Building a 408...is this a dumb idea??
Building a 408...is this a dumb idea?? Alright I finally decided to stop being cheap and get a 408 
My original plans were a forged low compression 370 and having a local fabricator/turbo guru build me a nice single turbo kit. Well things arent working out the way I want...he is backed up with other projects, and in the meantime my car is down.
Soo I have decided to have Combination Motorsports in Las Vegas build me the 408...I talked to them about a low compression setup and its everything I want. But then I got to thinking...what if I build the shortblock with some dished pistons (27cc I think), but then take the heads Im going to use and mill them in order to get somewhere between 10-10.5:1 compression, run a big cam and have fun with that for the rest of the summer...then towards Sept.-Oct. start having the turbo kit built, and then swap the heads for ones with a larger combustion chamber and bring my comp. ratio back down, and install the cam that I have that is ground for a turbo.
Would this work...or is it kind of a dumb idea??
My original plans were a forged low compression 370 and having a local fabricator/turbo guru build me a nice single turbo kit. Well things arent working out the way I want...he is backed up with other projects, and in the meantime my car is down.
Soo I have decided to have Combination Motorsports in Las Vegas build me the 408...I talked to them about a low compression setup and its everything I want. But then I got to thinking...what if I build the shortblock with some dished pistons (27cc I think), but then take the heads Im going to use and mill them in order to get somewhere between 10-10.5:1 compression, run a big cam and have fun with that for the rest of the summer...then towards Sept.-Oct. start having the turbo kit built, and then swap the heads for ones with a larger combustion chamber and bring my comp. ratio back down, and install the cam that I have that is ground for a turbo.
Would this work...or is it kind of a dumb idea??
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by 2000Z71
If you do not feel like waiting and have the extra money, go for it.
It's a waste in that you will be swapping a lot of parts, but if you have the time/money you could do that.
Are you dead set on a turbo setup?
You could always just build it up for the turbo right now and live with the lower compression in the meantime.
exactly, though your compression would be low, it wouldnt run bad at all. Just have it tuned correctly and all should be well for the turbo....
Now, that is a great idea!!!!! a 408 with a turbo....WOW!!!
Hopefully, when the suspension is done right, im just gonna drop the pistons and get somewhere close to 9.1 or 9.5...maybe 8.8 and slap a huge turbo on it!!!! of course, a trans would help keep it all alive....
good luck!!
Now, that is a great idea!!!!! a 408 with a turbo....WOW!!!
Hopefully, when the suspension is done right, im just gonna drop the pistons and get somewhere close to 9.1 or 9.5...maybe 8.8 and slap a huge turbo on it!!!! of course, a trans would help keep it all alive....
good luck!!
I am definitely dead set on the turbo...its not a $$ issue...its a "Im tired of waiting...I want my car done" issue 
As for just running the low compression setup until the turbo is built...I thought about it...but I dunno, Im just affraid that if I do that, then I wont be happy with it and it'll cost me more $$ to pull the heads, mill them, etc. Might as well just do it and then pick up some new heads for later down the road.
As for just running the low compression setup until the turbo is built...I thought about it...but I dunno, Im just affraid that if I do that, then I wont be happy with it and it'll cost me more $$ to pull the heads, mill them, etc. Might as well just do it and then pick up some new heads for later down the road.
TECH Junkie
Joined: Dec 2001
Posts: 3,242
Likes: 0
From: Lakeland, FL
if its not a dollar issue maybe find somebody else or just wait, If you want turbo just to it the normal way the 1st time,, but then again if money is not an issue what do you have to lose,
You could always build it for NA right now get the flat top pistons and reg heads then just sell off the heads when you are ready to do turbo, just make sure and get some heads that people will buy at a high price.
You could always build it for NA right now get the flat top pistons and reg heads then just sell off the heads when you are ready to do turbo, just make sure and get some heads that people will buy at a high price.
Well Ive always wanted a 408 with decent compression and a big cam...which would be ALOT of fun...and I figure if I do it this way...I can have my cake and eat it too, by running it n/a for a while then adding boost and making some big #'s.
I guess I better call up Combination and place my order
I guess I better call up Combination and place my order
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If your defentially going turbo I would build it around the turbo as far as the pistons go. Lets say you want to end up with 8.8 CR with the turbo.
With a ,054 gasket you will need a 71cc head (LQ9 stock size) and a -23cc piston.
For now though you want as much compression as possible.
If you take a LS6 head and mill it to 58cc's and run a .030 gasket you will get 10.4:1 compression.
To get it much higher then that is going to be a challenge.
Remember though you might have a touch sell once you switch to turbo as the heads are milled a lot.
Many solid roller heads are 54-56 cc's and LS6 heads so it is possible.
A 54cc head would get you 10.85:1
With a ,054 gasket you will need a 71cc head (LQ9 stock size) and a -23cc piston.
For now though you want as much compression as possible.
If you take a LS6 head and mill it to 58cc's and run a .030 gasket you will get 10.4:1 compression.
To get it much higher then that is going to be a challenge.
Remember though you might have a touch sell once you switch to turbo as the heads are milled a lot.
Many solid roller heads are 54-56 cc's and LS6 heads so it is possible.
A 54cc head would get you 10.85:1
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Originally Posted by JZ'sTA
If your defentially going turbo I would build it around the turbo as far as the pistons go. Lets say you want to end up with 8.8 CR with the turbo.
With a ,054 gasket you will need a 71cc head (LQ9 stock size) and a -23cc piston.
For now though you want as much compression as possible.
If you take a LS6 head and mill it to 58cc's and run a .030 gasket you will get 10.4:1 compression.
To get it much higher then that is going to be a challenge.
Remember though you might have a touch sell once you switch to turbo as the heads are milled a lot.
Many solid roller heads are 54-56 cc's and LS6 heads so it is possible.
A 54cc head would get you 10.85:1
With a ,054 gasket you will need a 71cc head (LQ9 stock size) and a -23cc piston.
For now though you want as much compression as possible.
If you take a LS6 head and mill it to 58cc's and run a .030 gasket you will get 10.4:1 compression.
To get it much higher then that is going to be a challenge.
Remember though you might have a touch sell once you switch to turbo as the heads are milled a lot.
Many solid roller heads are 54-56 cc's and LS6 heads so it is possible.
A 54cc head would get you 10.85:1
Im planning on being around 9:1 or 9.5:1 at the max. And anything around 10.5:1 with milled heads would be perfect, as Az is HOT and we only have 91 octane
. Im also going to run a decent size turbo but keep the boost mild @ 8-12lbs and nothing over 15-16lbs on race gas. I will run the numbers for you again at 9:1 and get you to 10.5:1
9.1 with a .054 gasket and 71cc head is a -20cc piston.
To get 10.5:1 you will need a 59cc head and a .035 gasket, or a .030 gasket and a 60 cc head.
I would keep the compression at 9:1 and stay away from 9.5:1
Your gonna want to turn the boost up one day Im sure.
9.1 with a .054 gasket and 71cc head is a -20cc piston.
To get 10.5:1 you will need a 59cc head and a .035 gasket, or a .030 gasket and a 60 cc head.
I would keep the compression at 9:1 and stay away from 9.5:1
Your gonna want to turn the boost up one day Im sure.
.