E85 500 HP 383 under L31 truck intake

[Fast355]

Time for a science experiment....Putting a heavily ported L31 base and a 48 lb/hr spider on my L31 based 11:1 aluminum head 383. Goal is 500 hp while staying truly emissions legal with functioning EGR. Will be keeping the factory airbox into the 4" air intake and 100mm MAF and transitioning down to the factory 3.5" opening on the throttle body bonnet side of the MAF. Emissions legal thorley tri-y headers and high flow cats will remain in place. Keeping the big Lunati bootlegger cam and 1.7 rockers because it idles dead smooth with the Rhoads V-Max lifters. I am also pulling the coil per cylinder setup for now and going back to my Davis Unified ignition coil and module and a set of 8.2mm Taylor wires. My goal is 500 hp crank or 400 hp at the tires with the "factory" L31 injection setup. Mainly because the LS swappers say it cannot be done. If I can find a 4L80E trans segment for the same operating system as the 2005 mexican 5.7 Vortec Green/Blue PCM file I have I will be running an 05 Van PCM with true flex fuel capability using a cheap 3.6 Impala flex fuel sensor.

This engine will basically look like a stock L31 with new intake hoses, headers, upgraded ignition, and perimeter bolt valve cover swap. I want the dyno operator scratching his head trying to figure out how a naturally aspirated vortec 350 truck engine just put down cammed 6.0L power.

[dave w]

Interesting project and goal. I wish you the best.

Historically, 383 have been proven 500 Horsepower Platforms: https://www.hotrod.com/articles/hrdp...vy-383-engine/

dave w

[bubba2533]

Nice! Love when people do different things. Hope you post your results

[Fast355]

Nice! Love when people do different things. Hope you post your results

I definately will.

Talked with Meziere yesterday and it is getting a custom built electric water pump. Its an older model they made for the TPI and TBI engines that has an idler for the serpentine belt built into it. My whole cooling system should have less than 1hp demand on the alternator at peak draw. I am using a 34x19 3 core radiator and a matching aluminim fan shroud with 2 of the 3000 cfm Flex-A-Lite flex wave 3,000 cfm fans.

[Fast355]

Radiator and trans cooler as well as fan shroud have arrived. I have red silicone hoses ordered with matching silicone clamps for every inch of coolant hose on this thing.

I pulled the engine last week, set it on the stand and cleaned the little bit of dirt and grime it accumulated in the past year with some simple green and a soft brush. I pulled the heads off it last weekend and had my buddy that works at a machine shop cut the seats for some 2.05"/1.60 standard length valves I had laying around. The low-mid lift flow numbers had a substantial increase. Up to 10-15#s in some places. Goes to show just how good Lloyd's porting job was on them. I scratched one of the deck surfaces pretty badly on a dowl pin when I removed the head as it was being stubborn. The heads were surfaced another 0.020". They have had 0.040" cut off of them total. Deck surface is still very thick. We had to mill the manifold to match since the block was cut too. I am ditching the heavy wide body 7/16" stud 1.7 roller rockers and going with a lighter 3/8" stud 1.7 narrow body. Since I removed the big 232/244 @ .050 cam I still have plenty of retainer to seal clearance with the shorter valves. I swapped to a double spring set that makes a little more seat pressure (150 lbs) at the new installed height and has 375 lbs open pressure at 0.578". I am going back to centerbolt valve covers. I pulled the oil pan, the harmonic balancer, camshaft and the reluctor wheel. Pulled a few of the rod and main caps just to look. The coated king bearings look new including the cam bearings. The bores look new. Penzoil Platinum 10w30 seems to be as good of not better than Mobil One. I am mirror polishing the tops of the pistons and the combustion chamber to prevent hot spots and detonation. I degreed in the 218/228 cam I had previously in this engine on a 106 ICL. I also trimmed the crank scraper template I had sent to me to match the rotating assembly. I sent the template off to have a custom teflon crank scraper built. 400whp out of this thing or bust. The lower intake has been heavily ported. It flows a little over 300 cfm per port with the spider, plenum and stock throttle body installed. I JB welded up the factory o-ring groove for the TB and am going to open the plastic plenum up to match the BBK 80mm throttle body I scored for $25 at a junkyard years ago. I side gapped and indexed all the spark plugs and marked the cylinder for each. AC Delco 42 heat range equivalent with a long 14mm thread and a washer seat to match the heads.

I am painting the engine while it is out. Have to clean the whole thing with acetone when I get it back together. Block and pan are getting painted black. Heads are getting cleared. The lower manifold and plastic plenum are getting painted red. The accessory brackets and motor mounts have been in a simple green bath since last night and will also get painted. I think the brackets will get painted natural aluminim and the motor mounts black rustoleum.

The finished result is starting to look too good to get hidden back in the van. Speaking of which I just detailed the rear half of the interior as well and have a few pieces of wood to sand and refinish as well as some front door panels to rebuild. When I am finished with everything the van has a date with a local body shop. The roof is peeling and the hood was damaged in a hail storm a few years ago. I have a new hood to go onto it and it is getting resprayed. The vinyl stripes are getting removed. This thing is as rust free as they come and after pulling a couple of dents and respraying it should look and perform better than new. I have spent probably close to $10k on this van since 2012 but it is still as good of a vehicle as anything you can go out and spend 50-70K or more to buy new. I also have a set of Velvac wide box van dual glass mirrors to install on this. Finally have a new 5 cylinder upgraded Oreilly's Murray compressor to replace the aftermarket Valeo I put on this back in 2006.

Also forgot to mention, with the new taller radiator and the efans, having to order a flexalite fan mounting kit for a GMT400 truck. Also going to build a custom air box out of fiberglass to hold a 6"x9"cone filter. I am cutting a notch out of the new hood to direct air into the box and sealing the box to the hood with weatherstrip.

[Fast355]

Manifold is ready to go. Still waiting on some other finishing pieces.

Stock intake gasket vs Lloyd Elliots head work vs my intake port work with a couple of pictures showing the stock port dimensions on the intake that was on my 305 on my Tahoe. I knocked the casting flash off the runners and radiused the port entry in the plenum in the 305 but left the ports alone at the manifold to head flange. Not the greatest port shape on a stock 170cc Vortec head much less a 185cc+ runner head or in my case 210cc runner.

I am planning to shoehorn the stock valve covers over 1.7 narrow body self aligning rockers, 3/8" studs and short poly locks. Like the look and function of the stock covers better than the polished cast aluminum taller than stock covers

I really like the black stock valve cover look because it looks like a "What if..." setup to me. Like if GM had offered a performance L31 like they offered the LT4 in place of the LT1. See the red LT4 intake and know you are looking at something special.