408 build. Am i headed in the right direction??
06-25-2016, 11:35 PM
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408 build. Am i headed in the right direction??
Okay new to site so bare with me.
I have a 2006 Chevy Silverado vortec max 4x4 crew cab. I bought the truck a year ago. It already had some engine work done. It had been rebuilt the bored it over slightly and ground the crank and repolished. (Not sure if this is right) .10 over on cylinder walls and .10 under on crank. When he rebuilt it this is what he added.
Afr 1510 heads 210s
Comp cam 54-451-11
Some comp rocker arms 1.8 ratio
Mahle pistons
And scat 6.125 ibeam rods
Still was at stock compression
no tune and stock intake and exhaust.
Some how I got sand in the motor pretty much wiped it out. It had an after market cold air intake it could've got sucked in there. And the oil cap was a pos bought from advance that didnt fit right and I didn't realize till after trail riding it was gone...
Anyway. I was losing oil pressure so I pulled the oil pan and indeed found sand in the corners of the oil pan. Put a melling high volume high pressure pump and got another 6 months out of the motor until the oil pressure started to drop below 20lbs at hot idle. So I decided to pull it and rebuild it.
As we got the motor out and apart we started finding problems. The rocker arms looked like they were smacking the valve covers. There was damage to the rockers and valve covers. It looked as though they put it together fired it up heard the noise from them hitting, pulled it back apart and cut the baffles out of the valve covers so the rockers would clear (which they still weren't). And now since the baffles were cut out it was sucking oil from the valve covers into the intake. The pistons were shot. The crank was scored but instead of grinding it under again I decided to go with a new forged crank. Which is when I said screw it and decided on going with a 408. Since I already had to buy pistons and crank I figured why not.
So this where I'm at now.
Had the block bored to 4.030
Reworked the heads. Needed I few valve guides and he redecked em.
Went with lunatti 4in crank
New mahle pistons
Same rods scat 6.125
Comp pro magnum rockers (1.8 ratio)
Comp cam 54-426-11
Comp lifters
Cloyes timing chain
Melling high volume high pressure pump. (New)
Went ahead and got the Holley tall valve covers.
Afr 1510 heads (which I know are on the small side but people run 408s with stock ls3 top ends + outta money for now lol)
1 3/4 longtubes to y pipe to a single 3in magnaflo muffler
Still running stock intake manifold and injectors... (Not by choice but outta $$)
Will this work and make some power?
I'm shooting for some low numbers
Maybe 450ish hp hopefully higher tourqe.
I know that's a small cam but I don't have the cash for a torque converter or upgrading the valve springs and I'm really not looking for high rpms either. Probably be shifting around 6500 or so. Plus everyone I talked to like comp, summit, brain Tooley and a few others all recommended around the same duration for my application. I looking more for torque and bottom end to get my boat moving. Its not a race car by any means. Just wanna give other lifted trucks a run for their money lol.
Any advice will be greatly appreciated!
I have a 2006 Chevy Silverado vortec max 4x4 crew cab. I bought the truck a year ago. It already had some engine work done. It had been rebuilt the bored it over slightly and ground the crank and repolished. (Not sure if this is right) .10 over on cylinder walls and .10 under on crank. When he rebuilt it this is what he added.
Afr 1510 heads 210s
Comp cam 54-451-11
Some comp rocker arms 1.8 ratio
Mahle pistons
And scat 6.125 ibeam rods
Still was at stock compression
no tune and stock intake and exhaust.
Some how I got sand in the motor pretty much wiped it out. It had an after market cold air intake it could've got sucked in there. And the oil cap was a pos bought from advance that didnt fit right and I didn't realize till after trail riding it was gone...
Anyway. I was losing oil pressure so I pulled the oil pan and indeed found sand in the corners of the oil pan. Put a melling high volume high pressure pump and got another 6 months out of the motor until the oil pressure started to drop below 20lbs at hot idle. So I decided to pull it and rebuild it.
As we got the motor out and apart we started finding problems. The rocker arms looked like they were smacking the valve covers. There was damage to the rockers and valve covers. It looked as though they put it together fired it up heard the noise from them hitting, pulled it back apart and cut the baffles out of the valve covers so the rockers would clear (which they still weren't). And now since the baffles were cut out it was sucking oil from the valve covers into the intake. The pistons were shot. The crank was scored but instead of grinding it under again I decided to go with a new forged crank. Which is when I said screw it and decided on going with a 408. Since I already had to buy pistons and crank I figured why not.
So this where I'm at now.
Had the block bored to 4.030
Reworked the heads. Needed I few valve guides and he redecked em.
Went with lunatti 4in crank
New mahle pistons
Same rods scat 6.125
Comp pro magnum rockers (1.8 ratio)
Comp cam 54-426-11
Comp lifters
Cloyes timing chain
Melling high volume high pressure pump. (New)
Went ahead and got the Holley tall valve covers.
Afr 1510 heads (which I know are on the small side but people run 408s with stock ls3 top ends + outta money for now lol)
1 3/4 longtubes to y pipe to a single 3in magnaflo muffler
Still running stock intake manifold and injectors... (Not by choice but outta $$)
Will this work and make some power?
I'm shooting for some low numbers
Maybe 450ish hp hopefully higher tourqe.
I know that's a small cam but I don't have the cash for a torque converter or upgrading the valve springs and I'm really not looking for high rpms either. Probably be shifting around 6500 or so. Plus everyone I talked to like comp, summit, brain Tooley and a few others all recommended around the same duration for my application. I looking more for torque and bottom end to get my boat moving. Its not a race car by any means. Just wanna give other lifted trucks a run for their money lol.
Any advice will be greatly appreciated!
06-26-2016, 05:34 AM
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Yeah I've read on other forums about upgrading to 42lbs injectors but that's for people going over 500+hp. The shop that's doing my tune said don't worry about it yet. I'm not a 100% but I'd like to think the guy doing my tune is credible lol..
06-26-2016, 11:18 AM
#5
There standard 24lb on a vortec max So there already maxed out under WOT mentioned.
The pos oil cap that got lost during trail riding likely allowed the debris to enter the engine.
The fact that things were not properly clearanced didn't help either.
Good luck on the New build! Make sure everything is properly cleaned and that you check for fitment issues upon re assembly.
The pos oil cap that got lost during trail riding likely allowed the debris to enter the engine.
The fact that things were not properly clearanced didn't help either.
Good luck on the New build! Make sure everything is properly cleaned and that you check for fitment issues upon re assembly.
06-26-2016, 02:50 PM
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I appreciate it the input! I'll go ahead and order the 42lb injectors then. The machine shop should be done any day now. Pretty much everything has been delivered so far, just need injectors and waiting to measure pushrod lengths. The trucks been down for almost a month and I can't wait to get her back on the road!!!
