newbie here from sk in canada. my 03 GMC 4.8 is toast after putting the blower on it and running with a heavy foot so I decided to not **** around and go big. I got a motor built already and would like any imput on my setup.

Motor
-eagle forged 6.125 pro series rods
-keith black forged 9:1 compression pistons
-speed pro plasma moly rings
-manley pro series forged 4340 4.00 stroker crank
-custom hydraulic roller cam 226 229 dur@.50 578 lift and 114 ls
-LQ4 heads with beehive comp cam springs
-shaft mounted rocker arms
-63 lb injectors
-Vortech V2 supercharger with stage 2 impeller and air to air intercooler

Tranny
-built 4l60E
-stage 2 shift kit
-no stall
-corvette servos
-kevlar bands

the plan for exhaust is some pacesetters or something with a 1 3/4 primarys and run 3 inch true dual with an x pipe and two 3030 aero turbine mufflers. In the rear Im probabley going to put either a locker or a spool in it, the rear end is toast as well so i have to do it either way. Im looking to get into the 600-650 hp range, fingers crossed. the fuel setup is where I get lost, I had a boost regulated inline fuel pump but dont want to run it anymore. Just wondering what I have to start looking at on the fuel side of things, oviously I need a bigger in pump fuel pump but wondering how much stock fuel rails will handle. Anything Im missing just let me, you help is greatly appreciated.

 

I don't like the cam for what you are doing. Plus, it's going to be tiny in a 408.

You're going to need the exhaust to breath easy, so, I'd look at some 1 7/8 headers and a cam with a healthy exhaust bias -- even more so if you stick with the smaller headers.

With my turbo set up for the 408, a 230/236 .608/.611 cam felt pretty stockish... You might consider a 234/244 (ish) cam with lift specced to match your heads. I'd trade money to the heads and use crane race golds for the rollers.

Forget the 4l60 -- you're going to need an 80 for sure.

Stock fuel rails will be fine for a while -- if you ever switch to a fast or something, then do the rails.

 

+1, agreed on every point, from the cam choice to the 60E. More cam that is exhaust biased and go with an 80E now or you will end up doing it later, after spending the dough on a built 60/65E once or twice. I'd ditch the beehive Comp springs also, seen way too many end up in pieces. I'd go with some quality duals to go along with a cam along the lines of what Erik recommended. I've recently been turned on to the Manley Nextek duals w/o dampeners, as well as their ti retainers.

 

im keeping faith in my 60e behind a nitrous fed 408 lol. time will tell. i agree that the cam sounds too small. atleast get a MS4 IMO. 1 7/8 headers for sure. texas speed has a reasonable priced set that look awesome.

 

I only plan to run around 10-15lbs of boost so what sort of cam and head setup would you guys recommend? as for the tranny Im gunna see how its going to handle it. the guy who built it said it could handle 600hp but thats probabley max. thanks again

 

lol im gonna stop you right there, im running a stock Lq4 and have been through 2 60es, i can tell you there a POS if your gonna run 10-15 pounds a boost do yourself a favour and just get the 80, your 3/4 clutch pack is gonna be fubar'd after about a month of doggin it. think of it like this you dont put a th350 behind a built 454, you get a th400. your in the same boat, 80e FTW

 

You'll destroy your 60e. That's a given. A slightly bigger cam will maximize the engine's potential but the one you have should make torque. I'll be running one close to yours in my 383. From what I've seen, you might want more duration on the exhaust side. The blower packs the air/fuel in tightly so you need more exhaust duration to get it all out once it's burned. I'd run a good stall with a Procharger. I have one for sale if you're interested. I'm going to be running the same crank and rods... we'll see how they hold up.

How much overlap on that cam?

 

I really dont care If i smoke my 60E its easier to pull it than my motor. Like I said before I'm new to this HP game and heads and cam is where I get lost. all that I got for a spec off that cam is 226 229 dur @.50 575 578 lift and 114 ls. most of that is greek to me.

 

For heads, you could get away with stock 317s if you were going to run an NA 408 -- you'd be leaving power on the table, but you could do it. With the FI... I personally would run some AFRs, stage 3 317s, or Edelbrocks from Richard @ WCCH. You want 225s minimum, IMO. What ever you get, though, you need to have flow numbers, so you can figure out the best flow point on the heads. Once you have that, you can target lift for the cam -- you want the cam to hit that sweet spot twice, once on the front side of the cam lobe and once on the back. You do this by taking your max lift number, say its .600 for the heads, and then going a little past that for the cam -- like .605. if you go a lot past it, you lose performance. If you are not high enough with the cam lift, you've wasted money on your heads, and they aren't performing as well as they could be. If you go exactly to the max lift number, then you hit it once and immediately begin backing away, but if you go a little past it, you don't hurt performance at all (they aren't linear) and you with double the amount of time the head is at max flow.

Thing is, with 15 lbs of boost, you're going to hit somewhere in the 700-800hp range -- and with a 408, you're going to see *at least* that much torque, and probably more. That torque is going to destroy the 60E, no matter who built it, or how it was built. You are MUCH better off pulling the tranny now and selling it, and then using the proceeds to put in a junkyard 80E with a shift kit (which will last you a while at that level).

You don't need to worry about torque with a 408 -- you will have plenty of that. I made 700 ft.lbs at 14 psi... with a spark plug wire on fire and shutting down at 5k rpm -- and with a 236/230 114lsa turbo cam. It sounds like a big cam, but the CI will eat a lot of that duration. Like I said, the cam feels pretty stockish. I'd have changed it a long time ago, except the cam isn't super important with a turbo.

With a centrifugal SC, you need to make it as easy as possible to spin it up. That translates to a super efficient, easy-breathing exhaust. Doesn't matter what kind of exhaust you have if you don't have enough split to let the engine exhale. You don't need to worry as much about the intake because you are going to be slamming air and fuel down the throat of the engine

In your cam, the 226 is intake duration -- which means that out of a 360* rotation of the crank, the intake valve will be open 226*. The 229 is you exhaust duration. "Overlap" refers to the amount of rotation that the intake valve and the exhaust valve are open at the same time. Overlap is bad for FI -- the intake tract will have positive pressure in it, so if the exhaust valve and intake valve are open at the same time, you bleed good air and fuel into the exhaust (as long as the exhaust pressure is lower than the intake -- with a turbo, sometimes the exhaust pressure is higher, and you actually bleed exhaust into the intake charge).

Because you are going to have a positive charge in your intake, 2 things are important. 1) keeping the overlap as close to 0 (or negative) as possible, and 2) giving your engine as much time as possible to get rid of the spent charge (i.e. exhaust gas). You want a healthy "exhaust bias" and a wide lsa (which typically means you get low or no overlap).

To get a healthy exhaust bias, you want a forward split cam (i.e. the intake duration is smaller than the exhaust duration). For a cent SC with great exhaust, you want that bias to be 8 to 10 degrees, IMO. With a questionable exhaust, you want more -- 12-13* even.

For the 234/244 I recommended above, you'd want the lsa to be as wide as possible -- 114, 115, 116, etc.

 

just talked to the guy that built the motor and he said any bigger of a cam and it wouldnt be any good for a daily driver which was kind of the plan. What if I dropped the boost to say 8 lbs?