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I'm swayed toward natural aspiration and am very grateful for the advice so far.
Looking at an older thread I put up, I was given advice to put an LS2 cam and LS2 intake on a 5.3 to get the power up. I suppose that would come to around 400 with some milling of the 862 heads I have here, and shorty headers from the Texas Performance kit. The 944 has a nice area under the front nose panel for cold air. Unfortunately, I will have to do a 90 bend to get the intake ducted under should I decide stick with the factory hood latch.
You can gain 20rwhp or more with upgrading to a larger cam with a broad powerband over the LS2 cam. Pull the heads... mill them for max compression on the fuel you choose, add a suitable road race cam, Melling oil pump, upgraded timing chain.... straight shot intake (no 90* bends which suck up power) and let it eat. Don't forget the oiling improvements (baffle/trap doors/Accusump/overfill by 1 quart).
I keep reading about the TSP 224R being such a good cam. How is that for a road race application?
How much should I mill the 862s? .030-.040?
GNX, I talked to a guy with an LS2 swap and using a straight intake pipe rather than bending to fit it under the nose panel without cutting the hood latch. He body-clipped the hood at the front corners. I may do this route since I'm opting to replace the stock hood for fiberglass. That alone is a pretty big savings. The image below is just a reference, it's not the same car. However if you notice, that pipe looks kinked to accommodate the stock latch. No bueno.
Can anyone recommend a cheap timing gear and chain option? Also would I need to ditch the Trailblazer front and rear covers for a TSP 224R?
I like the RollMaster billet timing set with the Iwis chain. WS6Store, a vendor here has great prices on this type of stuff.
Are you referring to your front timing cover, and your rear seal cover?
I have opted for an LS9 cam, and will be converting the front timing cover to an LS2. The price on the cam was too good to pass up at $80.
Will check out WS6 store for timing gears. What do I do to get the lower cam gear on the crank off? Is it press fit?
I also found Summit Racing® Engine Rebuild Kits 08-0068 contains flat top pistons from the 4.8! Perhaps I don't have to mill for compression anymore!
EDIT BELOW:
Need the following questions answered as I am looking at WS6 Store now:
1) Will an LS1 engine rebuild gasket kit work for my LM4? My intake is cathedral. Timing cover is not LS1 after LS2 conversion.
2) What is the recommend timing gear set for racing? Double rollers worth it if I'm doing road racing on occasion? Not exactly making a career out of it, but a weekend warrior - here and there.
3) Since I have an LS9 cam now, do I have to change from a 24x and 1x, to 58x and 4x gears??
4) I've opted not to replace the main cap bolts. Stupid for my application?
5) What head bolt design do I have if it's a 2004 LM4 from a Trailblazer?
Last edited by Uranium238; 03-02-2018 at 04:58 PM.
Need some help on main and rod bearings here. Can I use Clevite H-Series (#MS2199H) for stock rods in an LM4? Would these be recommended for road racing, or is it a bit too much?
On a side note I'm still amazed at how clean the bearings look in this motor after it was taken apart. No copper showing, and no hot spots.
I didn't want to go too big as I'm trying not to go past my $2500 cap. I've opted to replace the main and rod bearings just with stock stuff. I've also been told numerous times not to drop money on ARP hardware despite road racing. I will be reusing the main studs/bolts, and getting a new set of stock rod bolts since I'm missing 3 after picking up this motor from the previous owner.
Need some guidance. I just got free LQ9 lifters that only have 60k on them. Can I use these for my road race build as opposed to buying LS7s? I also hear I should get LS2 trays. Remember I will be using an LS9 cam.
Need some guidance. I just got free LQ9 lifters that only have 60k on them. Can I use these for my road race build as opposed to buying LS7s? I also hear I should get LS2 trays. Remember I will be using an LS9 cam.
You road race it? If you're building something for a road racing purpose it seems like spending the 100 bucks to avoid a potential problem it cheap in the long run.
So are LQ9 lifters crappy for the job? I know the history on these lifters and motor. It never went over 3000 rpm. I will be spinning up to 6800 (rev limit based on collective reading).
Last edited by Uranium238; 03-25-2018 at 02:32 AM.
I’m in the same place you are, building a road course capable fun car. I read after I’d already started in on the engine that the best way to build a road car is from the back forward. I wish I’d known that earlier. Realistically I’d have been better off spending money on the cage, suspension, brakes, tires, etc first and then throwing a junkyard engine with an oil pan baffle and running it till it quit on me. What I am discovering is that the engine is not the most important part of a road course car.
Having said that, since I went backwards and I’m already knee deep in a 408 for the thing, I decided to buy new for the internals to make the thing last. What’s another $100 for new lifters when you’re in for $2000 plus on an engine? It’s peace of mind to me. Again though, if I were starting right now I’d build the rest of the car first and run a used complete engine until I was good enough to need the bigger power.
So are LQ9 lifters crappy for the job? I know the history on these lifters and motor. It never went over 3000 rpm. I will be spinning up to 6800 (rev limit based on collective reading).
Theyre not crappy per se, but you're building something that will presumably see extended rpm and WOT sessions. You need a good timing set with a dampener and should start with good lifters and springs.
02-27-2018, 04:45 PM
