fixing the WORST ENGINE DESIGN I've ever encountered

I still don't know why GM designed this intake manifold the way they did, but today, we're gonna fix it permanently, and the right way. When we're done, we should have a bump of about 20 horsepower, and eliminate some problematic issues with the PCV system. However, there's a good chance we might ruin this intake manifold (inadvertently) as part of the process. In the name of power and speed, we're cutting apart a perfectly good intake manifold in hopes of making it even better, but if we can't weld it back together, we'll be out of luck.

my temporary PCV fix on this manifold last year

Check out Raylar for 8.1 parts. he can do the same modify a stock intake or you can purchase the Gen7R intake as well.

[RAWRMotorsports]

Ive seen other ppl preheat cast with a prepo torch to help burn the impurities out b4 welding

[scottg]

I've done a few cut and gut and the easiest way is to chuck it up in the old Bridgeport and whack the bottom off of the entire unit from front to back roughly an inch from all sides. This gives you plenty of room to clean up the ports and plenty of room to weld on a new an improved bottom. I'd fabricate the bottom cover from 3/16 plate which has a 2"drop in the front with a sweeping radius that follows the intake runner and taper it to the back of the unit to smooth out the airflow.

This mod with Stock heads a comp 46-422-9, shorty headers and high flow cats and exhaust, 42lb. injectors and a proper tune, makes 460 HP and 500Tq at the wheels. (4L80E trans)
The stock manifold with all the other modifications would loose about 30 hp-tq and the engine would lay down around 4800. Time and money well spent over the Raylar bucks up unit.

I don't care what anyone says about the Gen IIV, they respond very well to just a few modifications and are pretty much bulletproof. As you will attest to. Great content, always fun to watch another Gen IIV sucker working on this junk.

[madprops]

I'm not a "welder" but maybe back purging with gas on the inside would help. I also saw something about preheating with a torch to warm up the surrounding metal and to burn off any impurities. Love what you do and so glad you moved to colorado. You inspire me and I'm sure many others.

[MrTRAVELER]

Great idea hopefully. I hope it works out. I will however suggest wearing a respirator while grinding aluminum. There is a lot or theories that ingesting aluminum by breathing it or ingesting it by using using aluminum cook wear causing alzheimer's disease. Also I noticed that he was not masked while spray painting. Please don't take it as criticism. just advice from an old man that is blessed with good health after doing this kind if work for 60 plus years. Please take care of your lungs.

[noobFab]

Once you get the truck back together I would love to see a comparison between a stock intake, your modded intake, and the Raylar

[bluecollarhotrods]

What about the other end of the tube? Guessing that it didn't need to be sealed off?

[BBCMONTE]

It’d be cool to see an egt/afr on each cylinder with stock intake compared to the modified one.

[joshuaelizabethfoster]

Glad to see you got around to this. I prefer brazing to welding cast aluminum. Heat guns are way more reliable on heat-sapping metals. Hope you get at least 15 of the maybe 20 horsepower this mod can net.

[ReshardsAutomotiveWorkshop]

You are teaching me what to do before I get started. 😊👍 I'm so glad you are doing this. I have an 8.1 that I am swapping into a square body Chevy.

[philbert]

For being hesitant, it came out beautiful. Certainly it will balance cylinder availability of air and probably spool faster. Solid gold man!

[ASEWorldClassTech]

I can appreciate your determination. Me personally I would of just fabbed up a sheet metal intake manifold.

[DTunedMotorsport]

My first cast repair job went the same way… turning up the “cleaning action” or AC balance ends up putting a lot more heat into the TIG torch. Fried the torch by welding for too long and ended up in the same boat.

Do your welding in smaller spurts if you don’t have water cooling for your TIG setup.

[roaddoglv]

Nothing wrong at all with that weld job.🔥 Looks like with all these big blocks time to buck up a couple of level from the HF stand. The 2x4 is a nice touch, good work around.

[imonaroll]

Harbor freight has a small cutoff wheel. Works great on getting in those small spaces.❤

[CS-oeog]

LT, I know I didn’t examine that weld, but what I saw looked good. Great video.

[brian]

Looking good! Glad to see a busy shop!

[Scandalouspedals]

Man I wish you would wear PPE for your lungs LT. Especially with aluminum dust. Keep up the awsome work

[Bacongrease]

I think this is a pretty common mod on the intake. You got it! TFS has some good videos on doing this type of stuff. Seems like his technique was to bring the junk to the surface using the AC balance. Would be interested to see the street 8.1 motor get forged pistons and rods and head studs eventually

[abnpthfdr]

That was a ballsy move you did there with opening up that intake. I think it will pay out, big time!!! Can't wait to see the ugly truck running again!!!

[mikeo]

Awesome job! I can't wait to see what these changes bring on the dyno!