: Maximum valve lift 04-05 Northstar 4.6

10-08-13, 11:12 AM
Does any one know the maximum valve lift the 04-05 Northstar 4.6 can accept ? I think this is the year piston with the round bump in the center but I don't know if they have notches. Duration and advance are standard L37. I asked Alan at CHRFab but the numbers he sent me seem too good to be true (.442 with 306 degrees seat duration.) Tried to get him to confirm but he doesn't answer my emails anymore. Probably thinks I am just a stroke wasting his time but I am serious about getting cams ground and having him port my heads. It's a shame.Thanks in advance.

10-08-13, 05:31 PM
Why ? ............. but a stand-alone engine management system might be able to take advantage of some cam work ........ The 2000 - 2004 PCM won't adjust to anything. Port cleanup in the FWD sidewinder configuration is a waste of time.

The 2000 - 2003 engines had fly-cuts in the pistons. Later engines went to piston bumps. Overhaul kits for all have bumped pistons. Not sure what happened to the 10.0:1 compression ratio after 2004. There are 2 or 3 different combustion chambers (and minor spark plug locations) in there, too.

Valve lift specs and roller cam follower ratios are in the different year GM service manuals.

What about info in the Fiero and kit car forums for Northstars ?? Find out how to get in touch with AJXTCMAN.

10-10-13, 10:33 AM
I'm not sure what "sidewinder" configuration is. Is this a port design change for 04-05 or are you referring to the drivetrain being FWD?

I have a 2005 Bonneville GXP. It has a NEW L37 crate engine, 32lb injectors, a custom programmed P07 PCM and a host of nickel and dime upgrades. I want to build more power because I happen to like this car. ARE makes a dry sump oil pan. I don't really want or need one as such but it makes so much room under the engine that real headers and pipes will clear with tons of room. If I can actually run .442 valve lift I can have Comp Cams regrind a set of cams with the 9341 and 9342 grind from the Ford 4.6 DOHC. I will have less lift with the 1.68 followers (.441) vs the Ford 1.8 (.473) Which is great for me.

I think these are real, do-able upgrades not pipe dreams. Cost would be more than some other type of build but I would need a car/motor/machine work/all the other parts, just to make some form of SBC clone like everybody else. The Northstar owes nobody any apologies, it's refined, tough and uses air efficiently. It was simply ahead of it's time and/or not used in enough platforms to spark an after market. But it is 2013, almost 2014. We have CNC grinders, computer generated cam profiles and porting strategies, quality hardening processes, durable, reliable technologies for things like dry sump on a street engine. The P07 was a drag when these cars were relatively new, but several companies have been able to program them and I have had two very successful tunes so far. I'm building a totally OBDII happy engine so the Fiero/sandrail route doesn't really help me, they typically run more duration and overlap then I want, because they can. I was 11 when Smokey and the Bandit came out, we gon' do what they say can't be done. LOL.

Also, the intake manifold design, from 1993 and refined into the piece of artwork my 2005 has, is exactly the design used by FAST for their LSx (not LSX) Intakes. At least I won't need to figure out what to do there. It's all good, I just troll the net looking for solutions to my questions and when I think I am armed with all the facts, I'm gonna star buying parts. I like CHRFab but BRE advertises Northstar head porting too. If I should run up against a good solid FAIL for any of my plan, I will just give the idea the heave-ho. Valve lift is one of those issues as I do not intend to take my engine apart to get the pistons
fly cut.

Thanks for responding and Peace !