Hey guys,

Have been sled pulling this year with my 2000 LQ4 and am looking to "budget" build a new motor for next year. I am allowed to run any fuel, but am limited to factory intake manifold, factory OEM heads and factory Cast Iron Truck Exhaust Manifolds.

My plan was to install flat top pistons out of an LQ9 and fly cut the pistons. Then run something similar to a vindicator camshaft and then mill 243 Heads and port and polish to get 14:1 plus compression. Has anyone done something similar to this? Looking for maximum compression that is survivable by OEM heads and budget internals. I plan to spin the motor to 7,000RPM and will have a 4L80E with a Converter behind it.

Any plans or thoughts are appreciated

 

Can do you a turbo? Factory intake and manifolds would work well for that actually.

 

Can you tell us more about the rules? You could run a turbo, pro charger, nitrous etc with your current restrictions.

Even run the truck on straight meth

 

Straight Methanol or Race Fuel are options. Rules will essentially be:
- 526 Cubic Inch Maximum
- Stock OEM Style Cylinder Heads
- Stock Intake Manifold
- Stock Exhaust Manifolds
- Naturally Aspirated

My current plan but am open to ideas:
- Stock Crank
- Bore 4.030
- Forged Rods and Pistons
- 243 Heads, Milled .050"+ (Anyone have experience with maximum mill size)
- Vindicator Camshaft, BTR Valvesprings
- Increase Compression to 13-14:1+ (Anyone have experience with race fuel or meth)
- Looking to make low end power, since exhaust manifolds will limit high RPM breathing
- Looking to stay away from Stroker for now because of cost
- Truck is already running BTR Truck Cam Stage III
- Truck already has 42lb/hr 8.1L Marine Injectors

 

Anyone have any idea which OEM Cast Iron Manifolds flow the best from the whole LS series.

 

you can also acid port the exhaust manifolds, thats an old trick

I believe you just fill it up with hydrochloric acid and let it eat for a couple hours, repeat 2 or 3 times IIRC

 

That sounds like a pretty good tip actually, open them up a little bit. Not sure how much RPM and how much lift I'll be support through stock truck intake manifold and stock exhaust manifolds

 

Yes, That is a good tip and was used commonly back in the days.

 

What about a stock 87mm truck manifold with a 2007+ cover. Could you get away with that?

The exhaust manifolds will definitely need some work to help flow. They're good as stock manifolds go, but not that good. A stock manifold with increased exhaust pressure can really screw with the cams we commonly spec for a truck with headers. You wont get nearly the scavenging, and frankly sometimes even the opposite as an intake valve opens to increased cylinder and exhaust pressure, essentially disrupting the initial intake flow.

 

How much money you want to sink into this? You could make 1000hp without trying with those restrictions on race gas or meth.