Newb questions
Thread Starter
Teching In
Joined: Sep 2006
Posts: 1
Likes: 0
Newb questions I've dug through most of the FAQ's and used the search function, but didn't quite find the info I was looking for, though maybe it was already posted.
I'm looking at getting a '99 5.3 liter truck engine as a basis for a hot rod project. There are several at the local junk yard for fairly reasaonble prices. I'd considered a gen I 350 junkyard mill, but by the time I put on new heads, cam intake and carb for decent power, I'm out a couple of bucks. For the cost of a set of Vortec heads, I can get a complete 5.3l mil.
So, the question is, do I make it old style by putting a conventional intake and 4bbl on it, or if the FI is complete, put an aftermarket box on it? I don't want to spend $2k on controls, but if I can use the MEFI controller or something similar, I'd debate sticking to EFI.
The next question is on cams or higher ratio rockers. I know the stock head is limited on how far you can open the valves. Can you go to 1.6:1 rockers with the stock cam to gain a bit of flow, or are there any aftermarket cams that work well w/o having to work the head over to open the valves more?
I'm looking at getting a '99 5.3 liter truck engine as a basis for a hot rod project. There are several at the local junk yard for fairly reasaonble prices. I'd considered a gen I 350 junkyard mill, but by the time I put on new heads, cam intake and carb for decent power, I'm out a couple of bucks. For the cost of a set of Vortec heads, I can get a complete 5.3l mil.
So, the question is, do I make it old style by putting a conventional intake and 4bbl on it, or if the FI is complete, put an aftermarket box on it? I don't want to spend $2k on controls, but if I can use the MEFI controller or something similar, I'd debate sticking to EFI.
The next question is on cams or higher ratio rockers. I know the stock head is limited on how far you can open the valves. Can you go to 1.6:1 rockers with the stock cam to gain a bit of flow, or are there any aftermarket cams that work well w/o having to work the head over to open the valves more?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
If you get an engine with the wiring, computer and all the sensors I would definently say go with EFI. If you can handle the modification of your own harness it should end up costing you less than if you bought the parts to convert to a carb. The harness mods are not that difficult especially if you can read a wiring diagram and have some knowledge of what sensors you want/need to keep. Theres no reason to go with an aftermarket computer for a mild motor, just have your computer reprogrammed, its cheaper and all the wiring will plug right in. Jesse at wait4me and speartech are both sponsors here and can reprogram your computer, or even rework your harness if you decide not to tackle it yourself.
As to your other question....I`m out, I haven`t dug into the insides of the LSx motors......yet
As to your other question....I`m out, I haven`t dug into the insides of the LSx motors......yet
GO with the MEFI package from UMI Racing in Scottsdale, AZ. THe harness bolts right up and the computer is pre-programmed to fire your 5.3L right up. They also link the controller with the Racepak dash kits which makes a very clean, funtional sytem.
TECH Resident
Joined: Dec 2004
Posts: 841
Likes: 0
From: Baltimore, MD.
Hi Paul, welcome to the forum....
The LSx series of motors is a great platform, but can still be expensive (especially compared to a SBC). Camshafts for LSx's are in the $350 range, which is pretty pricey compared to the SBC offerings. Good news is the 5.3 comes with 1.7:1 roller fulcrum rockers from the factory (no stamped steel POS's like you'd find on a SBC).
Since you're building a hotrod, you're probably not hindered by the smog police, and therefore have lots of options (unlike some of us who are hot-rodding late model stuff in states that have emissions).
1.) Going carb'd is a possibility, but the manifold, carb, and ignition system represent a fairly large chunk of $$$.
2.) Depending upon the condition of the harness, you could basically just run it as is, with some stuff edited out of the PCM. Probably the least cost, but gives you the least control of stuff.
3.) You could run the factory EFI on some aftermarket hardware. There are a bunch out there, most of which are fairly pricey. The only exception I know of is MegaSquirt, which is reasonably cheap, mostly because its a DIY setup (you can even get it unassembled like an old Heathkit TV). Depending upon your choices, you can certainly spend some $$$ here....
Or, you could take that money and funnel it into a decent SBC. Factory ratings on the 5.3 are around 295hp, but the specific number depends upon year and chassis it was installed in. It doesn't take all that much work or $$$ to get a SBC to make 300hp (in non-smog trim).
Another thing to consider is accessories. The SBC and LSx stuff don't interchange. So a low mount alternator kit for a SBC won't work on an LSx 5.3L. You'll need to make sure that you have room for the truck accessories or have the $$$ to swap to some other access setup (f-body, C5 vette, custom stuff, whatever you choose).
Last point, and then I'll let you ponder other folks opinions. The intake on the 5.3l truck motor is UGLY. There are no 2 ways about it. The only way it looks decent is with the beauty covers on. So, you either need to make sure you have room for the covers or swap to a car intake manifold (which will not work with the truck accessory drive without modifying the drive.)
Sorry that I don't have an easy answer for you. But that's probably not what you're looking for anyway, is it? After all, its Your hotrod, not mine.....
Good luck with it.
'JustDreamin'
The LSx series of motors is a great platform, but can still be expensive (especially compared to a SBC). Camshafts for LSx's are in the $350 range, which is pretty pricey compared to the SBC offerings. Good news is the 5.3 comes with 1.7:1 roller fulcrum rockers from the factory (no stamped steel POS's like you'd find on a SBC).
Since you're building a hotrod, you're probably not hindered by the smog police, and therefore have lots of options (unlike some of us who are hot-rodding late model stuff in states that have emissions).
1.) Going carb'd is a possibility, but the manifold, carb, and ignition system represent a fairly large chunk of $$$.
2.) Depending upon the condition of the harness, you could basically just run it as is, with some stuff edited out of the PCM. Probably the least cost, but gives you the least control of stuff.
3.) You could run the factory EFI on some aftermarket hardware. There are a bunch out there, most of which are fairly pricey. The only exception I know of is MegaSquirt, which is reasonably cheap, mostly because its a DIY setup (you can even get it unassembled like an old Heathkit TV). Depending upon your choices, you can certainly spend some $$$ here....
Or, you could take that money and funnel it into a decent SBC. Factory ratings on the 5.3 are around 295hp, but the specific number depends upon year and chassis it was installed in. It doesn't take all that much work or $$$ to get a SBC to make 300hp (in non-smog trim).
Another thing to consider is accessories. The SBC and LSx stuff don't interchange. So a low mount alternator kit for a SBC won't work on an LSx 5.3L. You'll need to make sure that you have room for the truck accessories or have the $$$ to swap to some other access setup (f-body, C5 vette, custom stuff, whatever you choose).
Last point, and then I'll let you ponder other folks opinions. The intake on the 5.3l truck motor is UGLY. There are no 2 ways about it. The only way it looks decent is with the beauty covers on. So, you either need to make sure you have room for the covers or swap to a car intake manifold (which will not work with the truck accessory drive without modifying the drive.)
Sorry that I don't have an easy answer for you. But that's probably not what you're looking for anyway, is it? After all, its Your hotrod, not mine.....
Good luck with it.
'JustDreamin'
