Printable View
Well. First Post. Here goes...
I hope I put this in the right section of the forums.
I am building a LM7 (5.3) motor into a 383. I know this kind of build has been done before but I am having trouble finding information on the build. I will be using an ls1 or ls6 grind cam and either some ported 5.3 heads or some ls6 heads. The question I have is what kind of upgrades would the fuel system need to support this kind of build?
Thanks,
Ty
NA? a walbro 255 would be fine, you plan on staying NA or gonna force induct it? theres alot of verribles to concider, pending on what youre wanting to do. let us know more of what youre thinking and how you really want this motor to perform. is there a rwhp limit you wanna achieve? you call make this on a budget? give us a little more detail and i bet a few of us could help ya out !!
ok. this will be a N/A motor (no boost). I want to use it in my truck for towing and maybe a lil strip action. Looking to do it on a budget (well that is relative. haha) but I want some good hp and tq out of it while still being somewhat fuel efficient as it will be a daily driver.
what kind of injectors should i use? what is the stock size injector?
If no nitrous or anything, the stock truck injectors would probably work. Virgil is running those. Stockers are around 24#. The flex fuel injectors are 36# though, if you plan on adding a little spray.Quote:
Originally Posted by blackout
Quote:
Originally Posted by skeet
So it sounds like between the 255 walboro and the stock 24# injectors i should be set. Anyone have a link to a source for that walboro 255?Quote:
Originally Posted by pl4yboy
Walbro - SummitRacing.com
and i think allen sells them, but not sure
so is this the pump i need?Quote:
Originally Posted by skeet
Walbro GSL392 - Walbro High Pressure Inline Fuel Pumps - Overview - SummitRacing.com
another question...
If i decide to go with the 5.3 Heads which cast number 5.3 heads should i get? 241, 706, or 862 heads? Or are they all the same?
no you want the internal pump, you'll have to modify the bucket to make it work. its a simple task. you plan on having any port work done to the heads?
here ya go
Walbro Electric In-Tank Fuel Pumps - SummitRacing.com
which one of the pumps on that page is the one i want? and is there a thread on here that talks about that modification to the fuel pump bucket?Quote:
Originally Posted by skeet
and yes I plan on having the heads ported.
243s for NA.Quote:
Originally Posted by blackout
aren't the 243 heads off an ls1?Quote:
Originally Posted by pl4yboy
They were also on LS2 engines.
I have some 241, 862, and 706 heads available for a decent price. Would the 241 LS1 heads be more desirable than the 706 and 862 5.3 truck heads?
Also on the newer GMT900 5.3s.Quote:
Originally Posted by RedHeartbeat
The 241s would be your next best option if I remember correctly, but I would think you could find some 243s cheap enough nowadays to make it worthwhile. The 241s don't flow as good as the 243s, but make around the same compression I think. With a good port job, your 241s could flow decently well though. After all, they were used some sweet F-bodies.
Here's a link with a little info, not much.
241 heads vs 243 heads - Page 3 - LS1TECH
So if i decided to go with the 243 heads or perhaps the 241 heads, would i need a different intake manifold and/or any other parts? or can i use all my stock 5.3 stuff?
Stock 5.3 intake would work.
So it appears that there are two different types of 243 heads, the ls2 heads and the ls6 heads. Is it really worth it for this build to get the ls6 heads over the ls2 heads?
They flow the same, just different springs IIRC.Quote:
Originally Posted by blackout
243 heads have two different setups, one setup from the corvette LS6 will have sodium filled exhaust valves and the 243 heads from all other vehicles have the old standard plain valves.
Thats what it was, the valves.Quote:
Originally Posted by RedHeartbeat
so which 255 lph fuel pump on this website do i need? Walbro Electric In-Tank Fuel Pumps - SummitRacing.com And what kind of modifications do i have to do to make it work?
your going to need bigger injectors, them stock 24#'s won't cut it.
I think i have narrowed my build down to the 243 heads and an ls6 cam on top of the 383 bottom end. You really don't think the 24# injectors will be enough with that walboro 255 lph pump?Quote:
Originally Posted by bluecajun5.3
haha nope.Quote:
Originally Posted by blackout
they weren't enough for my mild cam only 5.3 (325ci)
ok so if my 24# injectors aren't big enough, which injectors should i get?
If you're not going FI, I would get some 42's. Direct swap and should be more than enough.Quote:
Originally Posted by blackout
So where would one go about sourcing out these higher # injectors? and which pump would work with these injectors in my truck?Quote:
Originally Posted by ramair2002
He isn't going FI, but either the 36#'s or 42#'s would work. You can get the 42s from Nelson, and the 36's come stock on Flex Fuel trucks.Quote:
Originally Posted by ramair2002
Get a better cam. And yes, the 255 will work fine for you.Quote:
Originally Posted by blackout
This truck will be my daily driver and my tow rig thats why I choose the LS6 cam. I want the vehicle to still be somewhat fuel efficient. What kind of cam did you have in mind?Quote:
Originally Posted by pl4yboy
Believe the ls6 makes power up higher....for a daily driver/tow rig you want it lower in the RPM range
TR220 or similar. Small stall converter.Quote:
Originally Posted by blackout
So how would I go about finding a TR220 cam?Quote:
Originally Posted by pl4yboy
Thunder Racing, Comp Cams, or get a custom spec'd one by Pat G.Quote:
Originally Posted by blackout
So you think like a TR220 cam would do the trick? How does one of those compare to the LS6 cam? And would some 28.5# injectors be enough to power this set up with an LS6 cam or a TR220 cam?
If V can use stock 24#s on his 370 with a monster cam, IDK why you couldn't use em with that baby cam. Might go with the 36's or 42's, depending on how much fuel that 383 needs and your driving routine.Quote:
Originally Posted by blackout
What risk would I run by initially running the truck with the 24# injectors with the walboro 255lph pump? (That is if the 24# injectors aren't enough) the truck will be tuned by a pro after the build is done, its just I will need to at least run the truck to get it to his shop if not drive it for a week or so before I can get it to his shop.Quote:
Originally Posted by pl4yboy
Or on the other hand, would I run any risk by running the truck untuned with either 28.5# or 36# injectors?
Sorry I am new to this stuff.
If you baby it, you'll probably be okay. The only thing you have to worry about is the injectors overworking, ruining, and leaning you out.Quote:
Originally Posted by blackout
So If I went with some 36# injectors and they ended up being bigger than my set -up needed, what risk would I run?
Quote:
Originally Posted by blackout
Not a thing! You don't risk anything running oversized injectors.
So even if my motor didn't need as much fuel as the 36# injectors can deliver my tuner can make them deliver less fuel? or how does that work?