475-500hp L33?
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On The Tree
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475-500hp L33? Hey guys, few friends and I are building up a super budget road race car from an old G body. We won't be entering it into any competitive class but just using it to have fun on some road courses on open track days.
The car should end up around 2900lbs race weight w/o driver and we'll be using a T56 transmission.
The car should end up around 2900lbs race weight w/o driver and we'll be using a T56 transmission.
I want to build an aluminum 5.3 (probably L33) for it on as tight as a budget as possible, but I really want to make somewhere in the 475-500HP range to the crank.
I know this is a tall order, but we do have two advantages over a typical 5.3 build; one being we'll be running pump E85 and two is that street manners really aren't a concern.
I had the idea of running flat top pistons from a 4.8L and milling the heads, or maybe finding some drop in pop up pistons. We have the budget for a full BTR top end/cam kit but will it be possible to make that kind of power with just a cam and as much compression as we can squeeze out of it running on e85?
Will the SBE be alright? Unfortunately aftermarket heads probably won't be in the budget, but maybe some cheap porting work on the stockers could be.
Any advice is appreciated.
I know this is a tall order, but we do have two advantages over a typical 5.3 build; one being we'll be running pump E85 and two is that street manners really aren't a concern.
I had the idea of running flat top pistons from a 4.8L and milling the heads, or maybe finding some drop in pop up pistons. We have the budget for a full BTR top end/cam kit but will it be possible to make that kind of power with just a cam and as much compression as we can squeeze out of it running on e85?
Will the SBE be alright? Unfortunately aftermarket heads probably won't be in the budget, but maybe some cheap porting work on the stockers could be.
Any advice is appreciated.
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From: Central Cal.
SBE will be fine, but getting that kind of dependable power on a budget build is pushing it. I say "dependable" because if you half-*** anything about it, it blows, both engine AND budget.
Thread Starter
On The Tree
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I definitely agree though that pushing the limits may not be a good idea on such a tight budget, especially on a motor that will probably see some abuse like this.
I'd still like to see what I need to do to try to achieve the goal, but in the mean time I may start trying to research what a more reasonable goal would be for a cam only 5.3 on E85
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From: Central Cal.
The SBE will be fine at that power level IF you make sure it is in good shape, IE, not worn out, the oil pump is good, and you use good oil.
Still, getting 500 NA HP from a 5.3 is nearly at the limit, and then ALL that power will be up top, and if road racing is in the plans, you need an engine with more flexibility. Look at building for around 425 HP with a power band from about 3500 to 5500 RPM but able to rev to 6000 on the regular.
You don't need a drag engine for road work.
Still, getting 500 NA HP from a 5.3 is nearly at the limit, and then ALL that power will be up top, and if road racing is in the plans, you need an engine with more flexibility. Look at building for around 425 HP with a power band from about 3500 to 5500 RPM but able to rev to 6000 on the regular.
You don't need a drag engine for road work.
Thats a lot of HP to expect fromna 5.3 with just a cam and supporting mods. 5.7 have a hard time making that power on HCIE alone. Most 5.7 average 430-450 rwhp and the upper number is ussually through an M6. You'd have to be running high compression 13:1 on e85 with forged internals and some top of the line heads like Trickflow/Tony Mamo heads to try and get to 450ish
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I'd go decent size cam and 4:11 or 4:30 gears . along with a good freshen up of that l33, and maybe splurge on the pistons/heads. Get it dialed in on the tune and just go have fun. That's what it really sounds like this project is all about, not chasing a HP number but having fun.......
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Thats a lot of HP to expect fromna 5.3 with just a cam and supporting mods. 5.7 have a hard time making that power on HCIE alone. Most 5.7 average 430-450 rwhp and the upper number is ussually through an M6. You'd have to be running high compression 13:1 on e85 with forged internals and some top of the line heads like Trickflow/Tony Mamo heads to try and get to 450ish
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Thread Starter
On The Tree
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I'd go decent size cam and 4:11 or 4:30 gears . along with a good freshen up of that l33, and maybe splurge on the pistons/heads. Get it dialed in on the tune and just go have fun. That's what it really sounds like this project is all about, not chasing a HP number but having fun.......
You're definitely right about that. Whatever we make, we make...I can't really stretch the budget further for a stroker kit or expensive heads and because we want to do an aluminum block for weight balance and I don't think the larger displacement pullouts like an L76 will fit the budget either. If we only make 400hp, so be it. I'm sure the car will still be fun at 2900lbs but we are all used to fast cars so I figured I'd shoot for a power/weight ratio that puts the car in a low 11 second 1/4 mile range just so it doesn't feel like a dog on straights compared to our own cars LOL Either way i'm sure it will be an awesome visceral experience with a gutted interior, solid suspension joints all around, race mufflers on side pipes etc...
I am going to keep an eye out for possibly an L76/T56 pull out but I doubt I will come by one for our budget.
Just figuring I'd do everything I could to make as much power as I could.
In reference to some of the above posts, I'm definitely talking about CRANK hp. I think if we can make 450HP the car would still be really fun, but then the question is will the 5.3 make 450hp on this kind of budget and still be reliable and have a good power band for road racing? It sounds like I may have been overestimating the potential with the 475-500hp number
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You CAN get the number you want out of a 5.3, but it takes cash and the power is all up high in the rpm band. My LM7 is in that 450 range, but I have about $5k in the top end. Custom Mamo heads, custom cam, Johnson short travel lifters, manton pushrods, yella terra rockers, and a Mamo ported Fast 92 intake. With my heads, I am at 10.5:1, and run 91 octane. I turn mine about 7000 rpm to make that power, you dont want that for how you plan on using the car. I will say that my car is pretty close to 2900 lbs, and it is a rocket.
Before I built this top end, I ran 862 heads, custom cam and and LS6 intake, she was fun, and very good down low, so don't be discouraged, you can build a nice fun 5.3 on a semi tight budget.
Before I built this top end, I ran 862 heads, custom cam and and LS6 intake, she was fun, and very good down low, so don't be discouraged, you can build a nice fun 5.3 on a semi tight budget.
Last edited by babydeuce; Dec 21, 2021 at 08:18 PM.
You CAN get the number you want out of a 5.3, but it takes cash and the power is all up high in the rpm band. My LM7 is in that 450 range, but I have about $5k in the top end. Custom Mamo heads, custom cam, Johnson short travel lifters, manton pushrods, yella terra rockers, and a Mamo ported Fast 92 intake. With my heads, I am at 10.5:1, and run 91 octane. I turn mine about 7000 rpm to make that power, you dont want that for how you plan on using the car. I will say that my car is pretty close to 2900 lbs, and it is a rocket.
Before I built this top end, I ran 862 heads, custom cam and and LS6 intake, she was fun, and very good down low, so don't be discouraged, you can build a nice fun 5.3 on a semi tight budget.
Before I built this top end, I ran 862 heads, custom cam and and LS6 intake, she was fun, and very good down low, so don't be discouraged, you can build a nice fun 5.3 on a semi tight budget.
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From: Michigan
Here you go
The last combination he tested uses ported 706 heads
IMO, if you've got your oiling situation well sorted out, I wouldn't be too worried about turning 7000 RPM in a road course car. I think it would probably be a good idea to get some quality lifters like the Johnson 2110 or some of their link bar lifters, though.
The last combination he tested uses ported 706 heads
IMO, if you've got your oiling situation well sorted out, I wouldn't be too worried about turning 7000 RPM in a road course car. I think it would probably be a good idea to get some quality lifters like the Johnson 2110 or some of their link bar lifters, though.
I didn't understand why the "SBE" was such a big deal in RH video. Honestly it was ******* annoying.
We aren't talking about making 1500 on a SBE.
500.......that's it....
We aren't talking about making 1500 on a SBE.
500.......that's it....
TECH Senior Member
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From: Central Cal.
A SBC needs a lot more love and attention down under than an LS. Hence the emphasis.
Keep in mind 500HP used to be a bigger deal than nowadays. Now you just take an LS3 and stick a cam in it. Used to take a lot more than that to get that out of a BBC.
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From: St. Louis
This would be cheap high RPM 5.3L and what I would do, just get a good oil pan and pickup with a nice melling pump and use a Stock crank with 4.8 Pistons on the heavier duty 04-06' rods with some arp bolts and snap in some new summit main and rod bearings if the old ones look bad.
A stock untouched j/y short block with only an oil pump upgrade still may be more reliable so...
Tourque to factory specs and cross fingers...
On top just do clean stock #706 heads with ls6 springs. If it breaks little risk here...
Comp 54-777-11 drift cam is the most expensive part...
233/243 duration 114lsa +5 advance .541/.541 lift
Stock lifters from an earlier gen 3 engine 98-06 and longer Btr 0.080 wall 7.450" pushrods will survive fine.
LS2 timing chain and stock gears dot to dot with a little slop is perfect
do a trunnion upgrade if you want but I never do
Ls6 intake manifold or something similar.
This is 7500 RPM All day I have an 06' j/y LQ9 with the same valve train mine is unopened cam only and it's easy and reliable
A stock untouched j/y short block with only an oil pump upgrade still may be more reliable so...
Tourque to factory specs and cross fingers...
On top just do clean stock #706 heads with ls6 springs. If it breaks little risk here...
Comp 54-777-11 drift cam is the most expensive part...
233/243 duration 114lsa +5 advance .541/.541 lift
Stock lifters from an earlier gen 3 engine 98-06 and longer Btr 0.080 wall 7.450" pushrods will survive fine.
LS2 timing chain and stock gears dot to dot with a little slop is perfect
do a trunnion upgrade if you want but I never do
Ls6 intake manifold or something similar.
This is 7500 RPM All day I have an 06' j/y LQ9 with the same valve train mine is unopened cam only and it's easy and reliable
Last edited by stockA4; Dec 26, 2021 at 12:05 PM.
