Carb vs. EFI and more 351w Questions

5ohMustang · Mar 8, 2004

OK, now that I know which 351w shortblocks are OK to use, I'd like to find out more about Carb'd set ups vs EFI. What does an efi set up require that a card'd set up doesn't and vice versa?
Thanks,
Brian

hllon4whls · Mar 8, 2004

5ohMustang said:
OK, now that I know which 351w shortblocks are OK to use, I'd like to find out more about Carb'd set ups vs EFI. What does an efi set up require that a card'd set up doesn't and vice versa?
Thanks,
Brian

Basically carb setups are cheaper. I dont think that there is a real HP difference from carb to FI. A FI is more adaptable to different conditions and would drive better (economy and cold driving) than a carb.

Gearbanger 101 · Mar 8, 2004

Yeah...the Carb set up is the way to go if you're on a budget. They're actually been shown at times to produce higher peek horsepower over a similarily built EFI set up. Mind you EFI would be the way to go to retain as much low end torque as possible, improve overall driveability and make the best of your fuel economy.

GAU89LXStang · Mar 8, 2004

If you are going to be using your current car, then the carb would probably be more expensive. The carb would need a new low pressure fuel pump, carb intake, carb. The EFI would need a new lower intake. Thats it. I mean besides the normal 351W swap stuff, motor mounts, oil pan, headers...and so on. But to convert a EFI 302 to a EFI 351W(or stroker) is gonna be less than EFI 302 to Carb 351W.

Later,
Mo' Town

5ohMustang · Mar 8, 2004

Thanks for the help. I was planning on building up my 302, so I already have all of the following:
70mm TB
73mm MAF
TFS Heads
GT 40 intake
LT Headers w/ H-pipe
24lbs Injectors
1.7 Comp Cams RR
I also plan on ordering a custom cam and a 190lph fuel pump. If I have this figured out right, whether I went carb or FI, I would still need 1/2" fuel rails, 351 distributor, swap headers, swap oil pan kit, a different lower intake or a carb, a 28oz flywheel, flexplate, and harmonic balancer, and the accessory bracket. Only difference being that, w/ a carb set up, I could just sell the TB, MAF, and GT40 Intake. Have I got this correct?
-Brian

GAU89LXStang · Mar 8, 2004

Pretty much. But remember that a carb uses a lower pressure fuel pump, and no fuel rails. Me personally I go EFI, especially since you alreay have all of the stuff for it. It's more tunable, it's better overall. No need to keep messing with the carb for street and track. But this is just my opinion. Others will give you theirs. All I can say is do what you think is best.

Later,
Mo' Town

Gearbanger 101 · Mar 8, 2004

5ohMustang said:
Thanks for the help. I was planning on building up my 302, so I already have all of the following:
70mm TB
73mm MAF
TFS Heads
GT 40 intake
LT Headers w/ H-pipe
24lbs Injectors
1.7 Comp Cams RR
I also plan on ordering a custom cam and a 190lph fuel pump. If I have this figured out right, whether I went carb or FI, I would still need 1/2" fuel rails, 351 distributor, swap headers, swap oil pan kit, a different lower intake or a carb, a 28oz flywheel, flexplate, and harmonic balancer, and the accessory bracket. Only difference being that, w/ a carb set up, I could just sell the TB, MAF, and GT40 Intake. Have I got this correct?
-Brian

Why would you think that you need 1/2" fuel rails....how much power are you planning on making? Cause if so...you'd better get something bigger than the 24lb'ers and the 190lph pump while you're at it. The stock rails will work fine for what you sound like you'll be doing to it.

5ohMustang · Mar 8, 2004

A few of the pages/threads I have read said you can't use the stock fuel rails and recommend upgrading to 1/2" rails. This site (http://www.svtcobraltd.com/351swap.htm) imparticular says the stock fuel rails will not stretch over the lower intake (paragraph 5, about midway through).
Thanks,
Brian

Gearbanger 101 · Mar 8, 2004

Ahhh, yeah, I see what they mean, but I'm sure it would still be cheaper for you to have the cross over sectioned replaced, than to have a whole new set of fuel rails made up?

5ohMustang · Mar 8, 2004

yeah, you're probably right. Another question for you guys, what can you tell me about the cast numbers? I've seen a couple shortblocks for sale, but some of them only list the cast number.

5ohMustang · Mar 8, 2004

anybody else wanna throw in anything?

T_5.0_N'works · Mar 9, 2004

5ohMustang said:
A few of the pages/threads I have read said you can't use the stock fuel rails and recommend upgrading to 1/2" rails. This site (http://www.svtcobraltd.com/351swap.htm) imparticular says the stock fuel rails will not stretch over the lower intake (paragraph 5, about midway through).
Thanks,
Brian

All it is, is that little rubber fuel hose isn't long enough to connect the lines, so spend like 3 bucks and get a little longer one, easy.

whitemustang89 · Mar 9, 2004

id go carb if i was you. its cheaper,easier to tune and still gets good performance IMO

Gearbanger 101 · Mar 9, 2004

T_5.0_N'works said:
All it is, is that little rubber fuel hose isn't long enough to connect the lines, so spend like 3 bucks and get a little longer one, easy.

Well, not quite that easy. Remeber, that little rubber fuel hose is under 40+lbs of fuel pressure. He'd have to have one made up somewhere, like a place that specialized in hydraulic fittings (either rubber or braided) with the proper ends so that it wouldn't leak or blow out when the pressure was on.

5ohMustang · Mar 9, 2004

He'd have to have one made up somewhere, like a place that specialized in hydraulic fittings (either rubber or braided) with the proper ends so that it wouldn't leak or blow out when the pressure was on.

That was my worry too. If I went with a flat tappet cam for now, what type of power would I see?
-Brian

Gearbanger 101 · Mar 9, 2004

All depends on the type of cam and what the car is being used for. You'll get a hundred different responses as to what type of cam to use, but rather than just give my opinion (which is a conservative dual grind FWIW), I'll set you up with a CompCams link that will send you in the right direction.
http://www.compcams.com/Technical/CamSelection/
Off the top of my head though, with a decent set of heads (ported or otherwise) and intake, you could be looking at anywhere from 10-20hp with the properly selected grind.

gearheadboy · Mar 9, 2004

Well, if I am not mistaken, you can use the rails off of a 5.8L truck. JUNK YARD. As far as I am conserned, I'd run fuel injection if my car was originally injected, but a carb set-up is easy, cheaper, and delivers just the same performance. You just gotta know how to set your carb up. If your not racing a points game, just street cruisin and doing some weekend track times, get a carb w/a choke, have someone set it up for you, and it will please you. We had carbs for a lotta years. They work. Its gonna be a Demon for me.
I prefer a roller shaft, but they are exspensive. If ya wanna see how that flat tappet is gonna do, look up at HLLON4wheels's ride. He's got one and his car ROCKS!

SPEED FREAK · Mar 9, 2004

I just used my stock rails and used new peices of FI hose that where cut to length. Easy; done. I believe any good hose is rated for something like 60 PSI so no worries there. I have not had a problem as of yet.

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