L31R Porting Intake

[Missouri Mule K30]

New crate engine, just doing some simple mods since I have to get engine in my commuter truck, 98 K1500. I am doing some simple blending on factory lower intake just for grins since it is already off.

Mostly all I can see is to take off either casting lines at runners, a little blending going into the runners, and at the spider location. Very minor around the outside edge as in reality there seems to be an eighth to quarter inch to really come off. But at what gain with stock cam. Do not want to spend wasted time as if the effort is fruitless why bother.

Some minor port matching can also be done on intake and not hurt flow into heads, as again you do not want to open more than entrance into heads.

What do the Troops think while I continue with search?

 

[big_mike]

There is only minimal work you can do before your wasting your time on a stock lower intake. The entire stock Intake setup is horrible for the most part.

Time would be better spent doing required mods for a intake swap if your trying to maximize the L31. Then your looking at a marine intake with external injectors or aftermarket intake options. Either is pricey.

 

[L31MaxExpress]

Given that the stock system has fuel to make 400 hp the intake ports in the manifold are restrictive. I have ported several of the manifolds and had a noticeable power gain. Nothing with the stock cam though. Both of those engines had LT1/LT4 factory cams in them.

 

[Missouri Mule K30]

Thanks for the information. I keep looking at the exhaust ports on the heads and cant see any big power anyway even with cam, and money put into thin casting heads, larger valves, guide clearance, and porting room. Torque numbers are great for a light duty commuter truck.

400 HP is impressive though if that can be attained, with reliability in mind, and cash outlay. I may take the old L31, break it down and look at the cylinders and see if that block is worth the effort, being low mileage
and the "dude" "rebuilt it", uhha. It did run like a scalded dog, up to 98.

No4 rod bearing spun, heard ticking when I got home from work and decided to investigate and narrow down problem. Pulled the valve covers, rockers good, springs check. Pulled pan, pretty easy, and started pushing rods around and 2 minutes later , yep that's it no4, metal in pan. Pulled cap and well put it back on. Pulled 3 cap and crank looked great and bearing not contaminated yet.

Sad but true, and this is a stock replacement but with a little reliability, and with labor cheap,me I figure that some things can be done without much anguish from the Book keeper. Book keeper says that their are other mules outside to feed. How Very True...

Thanks Again from the guy still building 60's and 70's material. I will never run out in my time.