picked up a 70k mile LQ4 tonight .. going with a victor jr and a pro systems carb .. sugestions on cam and heads ..plz
For the $ your going to put into a victor jr and good carb, just keep it EFI and run a Edelbrock Pro-Flo XT LS Intake or FAST intake /w a 90mm TB and a conversion wiring harness.
It costs no more to go EFI compared to a good carb setup: (mainly because most good carbs cost $$, then a MSD harness/ignition to run it with a carb, carb intake, etc)...
Best thing you can do to make good power for the $ on a LQ4 in my opinion is the following. It will give you about 525-550 flyweel horsepower very easily to start with:
You're starting with 9.4:1 approx /w -8cc dish piston. So swapping heads fixes the low compression and adds a ton of power.
1) Yank the 317 heads, ebay the complete truck EFI intake setup for $150 buy it now, sell the 317 heads for $225-250 on ebay, sell truck oil pan for $75+ on ebay
2) Order a set of CNC 5.3l heads milled to 59cc (I recommend PRC Stg 2.5 5.3l heads /w double springs-###. retainers) for $1250 new. This will give you about 10.7:1 compression
3) I recommend 11:1 compression on 91 or 93 octane, so order .040 Cometic head gaskets (thinner than the factory MLS .054 thickness). This will give excellent quench and approx 11:1 compression which is no problem on pump gas.
4) Camshaft should be a 23x/24x grind with just over .600 lift. You cant run the biggest stuff with stock pistons (no valve reliefs) without flycutting the pistons. I would recommend a Comp XE-R lobed 238/242. If you go carb, run 111 approx LSA. No reason to run any smaller really unless you want a really mild driver setup. I would run a 224/230 if you are looking for a mild setup..no reason for anything smaller unless you want it to idle like a stock truck.
5) Put in a Melling 10296 Oil Pump when you swap the parts ($140 or so) and a LS2 timing chain ($40). Youll see great oil pressure and no worries with that setup.
6) Stock coils, NGK TR6 plugs with 11:1, TR55's if you run under 10.75 or so on pump gas. MSD wires (best resistance of any ive tested)
7) Swap to a stock Fbody oil pan/windage tray/pickup