19EIGHTY5CAMARO

Im converting my 85 z-28 to a carb. from tpi. i was wondering what all would i be looking at to change? I know i will have to change the heads, add an intake, change the dist. and ign. I was really wondering if there are any other major things i will have to change.??? i would appreciate any help..!! thanks.

Pneumatic_Tire

Why would you want to do this? I hope you got good mods in store, cause you are goona loose some serious power. Basically, you should just need a carb intake, a air cleaner, a vacuum advance distributor, and a different fuel pump setup. 40+ psi will not work on a carb. They only run on like 4-7 psi or so. Wait for someone else to chime in that has more expierence with doing this.

greezemonkey

Tire is right! intake, carb, dist, pull the ecm harness..it`s completely seperate in you car heads will be fine leave `em.
You can keep the pump in the tank if you want, Mallory makes a 4 port regulator that will bring the pressure in line and still use the return line, it`s close to a hundred tho . you`ll need to power your fuel pump up from the key too. Your electric fan will also need a stand alone system to turn on and off...hayden has an a kit for around twenty five that turns on at 190* and off at 170*...I`ve used mine to run 2 fans for the last 7 or 8 yrs My experince was I changed over to a carb when the wennie runners were holding the engine back(350 .60 over w11.1 280/290 hyd roller+world 200 heads) , back then cheap FI alternatives were not avaliable, anyway the difference from FI to carb was night and day for all out power

Rice Killer87

what are u talking about dude? even if u kept the stock heads,ill bet the carbed car would pull that TPI car,b/c the TPI is basically junk after abuot 5000 RPM's or so and that carb will pull to 5500+ depending on what intake u buy.

ive done the swap and just left the wiring harness in the car,incase me down the road,or some1 that buys it from me ever wants to put F.I. back on it down the road. that way the compu stays in the car and u dont need to re-wire the fuel pump.

u need a HEI ign. distributor (i dont even use the vacuum advance on my car),intake,carb,and if u have the money,i would throw some heads on there while u have it all apart...Vortec's are a great street head for the money. u will also need a way for the torque converter lock up.

i used the Mallory fuel pressure regulator on my car,took the fuel pressure down to 5 psi and uses the factory return line,and 1 of the extra ports i put a fuel pressure guage in.

Zepher

TPI to carb is a walk in the park. Personally, I think a stock TPI is a piece of ****, but it does look really cool.

If it were my car, I'd pull the intank pump, place a rubber line in it's place, get an external electric pump for a carb, run some braided lines from the fuel rails on the body to the carb and on the regulator.

Here are 2 pics of my setups,
TPI,


Carb,

Dragula85Z28

I did the tpi to carb on my 85 some years back and it was pretty much cake except all the wiring looking like crap afterwards.

everyone's reply is right the only thing i can think of that was left out is

1) i had to get a bracket from holly to fix the geometry of the kickdown cable for the 700r4.

2) had to get a lock up converter switch.

3) you'll have to get a different throttle cable casue the one for the tpi is way to long.

RedIrocZ-28

Rice killer, whats your car run?

Pneumatic_Tire

"what are u talking about dude? even if u kept the stock heads,ill bet the carbed car would pull that TPI car,b/c the TPI is basically junk after abuot 5000 RPM's or so and that carb will pull to 5500+ depending on what intake u buy."

Ok, first of all we need to find out what he wants this car for. Street, or strip? If it's street, then you should not even be running a 305 or 350 past 5 grand on a regular basis, unless you are asking to throw a rod. If he wants to make this a strip car, then yeah, switch it to carb, but upgrade the crank, and put 4 bolt mains in, or it won't last very many runs. And the TPI has alot more low end torque than a carbed 305, or 350 stock. It runs outta steam cause the 350 and 305 arn't meant to pull past 45grand or so.

Rice Killer87

y cant u run a motor past 5 grand on the street??

"ungrade the crank,and put 4 bolt mains in.." why? maybe he doesnt have the money to do that yet. u dont need to upgrade the crank just to pull over 5000 RPM's. a 4 bolt main wont really make a difference untill 400-450 HP from what i know.

"and the TPI has alot mroe low end torque than a carbed 305 or 350 stock" no kidding,but the torque isnt gonna be there to help u at 4500+ RPM's in that JUNK TPI intake. remember pal,when ur tryin to go fast....torque GETS u there...horsepower KEEPS u there..

"it runs outta steam cause the 350 and 305 arnt meant to pull past 4500 or so" no....the TPI intake WONT LET IT PULL PAST THAT b/c of the long intake runner design,thats y the TPI has alot of torque (b/c of the long runners),it has nothing to do w/ the engine itself,its the intake design.

o yea,did i mention that the TPI is junk?

Damon

I'm doing a similar (not identical) TBI-to-carb swap right now on my wife's 1992 Camaro. Shoot me an email and I'll give you all the gory details, if you like.

The basic nuts-n-bolts of it aren't too tough but the throttle/trans cables will drive you nuts, and the fuel system needs to be addressed, plus some relatively straight-forward wiring changes.

Highlights....

Mallory high flow bypass-style regulator needs to be patched in to get fuel pressure down to a carb-friendly ~6PSI.

Gotta replace the computer controlled distributor with a non-computer controlled one. If your car already uses a large-cap HEI with the coil in the cap the stock power/tach wiring will plug right in to an earlier non-computer controlled large cap HEI, minus the computer controlled timing connector, obviously. If you've got a small cap HEI with a separate coil you need to modify the wiring to work with an earlier non-computer controlled large cap HEI.

Gotta get different throttle and trans cables than your TPI uses (get cables for a 1984 carbureted LG-4 3rd gen) plus an appropriate bracket (Holley) that will keep them in correct orientation to the carb's throttle arm. If you're using a typical Holley carb this is pretty simpl;e- if you know how (I'm using a Holley on my engine- other carbs may require slightly different setups). I've spent the past week getting this worked out on my car and I think I've covered a lot of ground in a short time on this issue. You'll pull your hair out on this seemingly simple issue unless you know what to do.

Pneumatic_Tire

Rice Killer, you make some good points, but you need to calm down a little.

82355

Maybe, but pneumatic_tire you shouldn't chime in if you don't know what your talking about. Can't take a street engine past 5000 RPM, are you serious??? Need 4 bolt mains to do so, wow, you need a little real life experience before you go scaring people with false info.

Martin

Pneumatic_Tire

Wow, ok, so you are gonna tell me that gm redlines the 305 and 350 at 5 grand for the nothing? I admit, I may not know it all, but I do know if you want to safely run that engine with no worries beyond it's factory redline, it needs some upgrades. Also, if you read the wole post, you will see I specifically said for him to wait until someone with more expereince chims in.

82355

They redline them there because that is where they quitr making power. Do some work to them so they can pull over 5000 Rpm and they will take the abuse all day long. You specifically said running a 305 or 350 past 5000 RPM on a regualr basis you will throw a rod. Trust me, I have blown up lots of engines and I have winged a lot of engines past 5000 RPM. If you want examples just ask.

Martin

Pneumatic_Tire

"You specifically said running a 305 or 350 past 5000 RPM on a regualr basis you will throw a rod."

Once again, you must have misread my post, I said you "risk" throwing a rod.