NOT Your Grandpa’s Big Block! | GM 8.1 Heads Explained | Engine Rehab Episode 8
Vložit
- čas přidán 17. 10. 2023
- This is the most comprehensive 8.1 head video anyone has ever done. Is this going to be the next big thing? LS guys, eat your heart out. These heavy iron lumps make POWER, and do it with easy! Today I go over the differences between every single 8.1 BBC head available on the market today, complete with flow data! Buckle up, this is a long one.
- Auta a dopravní prostředky
We have had two 8.1s and another still in the family. Love every minute with them.
Not sure how I'm just now discovering this content. I've been waiting to see the "all in one" flow chart. Hope to see more 8.1 related content. Thank you Josh's Engine Rehab!
I’m more of a ford guy, but love to learn stuff, so that’s why I watch your channel. It is amazing to me there isn’t that much aftermarket for these. Especially cylinder heads, these engines seem like they have way better architecture then the old school bbc. Just by looking at the intake runners, no long-short runners, dumb design imo. They corrected that, way easier to tune I’d imagine. With the old school it’s seen you’d have to make compromises, unless you have a sfi system.
I used to own an 02 GMC 2500HD with the 8.1 and Allison package; great logging truck! Would own another,but you absolutely want the Allison behind them if you're working with them.
Cant wait to assemble my 8.8 with your ported 8.8 heads!
Me too!! We’ll go make fun of the plebeians with their lowly 6.0’s.
@@EngineRehab I forgot to tell you, I fired up the mostly stock 8.1 at the track to load up the racecar and the guy next to us commented how good it sounds.
I own a avalanche 2500 8.1 and I love it. It hauls all my tools and equipment.
Im so happy rayar supports the platform, but I can’t wait for some competition to improve the breed.
I just finished watching Lawrence Tolman on his 8.1 swap yesterday until I saw his videos I forgot all about the 8.1 engine. The first one I saw was on dirt every day in an Avalanche 2500.
I’ve always loved big block engines whether it’s Ford GM or Chrysler or even Pontiac. you rarely hear about them anymore.
I love the information you’re sharing and well appreciated. If I could I would love to swap one into a 87-91 Chevy caprice classic 4L80 and a 4.10 gear ⚙️ true trac differential. Something mild redline at 5100-5300.
I like your idea of running cast iron manifolds and couldn’t agree more with that.
I did, too. He did a significant revamp on his combo over the last 6 months (cam, intake mods, etc.) and went SLOWER. Not just because he spun at the strip. Just... slower everywhere. I feel his frustration.
My uncle has an 8.1L in his Avalanche. I've been talking about how these engines are slept on for 10 years now. I'd love an aluminum block with a 427 rotating assembly with the Raylar heads and intake and 8.1 CPU. Oddly enough, the 427, 454, and 8.1 all have the same bore
Probably a packaging thing, stroke affects the size less so you wouldn't need to change the mounting pattern for the engine. Also in the applications these motors served, more stroke can provide more much desired torque for towing or otherwise
Amazing video thank you for shedding light on such a awesome and looked over power plant.
Excellent, factual data. Thanks man, good stuff!
I just subscribed, I like the fast editing that keeps the video on topic and efficient.
I am sold on this 8.1 swap for my boat. I have a 350 SBC in it now. I think the 8.1 swap with a self learning EFI will bring my boat into the millennia
Awesome video man. Love it!! I have been a bit afraid to advise running heavy springs in the past cause people use the little stock studs with raylar 8mm nuts. I afraid they going to break off. Thank you for schooling us!
Incredible amount of information thanks for making this video
Subbed because not another stinking LSx/LTx CZcams Church !
Keep those outcasts and misfits engines on the spotlight !
You're doing the hotrod community a service. 👌😊👍
Great video very informative. The problem is the cast pistons in these motors. Stock there are great motor, the upper ring is so close to the valve relief that any excessive heat or pressure over stock seems to persuade the rings to knock off a piece of the piston.
Fantastic info bud!
subscribed because 8.1
and damn good info.
Thanks for sharing!👊😎
Great information. Thanks
Thanks for doing this video
I have an 02 2500hd chevy crew cab 6.0l ,4l80 ,4.10 4x4 and pulled the 6.0 out and swapped in an 8.1 out of an 03 avalanche and love it .
Sub’d! I’ve had 2 8.1s and my 04 Suburban 8.1 is running strong but I’d love to build a “modern” 8.8, basically take advantage of the PSI improvements , quality parts selection and some porting and it sounds like you’ve done exactly that! I imagine 500ish HP with a flat torque curve to tow stuff with, stock reliability and make the big burb boogie. Look forward to seeing more 8.8 content!
680hp/740ft/lbs at the crank
My 8.1 swapped SquareBody crew cab is just about ready to drive. It's been around the parking lot. Still fabricating the exhaust to plug in the O2 sensors to.
I’ve only had 1 LS7 break on me, out of 4 I’ve had I think. After that I beat the hell out of it and never missed a beat
I love this platform!
I plan on using it in a 70 Chevelle with a 4l80
Trust me you will absolutely kill a 4L80 trans behind an 8.1
I hope you are right about aftermarket parts but they only made them for 10 years in less common applications. It’s the reason why there isn’t much out there now. I do agree this engine will continue to be more desired and valuable.
Thinks the first time you drive your burban and press on the gas it’s gonna bring a smile to your face. May be a mere smirk, but a smile to say the least, lol. Look forward to more info on these. Kinda sucks gm didn’t use aluminum for the cylinder heads to cut down on weight. Guess they were more worried about reliability, I’d guess.
I hope so! It’s just a family hauler. If I like it I’ll do all the suspension and I’ve been exploring a 6L90e swap. The truck was originally gonna get one of those, but we never did it and did the 4L80e for ease of install. And I’d say the cast iron heads were more for cost, longevity and tradition. It’s a good design. There’s some dumb stuff but nothing thats not fixable.
They sure didn't care about weight even making steel brackets instead of aluminum.
Nothing light about a gen 7 platform
@@EngineRehabI would absolutely love a 6l90e swap video because there’s not a lot of info online about it because it uses a separate transmission control module
@@EngineRehabdo not go 6l90. They’re all grenadine left and right and cost more than ls3. Stay with your 4l80.
1:53 "Well into the four digit horsepower numbers and broke into the 9's I believe". I checked it out and LT's Ugly Truck makes 817whp, lives in the 11's and ran a 10.9 before he rebuilt the 8.1L. 👍
Yeah I had a few references off. Either way still rad!
Lt totally made like 940hp or so, but being a smart man who actually likes to drive it without having it impounded or stolen. He advertised 800hp or so....while saying he was playing with tuning. My white board with all the figures he gave worked out to 920/950hp, if I remember correctly it was just after he e85 converted it. Really if you had a nearly 1000hp internet famous truck like ugly truck, would you feel safe leaving it outside a store while shopping? If everyone knew it is what it is? His COPO truck, in a way of for instance, had people putting screws in front of his tires at the track. Be smart people.
How the hell LS are so expensive when you can STILL go to the junkyard and pull a 5.3 for 750 is beyond me. You can get really lucky and find an aluminum 6.2 still, for the exact same price, bc the crusher yard doesn't give a fuck.
Definitely depends on the area I suppose. Here the yards charges by popularity of the part. That is f the la didn't throw a rod or break a piston.
@grndragon2443 My local yard only charges for the features. Aluminum blocks cost more because they can get more money for aluminum, so lose more money letting it go.
Yeah true but there’s tons of ppl that wouldn’t know were to begin on pulling a motor let alone the work
theyre only gonna get more expensive now, since GM stopped production and all the tards who throw 15 psi at them and blow 💥 them up 😂. Here in a bout 15 years from now y'all will be back to the remaining supply of gen 1 SBCs, since the LS crowd are too cheap to build a big block 🤣
Just saw the I Do Cars teardown video on one of these and I must say, you're right it's functionally just a high-displacement Iron Block LS. Excited to see what the future holds with these powerplants in street performance
They’re growing! I’m excited to see if I’m gonna hate my suburban or not with the new engine.
What a bunch of junk send it all to me 😁
Good video .
You plan to play with the valve job and bowl anymore on the psi exhaust ?
Low lift flow is always in the seat/valve Area.
Now i have to go out in the shop and do some 8.1 to 8.8 exhaust comparing
Going to work good with my little .538/.542 lift cam
The Raylar heads are the Rolex on the table.
Because they’re spendy?
If you are referencing that old profile made head that was a $3500 head for aluminum not bad back in the day. Those heads Phased out around S/N 750. The newer and Better BB heads now somewhere around S/N 2000 +. Raylar heads are the Rolex of heads for that motor period! Thumbs up for the video!
The PAC 1219X springs were a direct drop in for the stock 8.8 beehives on my heads... and work great with my XM296HR cam. Check out my latest videos of it running. Just need to find an engine dyno here in Atlanta to get some numbers.
This is a rad video!!! I dropped a 8.1 in my 84 c10. I love it so far but when it hits 194° a squeak comes almost sounds like a belt But its not 😅. Any guess what it could be lol. Im hoping something simple not a rebuid lol
I do wish someone would do this exact video with the 80s and 90s big block 454, I know there's aftermarket but not everyone has 5g to get a set, and 70s oval and square ports you can give it up around my area there no where to be found, I know peanut ports suck but knowing the flow data and springs measurements would be nice when putting something together from a pile of parts
I notice the 8.8 has more rotation of the valves,they should have a steep short side by guess.
In the natural gas industry. Those PSI engines were not very popular with Al Gore. A great engine, but not clean burning enough for the government. Sadly most of them got scrapped, or on someone’s last day at their job, ended up in a shade tree project. A decent catalyst helped with the emissions but those were really costly.
I've had 3 of them. With an 80 per cent load and oil cooler they last as well as anything. Big problem is Chinese bought PSI real shit after that
The first 5.3 I bought for my truck 15 years ago was $420 with a lifetime warranty. You can't touch them for that anymore
It would be nice if someone could make an affordable dome piston. Wiseco has a 4032 flat top for $650-700 the cheapest I found. I called around a little bit for some custom pistons and everyone wanted 1,500 dollars.
$650-700 that sounds like a deal.
If I watch all these videos do I get an AA degree in automotive engineering? You are a great teacher although you were a little light on sarcasm today. Enjoyed the “baby” comment.
Yeah I forgot to be sarcastic in this one. Very out of character.
How is the exhaust port spacing on the 8.1 compared to a 5.3 or 6.0 ls? Im curious if i could buy a 6.0 turbo manifold...cut the flange off and weld a 8.1 flange on? Guess ima get some exhaust manifold gaskets and compare.
You can move two Head bolts and bolt a conventional Head on the gen 7block
I went back to good old chevy 350
Time to go cruise marketplace..
Josh I was wondering where you're located I would like to have you do some work on an 8.1 long block
Aluminum RSX heads from Chevy.
I just want to keep my stop engine 8.1 working as a work engine . What. Should I do to keep it running correct.
My eagle230 eliminator (boat) has the. 8.1 in it, thing is a beast…..i believe in the marine industry its called a mag 496
Have a mag and ho
Are the valve angles the same on the PSI 8.8 heads?
😎😎😎
Can u point me the way to a set of 8.8 heads please. I found a 8.8 on ebay but i not sure I can get it to fit my c10 cause of the oil pan. Will a 8.1 oil pan fit the 8.8 also will the 8.1 harness fit the 8.8.
You can buy my whole truck mostly assembled with a built 8.8 and heads for 12k!
I still buy 5.3s for 220.
What are the flow numbers for a stock 8.8l head? Is it similar to the 8.1? Also can you provide a serial number for a gasoline PSI 8.8l engine so i could call and get pricing? Thanks for all the info you've already provided!
Look for used ones. Contact hank slocum on facebook
Can you put a link on where I can get these 8.8 cylinder heads?
What is the stock valve length on the 8.8 head
The 8.8 are now being used in propane bobtail trucks
Thats a good application for them
I have two of these PSI 8.8's and one is being built for my boat to replace the existing 8.1. I'd love to know how much camshaft I can get away with... using a marine (wet) exhaust system. Reversion is a major concern and right now I have a Merc 496HO cam to use. Would love to try the Comp XM296HR in this 8.8 but the 75 degrees of overlap worries me.
What is the best marine cam to use in an otherwise stock 8.8 ? Im running the forged 10:1 flat tops and a fresh set of the PSI iron heads.
Treat it like it’s an 8.1. You’ll love the response! How much speed can you sustain?
@@EngineRehab As much as possible. Was hoping the xm296hr would work with wet exhaust since i already have one of those cams on my workbench. lol The Merc 496HO cam is a safe and conservative cam... and wont have exhaust reversion... but wont make as much power as the xm296hr. I cant modify the wet exhaust so thats my biggest concern,
Where can someone go to get a set of your heads?
Can I just buy some 8.8 heads ready to drop in from you? Or send some raylar heads direct to you for your corrections? lol. This is above my abilities and I doubt any machinists in my area would know anything about any of these heads except to just toss some stuff at them.
You can contact Hank Slocum about it on facebook. The 8.8 heads are out of stock.
Is there a link to where I can a set of your 8.1L heads???
Flow is definitely one of the main things too look at but I don't like the combustion chamber design of that 8.8 head it has no quench pad like the 8.1 head. Id be curious to see a Dyno comparison of 8.1 vs 8.8 because of that.
The 8.8 definitely has a quench pad. It’s just got a different chamber shape. It’s very good at slowing the flame front.
@@EngineRehab I didn't notice at the angle of the pic but the 8.8 head would likely want more timing than the 8.1 head for sure.
The smaller chamber in the PSI heads is a far superior fast-burn style chamber. The valve angles are different also... which will allow more PTV clearance.
@@thatturbotruck I think just the opposite. Smaller fast-burn chamber wants LESS timing.
@@apw30534 you are right a smaller fast burn head will use less timing but the 8.1 head appears to be the smaller chamber fast burn head unless I seen them backwards
i have a built 8.8 gen 7 big block 547cid. i have 3 8.1L and also have a PSI built 8.8L thats in my 02 chevy 3/4 ton
Do you love it?
best platform i have ever used . the power it puts down N/A, most LS need boost to get there. 750HP N/A and mine is built for boost and the plan is to run 15psi shoud be good for 1500hp give or take some @@EngineRehab
@@garagemonsters9305 Can you give some build details ? Cam ? compression ? etc...
@@apw30534 custom ross forged dome top piston 10:5 to 1 compression, raylar extreme aluminum head full roller rockers and lifters , custom .700 lift cam from bullet racing cams. Change the firing order back to the old big block so I can use more cams , I have a dart intake and I have to have some fuel rails custom made . They don't sell shit for this motor so you either have to make it or know someone that can . The block is a new 8.8L psi block with forged 4.5 stroker crank with 6.700 rods it's built for boost but have got that far yet .
And I forgot to mention the Holley dominator ECU and wiring, and I still running the Allison 1000 . Just a old ugly farm truck from Texas 😂
What version of raylar head did you use in this demonstration?
Thats the regular raylar
Do the GM or Raylar heads have the reversion tendency older GM heads have on the exhaust side?
What ever happened to the Dart 8100 stuff?
Yeah I’d say so. The ports tend to get dirtied up on both sides.
And dart destroyed their patterns for all the 8.1 related parts the sold. Only blocks now
They're in my garage. 2.25 x 1.88.
I: 378@0.670 E:245@0.690
on 1 pair of ports
I got lucky and bought a couple castings new in 2018/19 for futures, put in bronze guides and xHD valves, beehives, TS ret. retainers for marine use.
They not light but no worse than others.
@@glennanderson4440 dart heads are identical to raylars. Use them!
Did they ever make aluminum?
The days of noobs buying an LS for $100. Blowing them up weekly and getting a new one while telling old school SBC/BBC people they are idiots for spending money building 50 year old motos is coming to an end.
I like the psi heads myself other than the 8 extra pounds each over 8.1 head 😖
It’s way more than 8 lbs!
Each . When I weighed complete minus rockers I got 82# for 8.1 and 90# for 8.8
Heavy fuggers
@@randysullivan5723 were those assembled weights? These parts are definitely not light haha. I went with the 8.8 everything for my burb and that engine is over 800lbs.
Was factory assembled heads minus rockers on my bathroom scales so close but not scientific.
I'm doing turbo'd 8.8 in my burban as well. With heavy azz allison 6 speed behind it .. just because 🤣
@@randysullivan5723I’m gonna break my second 4L80 with this one. I have the ported heads on mine with a raylar bp205 cam. Those lobes are lazy, can use normal springs on those lol
I feel like the L83s are getting cheap though, they just need a stronger aftermarket for swaps
Like the gen v l83?
@@EngineRehab yes
@@cartermackenzie1135 yeah Thats definitely a totally different animal. I had one. Cool engines. Definitely would be more expensive to swap. Much lighter. Lots of small displacement characteristics. Good potential.
@EngineRehab I think we need to make it really cheap to carb swap them. Like make an arduino based ignition controller or something that makes them more accessible to the masses, like the MSD LS boxes but made with an arduino and open source
@@EngineRehab I also think you can terminator x and run gen 4 stuff on the LTs
Are the cheaper aluminum heads on ebay (under $2000) even close to the raylar?
There are no other aluminum heads
@@EngineRehab Are you still selling the PSI heads? Would just be for a work truck. Manifold studs are all broken off, would probably be the same amount of work to swap heads and might as well upgrade while im at it.
@@EngineRehab What are you selling the reworked PSI heads for?
@@eagle94haslanded contact hank slocum on facebook about it
I have a 8.1 in my C3 Corvette has a Dart intake and carburetor. The Dart intake was custom ported and the dual plane was shaved down. It runs really well I have aftermarket race tech pistons rods custom cam roller rockers etc
Do you have a video of that ..
@@ricardobates7891 yeah I can upload one
anyone know how to contact this guy to do work?
I don’t do work for the public
That's to bad have a one of a kind job would be good content
It's a 800 hp cylinder head fix had a supposed to be machinist port it and it's not right anyway let me know thx love your channel
@@rolfemarquis1017 if you reach out to me on IG I’ll refer you somewhere. I_do_airflow
that 8.8 psi head, I think I know who the person is, who engineered them for PSI, I'd have to call him to confirm that. But I do remember seeing a set of those castings in pre cubed form in his facility where he did production and R&D for another notably large company back in the late 2000s, 2008-2010 I think IIRC. So whoever is claiming to have designed that head is probably full of shit. All of the design cues in the casting, the layout etc, all classic design stuff that guy did. I also know for a fact he did contract with PSI on development " not sure specifically which products". Soo maybe these aren't the final version and maybe other engineers worked on them after, but I am fairly confident in who probably had a significant hand in that 8.8 design. To throw you a bone , the guy who designed those $7000 heads you salvaged, I can't say for certain same guy, but likely ;), the original RHS heads 11* valve angle,were actually designed by ET performance in Walled lake Michigan and manufactured under contract for RHS by ET cylinder head prior to their bankruptcy in the mid 2000's. You'd be surprised how many after market cylinder heads got developed at that company.
Yeah I know who designed them.
Id rather spend my money on a Duramax that'll get Tripple mpg and doesn't require race gas
The duramax also requires triple the maintenance costs annually. So that’s another tradeoff.
you dont put an LS swap in a vehicle. an LS swap is not a thing, its a verb. a verb is an action. its something you do thats why its called a swap. 🤦🏻♂️ get it straight lol.
I'm a Ford guy through and through have been since the 80s n LOVE the new coyote. BUT I LOVE THE gm 8.1 and since the day it came out I have been confused how it hasn't been a hobby breaking star . Even bone stock it's a monster torquer 🎉
Good information......... BUT THE CONSTANT INTERRUPTION IS EXTREMELY IRRITATING, LIKE EVERY 6TH WORD THE VIDEO STOPS , HAD TO SHUT YOU OFF
That sounds like you need to contact your internet service provider. It looks like this is a representative in your region. (209) 462-7800 you’re welcome.
@@EngineRehab Your fault his caps lock is stuck too haha
@@gordocarbo you should google the phone number.
Its a video editing technique trimming the dead space out to make the video as short as reasonably possible. Just listen to the video if the cuts in the video get on your nerves. I'd rather he be better at giving information than video editing. Thumbs up from me.
@@EngineRehab Hahaha
Ive had a chance to drive my 8.1 swapped SquareBody Crew cab. And its fun to drive now. Got a lot of finishing touches left to do still