fuel line fitting from a GM TBI car to connect to 5/16" return fuel line (G) 5/16" flexible return fuel line. (H) 3/8" flexible supply fuel line. (I) 3/8" fuel line fitting from a GM tbi car (J) 3/8" to 3'8" pipe coupling.    

The picture above shows the fuel lines routed just behind the A/C compressor, then take a 90 degree bend to meet the rubber fuel lines.

The fuel lines must clear the fuel lines, use a fabricated heat shield made of then steel plate at least 14 gauge for added safety. This is important! Bolt it to the hole in the side of the serpentine belt bracket. If using a V-belt arrangement, you will need to mount it to another hole on the block.

Clamp the lines to secure them, this may take some ingenuity.


Another option to run your fuel lines involves using the steel braided lines that were found on some of the 1988 and later fuel size trucks equipped with the 305 or 350 TBI engines. One good thing about the flexible lines that they are more easily adaptable to route your fuel lines and the bonus is that there are fewer connections to make and that reduces the likelihood of leaks. 

This is the set of fuel lines you'll need. They are the 5/16" and 3/8" lines which will hook up to the TPI fuel rail with no problems. The outside line is the 3/8" which has the male end fittings. The inside line has a 5/16" female fitting requiring a piece of steel fuel line with the male fitting. Notice the right side of the line with the 5/16" male fitting that goes into the fuel rail. It has a short 3 inch length of hard line which normally is factory bent in a 110 degree angle. It has been carefully straighten to be usable for our modification.


This picture shows the fuel lines in a mock up, with the accessory bracket it place to check for clearance. The red arrow shows the straighten fuel line that just clears the fuel pump. If you ever have to replace the water pump for any reason, you will need to remove the 5/16" line to access the bolt. As you can tell, the line isn't perfectly straight, which is okay. The main thing to remember is not to get in a hurry, not to kink the line, otherwise you will trash it. Putting the fitting end in a vice and using a outward pulling motion with the line facing you, you can straighten it.  The blue arrow show the lines going between the water pump and bracket. You will need to file back about a 1/4- 3/8" in this spot  to allow for some movement.


With the power steering pump in place, the fuel lines clear with no problem. When the lines are routed just under the front of the oil pan, it is recommended to secure the line with clamps to the frame. Do not allow the lines to dangle or otherwise come in contact with the harmonic balancer or any moving steering/suspension parts.


The lines are routed on the passenger side rail in my Camaro. Since I had the engine out for my 383 stroker upgrade, I decided to change the fuel line set up. The red arrow shows the fuel lines being routed under the brake line and barely seen in the picture is a dual line clamp to secure the lines. The blue arrow show the line fitting adapter. You will need some ingenuity here to get the lines adapted. the one thing here is to remember to get all the fittings tight.



The third picture shows the two lines running along the frame, such as a second generation f-body. The second fuel line also came from a 2nd gen. Camaro. Note that I marked the supply line with red tape, the return line with white tape. Do this so you can avoid confusion of which line is which. Also high pressure fuel injection hose is used and doubled clamped for safety.

Back towards the tank, route your fuel lines with as few bends as possible, away from any close proximity to exhaust pipe, use the flexible high pressure fuel lines and fittings to allow for movement and ease of routing.   

UPDATE:  I was going to use the Caprice fuel tank with stock in-tank pump location. When I got ready to run my exhaust pipes I found there was very little clearance for safety reasons between the tank and the pipe. In fact, the routing of the exhaust would put it between the tank strap and tank itself. I had to scramble to find a stock Camaro tank ( since I had already tossed my original one) and then installed a externally mounted pump. The exhaust pipe now clearly has plenty of room, as originally intended. Be sure to allow a minimum of 3 inches or more of clearance between your tank, fuel line and hoses.  SAFETY FIRST!!

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