Heads too small for 408?
Thread Starter
Teching In
Joined: Oct 2008
Posts: 47
Likes: 0
From: wyoming
Heads too small for 408? So i spun #1 rod bearing on the dyno with my stock bottom end ls1. Perfect opportunity to go bigger/better so this week i take delivery of my new 408! New build will be
lq9
wiseco -10cc dish pistons rings gapped for a 200 shot( will be 11.1-1 comp)
compstar rods and crank
Stage 2.5 prc 5.3 heads unmilled
ms3 on 113lsa
42#lucas injectors
walbro in tank upgrade
fast ported 92/95 combo
1-7/8 Lt's with true duals dumped
ls7 lifters / chromoly 7.4 pushrods
My question is how bad will my heads choke down flow on the bigger cubes? I am just swapping all the brand new parts from my 347 to the new 408. Any thoughts or experience with a similar setup is greatly appreciated. Any ideas what power this combo is capable of?
__________________
lq9
wiseco -10cc dish pistons rings gapped for a 200 shot( will be 11.1-1 comp)
compstar rods and crank
Stage 2.5 prc 5.3 heads unmilled
ms3 on 113lsa
42#lucas injectors
walbro in tank upgrade
fast ported 92/95 combo
1-7/8 Lt's with true duals dumped
ls7 lifters / chromoly 7.4 pushrods
My question is how bad will my heads choke down flow on the bigger cubes? I am just swapping all the brand new parts from my 347 to the new 408. Any thoughts or experience with a similar setup is greatly appreciated. Any ideas what power this combo is capable of?
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They're at least 220cc volume heads, so they will be okay to feed the engine (plus they flow pretty good). If you can have them opened up for a 4.00" bore, it would help, but you'll be okay.
You'll be fine but I wouldn't keep that cam. You will be leaving power on the table with that cam.. I am building a 408 as we speak and I am going to use the Trick Flow 215cnc heads I have now.. I am getting someone to custom spec/cut me a cam shaft to use these heads with that motor. I am also switching from a ported fast 90mm to a ported Victor jr. with the elbow to make sure I can pull the air needed into the motor to make power.. I should be able to spin the motor and still make power to around 7000rpm (give or take a few hundred rpm) and the power under the curve is going to be insane from what I can tell..
Good luck with the build!!
Good luck with the build!!
bold faced-could you please elaborate on this? thanks!
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Hey fella, I have the EXACT SAME COMBO AS YOU
Except that my MS3 is a 114LSA. Torque down low is going to be amazing with this setup I think, especially with the PRC heads.
So much for being original for me I guess
Anyways, the heads will do fine and there are quite a few that have broken 500whp with these heads on 402/408s. You can always upgrade later, that is what I am doing. Skimp out on the heads for now and save up for a set of 255cc ET heads
My 408 is going in next weekend finally.
Except that my MS3 is a 114LSA. Torque down low is going to be amazing with this setup I think, especially with the PRC heads.So much for being original for me I guess
Anyways, the heads will do fine and there are quite a few that have broken 500whp with these heads on 402/408s. You can always upgrade later, that is what I am doing. Skimp out on the heads for now and save up for a set of 255cc ET heads My 408 is going in next weekend finally. Thread Starter
Teching In
Joined: Oct 2008
Posts: 47
Likes: 0
From: wyoming
thanks for the replies everyone and the advice. I am running low on funds for the build, so the heads and cam will have to do for now. I might be leaving some on the table but a nitro daves 200 plate kit should take care of that
on a side note: what would be a good stall for this combo as i am doin a th350 swap at the same time. I was thinking an ss4000?
on a side note: what would be a good stall for this combo as i am doin a th350 swap at the same time. I was thinking an ss4000?
We've seen 500rwhp 408s with those cylinder heads so I think you'll be fine. Ideally one day you can sell those things & upgrade to something like the PRC 237cc head. They recently made over 30rwhp more than a leading aftermarket casting cnc 225cc head on back to back engine dyno testing!!
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
