Im seriously thinking about putting fuel injection on my 383 because its my daily driver and has a 6 speed behind it. I really want efi, but its just going to cost so damn much mainly because of the harness and injectors. Right now I have a holley 750 double pumper with a proform mainbody w/ adjustable air bleeds. Its only 8 months old and its set up pretty well for my engine, but I get a bog if i just punch it at low rpms (WOT). One of my friends offered me 250 bucks for it (just cost over 600 a few months ago), with the money I could buy a holley 750 vacuum secondary and tune it, but am i really saving that much money buy selling my double pumper for the vacuum secondary? I get pretty decent mileage with the carb i have now, but If the vacuum secondary will be just as decent for performance and mpg, i wouldnt mind selling it and having the extra cash around.
If properly tuned you'll probably get worse mileage with the vacuum secondary carb.
As for EFI, you can use the intake system from an LT1 along with megasquirt to put together a poorman's ramjet system. Works pretty well up to about 450hp.
It's a matter of preference. I personally like the double pumper carbs because they come on when you want them to. Vacuum secondaries are OK but there's nothing better than depressing the pedal and manually giving the engine that squirt of fuel. I also run low gears which helps with carb performance. It's hard to recommend a carb because everyone has their opinions. Just like this one :welcome:
my vote would be 650 vacume secondarys,you can change springs in the 2dary diafram to have them come on sooner,tune it re prev. post. i have a 302 in my32ford that has a mild cam andported heads with biger valves the 600 holley works well,no bog. ther ar some deals on e bayfrom holley thes carbs ar returns with minor isues,i bought a newish 1 for 150 including frt,it is on another 5ltrworks great,they had larger carbs for more $ ,it is a make a offer type of auction. double pumpers will never be good on fuel relitive to vacume 2nds and sensible driveing. my opinion cliff
Just quickly review some of your old posts I can see a few things.
The cam you have is way too big for how you actually drive your car.
And it is most likely a mis match for your exhaust system.
That cam is not in the game below 2500 rpm.
You are retarding the spark timing to allow running regular gas cause you are too cheap to put good gas in the tank yet want to spend $1000's on EFI.
Retarded timing is going to effect throttle response.
Especially if it was never right in the first place. Just checking your posts,
it is not near right for that cam. Needs a lot lot of work.
Every combination is different, the performance cams like more initial timing. Also sounds like you need more fine tuning on the carb's accelerator pump circuit here is vid kinda basic but informative. http://www.youtube.com/watch?v=k-Nx5HEzvlY
Whether or not you like the comments they do carry merit. It's not about the original post but often people will attempt to change a part that works in an effort to compensate for one that isn't. Its like changing the water pump to fix a leaking heater core...
This is either/both the accelerator pump circuit and initial timing. There is no reason the carb shouldn't work on your engine- providing it's in tune and you modulate the throttle using your brain and right foot as opposed to just matting it, like can be done w/a vacuum secondary carb.
IF you have too much cam, this will manifest itself by being lazy down low in the rev band- but that's a whole 'nuther thing from a bog. Maybe a more in depth description of what's happening will help.
an lt1 setup would work, but the optispark distributor is crap, and actually wouldnt be worth messing with....
heres a junkyard parts list for an LS based fuel injection setup
any ls1 based pcm will work, you'll just have to get it reflashed, many reflash for like $50.00
heres the list
12200411 PCM (LS1, Truck, S-10, Blazer, Express, others)
Wiring Harness for 12200411 (must follow Vortec L31 schematics for the 18436572 firing order)
Vortec 305/350 Distributor (has camshaft sensor in it)
Vortec 305/350 Harmonic Balancer (if your 383 is internally balanced, if not, retain your balancer and cut the thickness of the reluctor wheel from the hub)
Vortec 305/350 Timing Cover(crank position sensor provision)
Vortec Timing Reluctor Ring (goes behind timing cover)
Vortec Crank Position Sensor
Vortec Ignition Module
Vortec Coil
Knock Sensor (2001 Express Van w/ 5.7 engine)
injection intake and rails, professional products makes a decent setup...
injectors, ford 30lb redtops would be minimum, can be found on ebay very reasonable..
i have always made it a point to run a dbl pumper with a manual transmission..
if you have a bog off idle go to a larger discharge nozzle.. if you cant get the dbl pumper adjusted correctly you'll never get a vacuum secondary carb to work correct..
F-Bird's post is spot on, but you just don't want to hear it. I feel the same way as he does, you're trying to crutch what you have rather than make it right, complain about cost but want to blow $$$ on EFI that won't even earn a return on its investment for something like 70,000 miles of driving cost.
The DP can get as good a mileage as anything, if you set it up right and keep your foot out of it.
It's guys like F-Bird88 who do their homework in here and usually give sound advice to some of us who need help on projects, myself included. :mwink: Name calling shows ignorance! After reading the posts, I think I would go with the EFI unit and run regular unleaded gas! Just my opinion...
stroker444
"Ive noticed that you find a way to be a dick just about everytime you reply."
What is the matter the truth hurts? he took the time to research your post to give you an accurate answer. Your basically being told the truth about the miss match of the parts .
Here is a link that might help sort out some of your questions
ericnova72The DP can get as good a mileage as anything said:
Ha Ha. I don't think he put it together to "keep his foot out of it". I was working on the mileage thing with the Vac. secondary by eliminating the squirt from the shooters from the DP and the fact that the vac. sec. will open on engine load, only as far as needed. In the end, mileage really depends on driving habits regardless of what kind of carb you have. With the big cam that's in there, how could mileage be a concern? Now that I think of it, put a 780cfm on it!
If F-Birds right about the cam, fuel injection isn't going to be a cure all thats for sure. Maybe just stick with the dbl pumper and get serious and change the cam and then everything will fall in place better. You will be a lot happier with it in the long run, it's not exactlly a hard job. Good luck, not sure if you are running roller rockers a tall ratio, it all helps take the load off .
Is there anyway to know much vacuum at idle this cam would make? Thats one of the most important things so my brakes will work a tad bit better. I only get 13.5-14.5 with the cam i have now at 650RPM, my brakes work, but i can only get one good pump out of them and the engine takes a while to ready the booster again.
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