L98Justin

well guys i'm going to carb my 85, please i know most people wont like it but its my car..

what intake manifold did you use and what carb fits under the Hood i dont wanna modify the hood, also any help with a distributor part # and fuel pump will be much appreciated

also my 85 has the ZF6 in it would i encounter a problems there my car is a electrical nightmare at this point and im a little fed up

Deakins

It's been a long time since I did this but I don't remember too many issues with electrical. You don't need to different fuel pump as you can get a bypass regulator and set the pressure down to where you need it. I think the one I did have a run of the mil dual plane on it and everything fit up fine. As long as you don't get too tall you should have plenty of room. Just my .02

L98Justin

thanks for the reply i was starting to get nervous, no im dropping my TPI cause its a electrical nightmare, and ive been looking into a holley 600 and im just having a hard time finding a lower intake manifold that fits under the stock hood, shucks do you remeber the brand of the manifold id like to go edelbrock but havent had much success

cv67

Performer or performer EPS should fit fine
Weiand makes a very nice one also. Airstrike?!

MJFuss

Check out the Weiand Street Warrior 8120. It's a little more modern in design than the Edelbrock Performer, and it's the same height, basically, but, because it's already a square-bore manifold you won't have to use an adapter with a square-bore Holley.

It's cheap too.

L98Justin

Fuss thank you very much i really appreciate your help, i apologize for my ignorance on carb setups.. does it matter what holley carb i use?


also what is this fuel line fitting that reduces the fuel pressure??

Black89Z51

I did mine, but I can't help much in the way of an intake since I have a cowl hood.

I used an '84 pump in conjunction with a return style fuel pressure regulator.

As far as a carb, just a Holley 650 cfm with elec. choke will be fine.

My distributor is a MSD Billet run by an MSD Blaster 2 coil and a MSD 6AL box.

MJFuss

I think just about any Holley will fit with a drop-base air filter, but I'd advise using a new (or rebuilt) Street Avenger 670 cfm with vacuum secondaries. It will run pretty well right out of the box, and it will provide good performance. You'll probably want one with electric choke as well.

You'll want an in-line fuel pressure regulator (that's actually what it's called), but be sure it's the kind that uses a return line. It essentially bleeds off the correct amount of fuel pressure by sending the appropriate amount back to the gas tank. Your car is already set up for this kind of system. You'll want to have an in-line fuel pressure gauge between the regulator and the carburetor so that you can adjust the pressure to the correct level. None of this is hard to do, or expensive, just google some of the part names and read up a little bit.

You'll also need an HEI distributor to replace the stock unit. It's not hard to install or get set up with the right timing, but do some reading about it before you start.

You can also find a throttle cable mount that bolts right up to the carb and manifold, and it will work just fine with your stock cable.

There are lots of people who've put carbs on C4s, and some with very good success. Just search around on the internet and you'll find lots of good info.

If you're unfamiliar with carburetors you might want to check out David Vizard's book on tuning Holley carburetors. It's well written, and he is authoritative on the subject. It's also an easy read.

Good luck with your conversion.

L98Justin

you sir are the man i really appreciate all the help guys hopefully i can get my vette running by the end of the month thanks to you guys

project C4

Be aware... I just tried a Mallory 4309 pressure regulator on my 86 with the TPI pump still in the tank and it would not work. If you use an in tank pump and regulator make sure you switch to an 84 pump first.

I ended up taking my pump out of my tank and running a regular external electric fuel pump

project C4

I think some people have had success with a much more expensive Aeromotive regulator in conjunction with the TPI in tank pump.

cv67

Fuss youre right I got the wrong weiand name. Imo worlds better than the performer.

x2 on running the returnon the FP so it isnt heating the fuel up

Jay7199

Performer and a holley.. need a low profile carb hat

Deakins

What issues did you run into with the fuel pump in your set up with the Mallory Regulator? I ran a Mallory regulator on the 88 that I converted years back and had zero fuel issues.

project C4

Man... that was a hell of a thing. I plumbed it in right where the EFI fuel filter used to be. 3/8 line from the tank 5/16 return line and 3/8 to the Carb or Pressure gauge. The inlet and outlet on the regulator is a common port so it really doesn't matter.
Turned the pump on and checked the pressure. Rock solid 4psi. I thought, OK that's cool now I just need to get under the car and loosen the jam nut and adjust to 6psi. When I started to raise the pressure it when up to 4.5 psi and then the needle on the pressure gauge started fluctuating violently and you could feel the regulator clicking almost like a relay. When it was fluctuating it was topping out my 10psi Gauge. I messed with it for almost half the day trying different things and finally gave up. One of the things I tried was a 3/8 return line running straight out of the bottom of the regulator thinking the 5/16 wasn't big enough. didn't change a thing.

Black89Z51

I'm using a standard Holley Return style regulator if that helps any. Set at 7 psi.

Deakins

That is pretty strange! I mounted that exact same Mallory regulator up in the engine compartment and never had any of those symptoms. Hopefully they didn't change the design over the years as that was a very good regulator for us (it's now running in my C3).

project C4

Tell me ! I used this jegs regulator on my s10 three years ago ,plumbed in the exact same way, and I have not touched it since. Granted the s10 in tank pump is a lower pressure TBI pump for a 2.5 4 cyl
http://www.jegs.com/i/JEGS-Performan...oductId=773419
the Mallory comes highly recommend and I thought it might be a step up from the jegs unit.
The more I dug around on the web the day this was all happening I DID find other people having similar problems with the 4309 reg.

project C4

Also... I took the Mallory regulator apart and sure didn't see anything wrong. The diaphragm was perfect. doesn't mean the reg. wasn't bad just nothing that I could see.

maybe there is a difference in the in tank pump that causes some people to have problems and some not. My car still "had" the factory pump in it.

383vett

What psi range is the Mallory rated at? Maybe it's not able to lower a 45psi input pressure to your required 7psi. Just a thought.