408 build advice
408 build advice Hey guys, I'm in a process of getting parts to put together a 408. As of right now all I have is a 6 liter iron block. As this my first engine build I'm looking for advice on what to get. I'm looking towards 500whp NA with a flat torque curve. I'm most likely gonna be ordering a complete rotating assembly from Texas speed. But what about heads and cam? Which ones should I get. And what else would I need besides the rotating assembly. Thank you for the help
TECH Fanatic
Joined: Oct 2015
Posts: 1,280
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From: Pittsboro, IN
Bang for the buck I would get some CNC 243 heads.
This is a quote from Thompson.
This is a quote from Thompson.
We do use them on our long blocks. The power output depends on the surrounding circumstances. The one that we have done the most R&D in is our 408 hydraulic roller 10.0:1 pump gas build to work with our most popular street motor. It makes 601HP and 505TQ. We have options for smaller motors with smaller camshafts that will hit in the 550-570 range. We can cam these for small or large motors to work excellent all the way around the board.
Thank you,
Kyle
972-853-2450
Thank you,
Kyle
972-853-2450
I'd go 1.0mm over bore (.040") DNJ hyper pistons on production rods and crank for 372 cubes; approximately 11.25:1 compression ratio
Texas Speed PRC 225cc as cast heads and their 228/232 range cam
with 1&7/8" headers and a FAST 92 intake you would have a strong user
friendly combo that would have power everywhere
And if it only makes 450 or 470 rear wheel horsepower; that's still quite a
powerful "first engine"
Texas Speed PRC 225cc as cast heads and their 228/232 range cam
with 1&7/8" headers and a FAST 92 intake you would have a strong user
friendly combo that would have power everywhere
And if it only makes 450 or 470 rear wheel horsepower; that's still quite a
powerful "first engine"
I'd go 1.0mm over bore (.040") DNJ hyper pistons on production rods and crank for 372 cubes; approximately 11.25:1 compression ratio
Texas Speed PRC 225cc as cast heads and their 228/232 range cam
with 1&7/8" headers and a FAST 92 intake you would have a strong user
friendly combo that would have power everywhere
And if it only makes 450 or 470 rear wheel horsepower; that's still quite a
powerful "first engine"
Texas Speed PRC 225cc as cast heads and their 228/232 range cam
with 1&7/8" headers and a FAST 92 intake you would have a strong user
friendly combo that would have power everywhere
And if it only makes 450 or 470 rear wheel horsepower; that's still quite a
powerful "first engine"
If that's the case, I would do a 370"...spend the extra $1,000 you were gonna put on the stroker crank on the heads. It will be BADASS!
I agree! I don't even have my 408 running yet and already wish I would have done some things differently. A great set of heads is where the power's at.
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Verdad Gallardo Killer heads on a 370 is better than just good heads on a 408
Cubic inches, specially from stroke becomes a law of diminishing returns. Piston Speed, ring friction and rod angularity all become power robbing factors. It will make more torque but usually makes a lower horse per cube ratio. Your money; just giving you free knowledge
That five hundred bucks would be the difference between some Re done 243/799 heads and perhaps a set of Mamo 223 Sportsman's or some Tooley touched up Trick Flow 220 as cast heads.
Killer heads on a 370 is better than just good heads on a 408
Cubic inches, specially from stroke becomes a law of diminishing returns. Piston Speed, ring friction and rod angularity all become power robbing factors. It will make more torque but usually makes a lower horse per cube ratio. Your money; just giving you free knowledge
Killer heads on a 370 is better than just good heads on a 408
Cubic inches, specially from stroke becomes a law of diminishing returns. Piston Speed, ring friction and rod angularity all become power robbing factors. It will make more torque but usually makes a lower horse per cube ratio. Your money; just giving you free knowledge
IMO this build would suit your power goals reliably
It would be foolish to bore the block out to fit bigger pistons if you do not have to.
If you are good at 30 over, there is no reason to go any bigger.
60 over on an iron block is pushing it, 65 is even worse.
Plus in the long term if you stay 30, you could rebuild to 40 or 60 down the road.
No need to max bore at this time.
If you are good at 30 over, there is no reason to go any bigger.
60 over on an iron block is pushing it, 65 is even worse.
Plus in the long term if you stay 30, you could rebuild to 40 or 60 down the road.
No need to max bore at this time.
PS: forget stock rods. Go forged pistons and rods and do it right. As far as size, if you want tq, the 4 inch stroke of a 408 will win hands down.
I had a forged 6.0 and it was a solid motor, but never put down the tq of comparable 408s. But it was a monster on the bottle.
if you want to build something, spend the money on solid parts. If you are going to use stock parts, go to a yard and pull a motor. It will be cheaper.
I had a forged 6.0 and it was a solid motor, but never put down the tq of comparable 408s. But it was a monster on the bottle.
if you want to build something, spend the money on solid parts. If you are going to use stock parts, go to a yard and pull a motor. It will be cheaper.
PS: forget stock rods. Go forged pistons and rods and do it right. As far as size, if you want tq, the 4 inch stroke of a 408 will win hands down.
I had a forged 6.0 and it was a solid motor, but never put down the tq of comparable 408s. But it was a monster on the bottle.
if you want to build something, spend the money on solid parts. If you are going to use stock parts, go to a yard and pull a motor. It will be cheaper.
I had a forged 6.0 and it was a solid motor, but never put down the tq of comparable 408s. But it was a monster on the bottle.
if you want to build something, spend the money on solid parts. If you are going to use stock parts, go to a yard and pull a motor. It will be cheaper.
That five hundred bucks would be the difference between some Re done 243/799 heads and perhaps a set of Mamo 223 Sportsman's or some Tooley touched up Trick Flow 220 as cast heads.
Killer heads on a 370 is better than just good heads on a 408
Cubic inches, specially from stroke becomes a law of diminishing returns. Piston Speed, ring friction and rod angularity all become power robbing factors. It will make more torque but usually makes a lower horse per cube ratio. Your money; just giving you free knowledge
Killer heads on a 370 is better than just good heads on a 408
Cubic inches, specially from stroke becomes a law of diminishing returns. Piston Speed, ring friction and rod angularity all become power robbing factors. It will make more torque but usually makes a lower horse per cube ratio. Your money; just giving you free knowledge
Hey guys, I'm in a process of getting parts to put together a 408. As of right now all I have is a 6 liter iron block. As this my first engine build I'm looking for advice on what to get. I'm looking towards 500whp NA with a flat torque curve. I'm most likely gonna be ordering a complete rotating assembly from Texas speed. But what about heads and cam? Which ones should I get. And what else would I need besides the rotating assembly. Thank you for the help
I'm finishing up my LS3 headed 6.0L iron block build, but I went with a little more stroke than 4". Feel free to read my build thread here.
LS3 heads on a 408ci engine should make that and then some. You could probably even do it with a stock ported LS3 intake, but there are some good aftermarket intakes too.
I'm finishing up my LS3 headed 6.0L iron block build, but I went with a little more stroke than 4". Feel free to read my build thread here.
I'm finishing up my LS3 headed 6.0L iron block build, but I went with a little more stroke than 4". Feel free to read my build thread here.
However, on a 400ci engine, they're more appropriately sized. They'll have good airspeed, good low end power, and will still be able to feed a larger engine like a 408. You're going to have to spend a lot more money on a cathedral head to get the same performance.