Josh-'04 GTO

Well...for once I'm actually working on something besides my 'bird! I'm converting the 355 in my full size '85 blazer from carb to TPI. I have the computer and wiring harness from an '85 IROC and the base, runners, and throttle body off an '87 IROC. One of the questions I have is what do I need to do to make the fuel pressure correct...obviously the mechanical fuel pump is a goner. Can I use an inline or do I need to drop the fuel tank and install an intank pump? What about the distributor...what years will work with the '85 computer? Thanks!

91RS5speed

You going to have to swap the fuel pump And run new lines. You will need a sending and return line.

Any distributer from 85-92 tbi or tpi will work. You might have to swap the connector on the harness.

Kevin91Z

You can use the carb fuel feed line as the fuel-injected return line. Just run a new feed line.

The 85 setup is the weakest of the bunch, but it'll work. A better idea is to use the 86-89 or 90-92 TPI computer setup.

CASPER97TA

1 question... why? you will get more HP from the carbed setup than the TPI. you should get a new intake manifold,and bigger carb and that will get you more HP than a TPI. Ive converted TPI camaros to carbs and it wakes them up like a night and day difference. just a thought



doug

irocz383

carbs tend to make more power but waste more gas.
Fuel injected cars tend to have better torque numbers.

IMHO, if yoiu take a well tuned carb and EFI they should be about the same. Just the carb will be a little more pricey in hte fuel department.

Josh-'04 GTO

Casper- I live in Massachusetts, which gives an Edelbrock carb virtually no chance in hell of passing emissions. By the way...TPI will produce way more torque than any carb setup...perfect for a truck ( to tow my 'bird! ).

91RS-I mentioned in my original post that I needed a different fuel pump...but you didn't mention if I can run an inline or if I need an intank.

91RS5speed

Well you could get away with an inline. Your still going to have to run atleast one line. The intank would be better I think. You might have problems with the pickup in the tank. Im not sure cause I havnt done it before. Ive been thinking about putting the tbi settup in my 66 but not sure what ill doing about the tank in that. I wouldnt recoment running pressure threw a rubbler hose though. Thats why I said you should run 2 lines.

90rocz

Carbs are one of the simplest yet most misunderstood parts on cars. A well set up carb can make substantial power and get good gas milage, but you're going to have to modify it more than just "replacing the main jets". Holleys are the most tunable ones out there, with their power valves, pump-cams, secondary springs, etc etc... A correctly sized vacuum secondary Holley(cfm=2xc.i.d.or 2cfm/c.i...usually..) can be an outstanding performer on the street when matched with the right intake.
There are more books on them than any other induction, and will require a little knowledge and understanding to tune.
Big torque can be made by carbs too, it's more a function of the intake+cam+heads, than the carb itself.


Anyways, for the Ques:TPI's do make good torque for trucks!
As said you will need a ;
,,high pressure fuel pump,(in tank or in line on frame rail which I'd locate close to the fuse block under the driver.)
,,a high pressure inline filter
,,a fuel return line, which will probably require a different in-tank sending unit with an extra "hose outlet/inlet"for the return line.(used TBI truck one)
(if a pump is put in the tank it needs to be made sure it's down close to the bottom to keep fuel on it, to cool it and prevent cavitation.(sucking air)

Zepher

I am using a Holley 255lph in-line pump on my car.
I had carb and my setup had a feed and return line on the car already.

I also converted the 87 MAF setup to a 91 MAP setup so that I could run an SLP Dual Cold Air Intake setup.
Here are a couple of before and after pictures,
http://www.transamws6.com/pics/transam/Edelbrock.jpg

http://www.transamws6.com/pics/transam/engine.jpg

Josh-'04 GTO

Zepher- That was the info I was looking for! What did you do for fuel line from the carb fuel pump point to the fuel rails?

Zepher

I cut the metal lines right before the bellhousing on the tranny and ran hi-pressure rubber lines to the front of the engine bay on the drivers side to the TPI fuel lines. Originally, the fuel lines went over the tranny to the pass side and to the mech pump on the block.

The Holley Pump was mounted onto the back side of the rear drivers side seat. Here is where I put the pump

If you look at this picture, right after the tranny crossmember, the stock metal lines jumped over the tranny to the pass side. I cut the lines before it went over and ran rubber ones to the front of the engine bay up along the frame of the car.

At the bottom of this picture, you can see where the rubber lines attached to the TPI Fuel Lines

Josh-'04 GTO

Zepher....you da man! Pictures are always nice!

Now when my Formula chews up another 4L60E at the track I can tow it home

Zepher

Thanks dude,
just doing my best to help others out.