EFI or carb. ?

krepe · 04-21-2001, 11:43 AM

I currently have a 89'Mustang GT.I have a 83' 351 Windsor(rebuilt).Forge pistons(40 over) 24lb. Injecters,stock heads,stock throttle body(65mm. i think),3-core radiator,180 thermostat,gear to gear timing,headers,no cats,3" pipes all the way back,cam,racing clutch,K&N filter,Edelbrock Performer RPM upper/lower intake.
The computer in my car is from a 302,and since i have a 351 Windsor ppl are telling me that,that is why my car will not perform down the track,that I should be in the mid-13's.So my main ques. is.
1)Buy a computer for this engine?
2)Should I tear that EFI bullshit off my car or should i pop a carb. on it?

best 1/4 mile = 15 flat
weight of car = 3,450lbs.

thx guys, -krepe-

krepe · 04-21-2001, 11:51 AM

I also need to know,what do i have to do when going with the carb.?

I know i have to take the intake off and put a carb.intake,and carb there,change the air flow sh*t off the side there,someone said i had to change distributers,maybe the fuel pump. has anyone done this bfore?, i need help with this one if i decide to do it, its all up to the replies i get for this,pretty much a vote lol.
thx again people, -krepe-

Stampede · 04-21-2001, 12:32 PM

Krepe.
I have a few questions to ask, first what is your mph? What type of cam do you have? What type of trans do you have a t-5 or AOD? Also what type of heads, the stock E7TE heads?
Is your mass air sensor cal. for the 24lb injectors? What are your shift points ????
Also for the carb, I'm a big fan of efi. And with a carb you will lose gas mileage and increase pollutes in the air. I would first find what's wrong with this set up first. But you'll need a carb, I perfer a holley 600 cfm, some people say you will need bigger, but you don't. You'll need an intake, reroute some vac. lines. I'll have to look to see what dist. you will need, and as for the air pump, I would take that off anyways. As for the fuel pump, you will have to decrease pressure to about 6 or 7 psi, I think.
You should of been in the mid 13's with the 302.
Stampede.

shovelnose · 04-21-2001, 12:54 PM

All of what stampede said.

Carb is cheaper by far to upgrade. Plus easy to diagnose. You will need a distributor cause the one you have will be computer controlled. You need mech./vac. advances.

You need to pull the in tank pump. Way to much pressure for a carb even with a regulator.

However since you allready have the goodies for efi. I would work with it. The computer is a good idea. Have the heads been port-matched or anything. Are they stock 302 or 351 heads. Do you have an adjustable regulator and whats your pressure at. I think stock TB are 58-60mm. A little small for all that motor/intake and exhaust.

What gears/cam? Your setup would probably like to rev some. Damb that thing should be a rocket.

------------------
82 Mercury Capri 302.
Comp. Cams
Tremec 3550
3.73's
12.8@106 N/AKevin's Capri

Stampede · 04-21-2001, 01:16 PM

I also think your exhaust is a little big, 2.5 is big enough, I bet it louds great, and your computer is fine for your set up. Not a set back at all, the stock ford efi computer is great.
Stampede.

Unit 5302 · 04-21-2001, 02:19 PM

Um... am I the only one that's noticing 1983 351?

In stock form that's good for what? 160hp, maybe?

You need heads for sure.

What intake is on it? The 1983 351 wasn't SEFI, and the 302 intake won't fit onto a 351. What cam do you have?

A stock 89GT Hatch weighs 3100-3150 lbs, do you have a vert? Or is that the race weight?

The computer shouldn't be causing the problems. Is you MAF calibrated for 24lb/hr injectors??? If not that's obviously a big problem.

Here is what you should have to run a 351 on SEFI with a cam.

77mm MAF, 75mm T/B (stock is 60mm on the 89GT), adjustable FPR, 190lph fuel pump, high flow intake (TFS, Edelbrock, Holly...ect), and some good aftermarket heads. Again, TFS, Edelbrock, AFR, ect...

Sounds to me like your combo may be horribly mismatched, which is why you can't get anything out of it. I'm guessing the heads are holding you back HUGE time.

juiceman · 04-23-2001, 03:27 PM

first off, you should be able to hit high 12's with a mostly stock 351. if you use a carb you will make more power cheaper and sooner. it takes more to get power from injection. as for parts using a 600 on a 351 is ok but will choke it up top. no less than a 650 d.p. and for the dist. use a msd unit with the msd ignition for easy hook up and tuning. 351's dont rev so dont plan on reving it past 6000 much in stock form.

04-24-2001, 04:17 PM

I agree with Unit on the statement that your engine components are mismatched horribly. It's best to stick with parts that are made to work well with eachother.

On the whole carb vs. efi thing, they both have their advantages and disadvantages. EFI is way more expensive and just kind of a pain sometimes because it's all computerized and you can't do everything the old fashioned way. With a carb, pinpointing the problem is way easier than with computers.

I run a 750 Edelbrock carb with RPM intake and RPM cam, stock heads, 3:1 gears, and it bogs, but not horribly after I've learned how to control my engine a little more. And it pulls harder than crap on the top end squirting 750 cfm into the intake! If I'd get rid of my stupid a$$ stock heads and run some 3.70s I'd be mid-13s with a 3200-3300 lb., 32 year old car with a sh!tty suspension! Man...I can't wait until I get some $$$!

------------------
'69 Coupe with 351W
=========================
Edelbrock RPM intake, Edelbrock RPM cam, Edelbrock 750 cfm carb, Edelbrock lifters, Edelbrock double roller timing chain, Edelbrock valve springs, Accel coil, Moroso Blue-Max wires, Hedman headers, 2 1/2" pipe, glasspacks, Flex fan, Lakewood traction bars, C4, 3:1 open rear--9" 3.70:1 posi coming this summer
=========================

red82gt · 04-25-2001, 02:06 PM

BIG PROBLEM! the 83 351 was the epitome of the smog motor! There was no such thing as performance in the 1983 351w! It had a weak flowing set of heads, 8.2:1 compression and a camshaft with less than .400" of lift. Before you run to a carb and maybe pick up 2/10ths get a real set of heads, and an edelbrock performer RPM cam. The intake is a bigtime mismatch for the current motor, so are the 3" pipes. I'll bet that with the cam and a set of heads and no other changes you'll be deep into the 13's.

------------------
GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B+M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

Violent84 · 04-25-2001, 09:08 PM

Changing from EFI to a caeb isn't that bad. My uncle went from 4cyl to 460. It's just a little time a little money and alot of patience. I like my carb setup on my 84. I think if I had an EFI setup I would learn it and do the best to build horsepower and stay efficient. They both have benefits. I say research the topic and decide based upon personal prefference.

later,
Violent

------------------
84 GT-350, 2.5" Ram air hood, Centerline Pintails, 5-lug conversion, Recaro's, 140 speedo, 8.8 conversion, 3.73's, Motorsport A/C eliminator, Hurst shifter, ASP pulleys, Eibach pro kit, KYB's, Flowmaster exhaust, Long tubes, Custom X-pipe, Extreme Energy 268 Ported stock heads, Pete Jackson Gear drive, Weiand Xcelerator intake, 3-core radiator,and more to come!

04-21-2001, 11:43 AM	#1
krepe Registered Member Join Date: Apr 2001 Location: jupiter, FL Posts: 7	EFI or carb. ? I currently have a 89'Mustang GT.I have a 83' 351 Windsor(rebuilt).Forge pistons(40 over) 24lb. Injecters,stock heads,stock throttle body(65mm. i think),3-core radiator,180 thermostat,gear to gear timing,headers,no cats,3" pipes all the way back,cam,racing clutch,K&N filter,Edelbrock Performer RPM upper/lower intake. The computer in my car is from a 302,and since i have a 351 Windsor ppl are telling me that,that is why my car will not perform down the track,that I should be in the mid-13's.So my main ques. is. 1)Buy a computer for this engine? 2)Should I tear that EFI bullshit off my car or should i pop a carb. on it? best 1/4 mile = 15 flat weight of car = 3,450lbs. thx guys, -krepe-

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04-21-2001, 11:51 AM	#2
krepe Registered Member Join Date: Apr 2001 Location: jupiter, FL Posts: 7	I also need to know,what do i have to do when going with the carb.? I know i have to take the intake off and put a carb.intake,and carb there,change the air flow sh*t off the side there,someone said i had to change distributers,maybe the fuel pump. has anyone done this bfore?, i need help with this one if i decide to do it, its all up to the replies i get for this,pretty much a vote lol. thx again people, -krepe-

04-21-2001, 12:32 PM	#3
Stampede Registered Member Join Date: Jun 2000 Location: oh Posts: 93	Krepe. I have a few questions to ask, first what is your mph? What type of cam do you have? What type of trans do you have a t-5 or AOD? Also what type of heads, the stock E7TE heads? Is your mass air sensor cal. for the 24lb injectors? What are your shift points ???? Also for the carb, I'm a big fan of efi. And with a carb you will lose gas mileage and increase pollutes in the air. I would first find what's wrong with this set up first. But you'll need a carb, I perfer a holley 600 cfm, some people say you will need bigger, but you don't. You'll need an intake, reroute some vac. lines. I'll have to look to see what dist. you will need, and as for the air pump, I would take that off anyways. As for the fuel pump, you will have to decrease pressure to about 6 or 7 psi, I think. You should of been in the mid 13's with the 302. Stampede.

04-21-2001, 12:54 PM	#4
shovelnose Registered Member Join Date: Oct 2000 Location: Ontario, Canada Posts: 234	All of what stampede said. Carb is cheaper by far to upgrade. Plus easy to diagnose. You will need a distributor cause the one you have will be computer controlled. You need mech./vac. advances. You need to pull the in tank pump. Way to much pressure for a carb even with a regulator. However since you allready have the goodies for efi. I would work with it. The computer is a good idea. Have the heads been port-matched or anything. Are they stock 302 or 351 heads. Do you have an adjustable regulator and whats your pressure at. I think stock TB are 58-60mm. A little small for all that motor/intake and exhaust. What gears/cam? Your setup would probably like to rev some. Damb that thing should be a rocket. ------------------ 82 Mercury Capri 302. Comp. Cams Tremec 3550 3.73's 12.8@106 N/AKevin's Capri

04-21-2001, 01:16 PM	#5
Stampede Registered Member Join Date: Jun 2000 Location: oh Posts: 93	I also think your exhaust is a little big, 2.5 is big enough, I bet it louds great, and your computer is fine for your set up. Not a set back at all, the stock ford efi computer is great. Stampede.

04-21-2001, 02:19 PM	#6
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	Um... am I the only one that's noticing 1983 351? In stock form that's good for what? 160hp, maybe? You need heads for sure. What intake is on it? The 1983 351 wasn't SEFI, and the 302 intake won't fit onto a 351. What cam do you have? A stock 89GT Hatch weighs 3100-3150 lbs, do you have a vert? Or is that the race weight? The computer shouldn't be causing the problems. Is you MAF calibrated for 24lb/hr injectors??? If not that's obviously a big problem. Here is what you should have to run a 351 on SEFI with a cam. 77mm MAF, 75mm T/B (stock is 60mm on the 89GT), adjustable FPR, 190lph fuel pump, high flow intake (TFS, Edelbrock, Holly...ect), and some good aftermarket heads. Again, TFS, Edelbrock, AFR, ect... Sounds to me like your combo may be horribly mismatched, which is why you can't get anything out of it. I'm guessing the heads are holding you back HUGE time.

04-23-2001, 03:27 PM	#7
juiceman Registered Member Join Date: Jan 2001 Location: ny Posts: 197	first off, you should be able to hit high 12's with a mostly stock 351. if you use a carb you will make more power cheaper and sooner. it takes more to get power from injection. as for parts using a 600 on a 351 is ok but will choke it up top. no less than a 650 d.p. and for the dist. use a msd unit with the msd ignition for easy hook up and tuning. 351's dont rev so dont plan on reving it past 6000 much in stock form.

04-24-2001, 04:17 PM	#8
BennyBoy Guest Posts: n/a	I agree with Unit on the statement that your engine components are mismatched horribly. It's best to stick with parts that are made to work well with eachother. On the whole carb vs. efi thing, they both have their advantages and disadvantages. EFI is way more expensive and just kind of a pain sometimes because it's all computerized and you can't do everything the old fashioned way. With a carb, pinpointing the problem is way easier than with computers. I run a 750 Edelbrock carb with RPM intake and RPM cam, stock heads, 3:1 gears, and it bogs, but not horribly after I've learned how to control my engine a little more. And it pulls harder than crap on the top end squirting 750 cfm into the intake! If I'd get rid of my stupid a$$ stock heads and run some 3.70s I'd be mid-13s with a 3200-3300 lb., 32 year old car with a sh!tty suspension! Man...I can't wait until I get some $$$! ------------------ '69 Coupe with 351W ========================= Edelbrock RPM intake, Edelbrock RPM cam, Edelbrock 750 cfm carb, Edelbrock lifters, Edelbrock double roller timing chain, Edelbrock valve springs, Accel coil, Moroso Blue-Max wires, Hedman headers, 2 1/2" pipe, glasspacks, Flex fan, Lakewood traction bars, C4, 3:1 open rear--9" 3.70:1 posi coming this summer =========================

04-25-2001, 02:06 PM	#9
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	BIG PROBLEM! the 83 351 was the epitome of the smog motor! There was no such thing as performance in the 1983 351w! It had a weak flowing set of heads, 8.2:1 compression and a camshaft with less than .400" of lift. Before you run to a carb and maybe pick up 2/10ths get a real set of heads, and an edelbrock performer RPM cam. The intake is a bigtime mismatch for the current motor, so are the 3" pipes. I'll bet that with the cam and a set of heads and no other changes you'll be deep into the 13's. ------------------ GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B+M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

04-25-2001, 09:08 PM	#10
Violent84 Registered Member Join Date: Apr 2001 Location: Shenandoah, Va Posts: 34	Changing from EFI to a caeb isn't that bad. My uncle went from 4cyl to 460. It's just a little time a little money and alot of patience. I like my carb setup on my 84. I think if I had an EFI setup I would learn it and do the best to build horsepower and stay efficient. They both have benefits. I say research the topic and decide based upon personal prefference. later, Violent ------------------ 84 GT-350, 2.5" Ram air hood, Centerline Pintails, 5-lug conversion, Recaro's, 140 speedo, 8.8 conversion, 3.73's, Motorsport A/C eliminator, Hurst shifter, ASP pulleys, Eibach pro kit, KYB's, Flowmaster exhaust, Long tubes, Custom X-pipe, Extreme Energy 268 Ported stock heads, Pete Jackson Gear drive, Weiand Xcelerator intake, 3-core radiator,and more to come!