5.3 budget build help
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Teching In
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5.3 budget build help New member here but long time lurker, I have a low mileage 5.3 that I'm rebuilding for a lightweight drag car and need help from people who have built these before. The engine will be a stock short block with new rings, need help picking a cam and the best stock head choice, right now i have 862's but can get whichever stock head is best for my application. The car will need to go down the streets as I plan on driving it to shows but idle quality means nothing to me as its my drag car, I'm looking for the best all out performance cam I can get and which heads I should get to go with it along with what I should do to the heads, don't know wether i should mill them or not or if i will have clearance issues, and for the top end I have a ls6 intake. I will be spraying nitrous, probably a 125 shot if that comes into play with the cam choice. Thanks in advance, let me know if you have any questions. 
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Teching In
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The car will run a 1/4, has 373 gears with 29.5 tall tire just because I have them lying around, can change if it's suggested. Race weight will come in at about 2200lbs, it is a 1946 ******. Like I said street manners aren't a big deal to me and I'm not very concerned with losing a little low end torque since I'm so light, I was thinking about some 243 heads and milling them down but Need opinions if I can reach my goal with 862s, I'd rather buy 243s then put money into the stock heads.
oh and its a 4l80e and I plan on spraying 125
Id like to get mid 400's at the crank, andbudget is pretty open will just take longer to get it all together, I would like to stick with a stock casting head if possible but its not completely a must.
The car will run a 1/4, has 373 gears with 29.5 tall tire just because I have them lying around, can change if it's suggested. Race weight will come in at about 2200lbs, it is a 1946 ******. Like I said street manners aren't a big deal to me and I'm not very concerned with losing a little low end torque since I'm so light, I was thinking about some 243 heads and milling them down but Need opinions if I can reach my goal with 862s, I'd rather buy 243s then put money into the stock heads.
oh and its a 4l80e and I plan on spraying 125
The car will run a 1/4, has 373 gears with 29.5 tall tire just because I have them lying around, can change if it's suggested. Race weight will come in at about 2200lbs, it is a 1946 ******. Like I said street manners aren't a big deal to me and I'm not very concerned with losing a little low end torque since I'm so light, I was thinking about some 243 heads and milling them down but Need opinions if I can reach my goal with 862s, I'd rather buy 243s then put money into the stock heads.
oh and its a 4l80e and I plan on spraying 125
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Teching In
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Will the flat tops just bring the compression up? And if so what will it bring it up to on a stock head with stock gasket? I can mill if needed just need it all layed out ahead of time. And I have a ls6 intake with stock throttle body to go on it, I'd like to stay with that since I paid a pretty penny for one. Also if it's possible to go with Texas speed I'd like to due to there military discount
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Flat tops will bring compression up to 10.3 - 10.5 depending on which headgaskets you use. 243 or 799 heads will drop it back down to 9.9 or so.
Even with less compression, you'll likely make more power with the 243 heads. Get them milled if you want compression.
LS6 intake will work, it'll just be a little down on power and torque compared to the newer truck intake.
Even with less compression, you'll likely make more power with the 243 heads. Get them milled if you want compression.
LS6 intake will work, it'll just be a little down on power and torque compared to the newer truck intake.
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Verdad Gallardo What year is the 5.3 you have now? I thought the new ones came with flat tops? Mine did anyway.
I think you could reach well over your HP goal with any LS head on E85. 243’s are overrated for a budget build these days IMO. ($400-600 for a used set is typical) If you can grab a set w/ the engine or at a good price that’s great, but you’d still need to mill or fill the CC to get the compression to reasonable levels. (adds to cost) The small valve truck heads no one wants are more than capable for a 400+crank HP goal.
I’d run E85 for sure. Great fuel for street and track. If you don’t plan to go over a 125 shot, I’d fill/mill the cheap heads enough to hit around 12.5:1 compression wise keeping as much PTV clearance as possible. Any of the stage 1-2-3 etc vendor shelf cams for a 5.3 will work great and reach your goals easily, but will cost around $365-425. Then you’ll likely need to upgrade push rods, springs, possibly rockers. (new lifters?) You can easily be in over $1000 on a “cam swap”.
That said… have you considered a mild turbo kit? If you can MIG weld (even poorly) you can make a turbo kit with stock exh. manifolds a 2” mild steel piping that will make 650ish WHP for less than the cost of a typical heads/cam/header NOS combo. Used LS1 cam ($25) with $50 shimmed LS6 valve springs will do it on a bone stock long block. Just a thought, I know it’s not for everyone and nitrous is great fun as well. Been wanting to throw together a 13:1 budget E85 combo like you described for a while now… I hope you stay the NA route.
I think you could reach well over your HP goal with any LS head on E85. 243’s are overrated for a budget build these days IMO. ($400-600 for a used set is typical) If you can grab a set w/ the engine or at a good price that’s great, but you’d still need to mill or fill the CC to get the compression to reasonable levels. (adds to cost) The small valve truck heads no one wants are more than capable for a 400+crank HP goal.
I’d run E85 for sure. Great fuel for street and track. If you don’t plan to go over a 125 shot, I’d fill/mill the cheap heads enough to hit around 12.5:1 compression wise keeping as much PTV clearance as possible. Any of the stage 1-2-3 etc vendor shelf cams for a 5.3 will work great and reach your goals easily, but will cost around $365-425. Then you’ll likely need to upgrade push rods, springs, possibly rockers. (new lifters?) You can easily be in over $1000 on a “cam swap”.
That said… have you considered a mild turbo kit? If you can MIG weld (even poorly) you can make a turbo kit with stock exh. manifolds a 2” mild steel piping that will make 650ish WHP for less than the cost of a typical heads/cam/header NOS combo. Used LS1 cam ($25) with $50 shimmed LS6 valve springs will do it on a bone stock long block. Just a thought, I know it’s not for everyone and nitrous is great fun as well. Been wanting to throw together a 13:1 budget E85 combo like you described for a while now… I hope you stay the NA route.
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He said he has 862s so its not a flat top engine.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
TECH Resident
Joined: Apr 2010
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From: Central Texas
He said he has 862s so its not a flat top engine.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
Thread Starter
Teching In
Joined: Apr 2017
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What year is the 5.3 you have now? I thought the new ones came with flat tops? Mine did anyway.
I think you could reach well over your HP goal with any LS head on E85. 243’s are overrated for a budget build these days IMO. ($400-600 for a used set is typical) If you can grab a set w/ the engine or at a good price that’s great, but you’d still need to mill or fill the CC to get the compression to reasonable levels. (adds to cost) The small valve truck heads no one wants are more than capable for a 400+crank HP goal.
I’d run E85 for sure. Great fuel for street and track. If you don’t plan to go over a 125 shot, I’d fill/mill the cheap heads enough to hit around 12.5:1 compression wise keeping as much PTV clearance as possible. Any of the stage 1-2-3 etc vendor shelf cams for a 5.3 will work great and reach your goals easily, but will cost around $365-425. Then you’ll likely need to upgrade push rods, springs, possibly rockers. (new lifters?) You can easily be in over $1000 on a “cam swap”.
That said… have you considered a mild turbo kit? If you can MIG weld (even poorly) you can make a turbo kit with stock exh. manifolds a 2” mild steel piping that will make 650ish WHP for less than the cost of a typical heads/cam/header NOS combo. Used LS1 cam ($25) with $50 shimmed LS6 valve springs will do it on a bone stock long block. Just a thought, I know it’s not for everyone and nitrous is great fun as well. Been wanting to throw together a 13:1 budget E85 combo like you described for a while now… I hope you stay the NA route.
I think you could reach well over your HP goal with any LS head on E85. 243’s are overrated for a budget build these days IMO. ($400-600 for a used set is typical) If you can grab a set w/ the engine or at a good price that’s great, but you’d still need to mill or fill the CC to get the compression to reasonable levels. (adds to cost) The small valve truck heads no one wants are more than capable for a 400+crank HP goal.
I’d run E85 for sure. Great fuel for street and track. If you don’t plan to go over a 125 shot, I’d fill/mill the cheap heads enough to hit around 12.5:1 compression wise keeping as much PTV clearance as possible. Any of the stage 1-2-3 etc vendor shelf cams for a 5.3 will work great and reach your goals easily, but will cost around $365-425. Then you’ll likely need to upgrade push rods, springs, possibly rockers. (new lifters?) You can easily be in over $1000 on a “cam swap”.
That said… have you considered a mild turbo kit? If you can MIG weld (even poorly) you can make a turbo kit with stock exh. manifolds a 2” mild steel piping that will make 650ish WHP for less than the cost of a typical heads/cam/header NOS combo. Used LS1 cam ($25) with $50 shimmed LS6 valve springs will do it on a bone stock long block. Just a thought, I know it’s not for everyone and nitrous is great fun as well. Been wanting to throw together a 13:1 budget E85 combo like you described for a while now… I hope you stay the NA route.
Thread Starter
Teching In
Joined: Apr 2017
Posts: 13
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He said he has 862s so its not a flat top engine.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
You'll need a little help to hit 450 HP N/A on a 5.3 with dished pistons and 862 heads. You won't be able to get the same compression as flat tops from milling alone.
I'm a turbo guy like Adam, but not everyone is.
So if you want to stay N/A, I would swap in flat tops, run stock 862 heads. You can get a Howards 226/232 112 LSA with valve springs, retainers, new valve seals, and locks for $500 in the right place (Can't post links here). This cam will work good in a 5.3 that has over 10:1 compression and still be very driveable. Speed Engineering race version long tubes are 1 7/8" primaries with a 3.5" open collector.
That will get you in the ~440-450 flywheel HP range for $1000. If you have the hood clearance, you can sell the LS6 intake and buy a TBSS with ebay throttle body and possibly still have some cash left over. You'll pick up another 10-15 HP/TQ.
Few local street driven LS guys running 13:1 on E85 and loving it. Couple BBC’s as well. But I don’t know of any doing it with factory pistons/heads which is what I wanted to try.
I’m told you can have issues with the plastic intakes sealing if you go over .035 or so. That will take 5cc or so from the 61cc factory head. Putting you right around 56cc. Around 55cc with a thinner .041 MLS HG. You’ll also need shorter push rods if you go this route too ($100)
I had a thread going where this was discussed and someone linked a company that filled/welded the CC on the heads. But they have since removed the links and I don’t recall the company? I’m sure if you called up Texas Speed or any of the other performance head shops they could quote you on the head CC filling. Then supply you with a cam that would be sure to clear the valves and work well.
For the stall I'd call up PTC and go with the $450 10" budget deal.
I’m told you can have issues with the plastic intakes sealing if you go over .035 or so. That will take 5cc or so from the 61cc factory head. Putting you right around 56cc. Around 55cc with a thinner .041 MLS HG. You’ll also need shorter push rods if you go this route too ($100)
I had a thread going where this was discussed and someone linked a company that filled/welded the CC on the heads. But they have since removed the links and I don’t recall the company? I’m sure if you called up Texas Speed or any of the other performance head shops they could quote you on the head CC filling. Then supply you with a cam that would be sure to clear the valves and work well.
For the stall I'd call up PTC and go with the $450 10" budget deal.
Last edited by Forcefed86; Apr 18, 2017 at 01:34 PM.
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From: Ohio
I've seen West Coat Racing, AI, and a few other companies that will rework chambers to 53-55cc on 5.3/4.8 heads. Having them filled and machined is better than having them milled.
No reasonable compression limit on E85. Over 13:1 is where E85 starts having issues in most setups.
As far as cam, Texas Speed's military discount is 50% off shipping costs. Even with that, there are still TONS of other companies that sell cams cheaper. Cam choice will depend on final compression.
No reasonable compression limit on E85. Over 13:1 is where E85 starts having issues in most setups.
As far as cam, Texas Speed's military discount is 50% off shipping costs. Even with that, there are still TONS of other companies that sell cams cheaper. Cam choice will depend on final compression.