We Find BIG Power! 1969 L88 Corvette 427 Gets Some Wintertime Upgrades! Stock Appearing 700+ RWHP!

Winter time is here, were not like most people. The offseason is where we work the hardest! We put the black L88 Corvette on the dyno in search for more horsepower, and we found some! 2023 Season will be the fastest the FAST Racing Series has ever been!
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[@TheInsaneShecklador]

Gave my dad his T-shirt on Christmas and he really liked it. Didn't understand all the social media logos at the bottom until I explained them. He's almost 80 now.

[@HorsepowerDepot]

That is awesome! Glad he liked it!

[@mattgbarr]

Without a doubt, this Corvette has the best-sounding sidepipe exhaust I've ever heard. My '69 Corvette has the factory sidepipes and they absolutely kill horsepower. Whilst my car will never be fast like yours, I've loved learning what can be done to make it better without getting away from the factory look. Thanks for the upload!

[@craigdickerson7636]

I can watch that vets front end jump all day LOL good luck this season

[@jessegriffin8457]

Keep the vids coming enjoying the hell out of them 😉😉

[@doorkicker8507]

Nothing says Awesome like a stock appearing Vette. Hooking and lifting the front end up. On bi ply tires.👍

[@edwinfeldman8231]

NO, YOU guys killed it!! Need more merch and FAST to come to the deep south.

[@zone47]

I wish I could weld as crappilly as you do. It's amazing that L88 runs up to nearly 8,000 rpm, the factory capped the max power pretty low, like around 5500 as I remember it. 69 was one of the best styled C3s IMO. Good luck for 2023, I can't wait to see the 67 when it's done.

[@HorsepowerDepot]

My mig welding is rough lol. The factory L88 cam runs very very well. We’ve been 10.60’s in a stock 427 with a factory L88 cam. With the spring pressure rule we can’t run it past about 7100.

[@danmyers9372]

I believe the Vette is L88 in name only. I think it runs the same (or similar) 582 ci engine as the orange ZL1 Camaro.

[@keithphillips6111]

I love that black vette but I can't wait to see what you guys do with the 67.....I'm totally in love with the new one!!!!

[@joethompson-tv1ss]

Thanks for your quick response to Zone47. I was wondering if the L88 stock cam was that lumpy. (thought maybe it was after market) Now I know. Appreciate the good content of your videos and explanations of what is going on so everyone understands. Best of luck in 23!

[@HorsepowerDepot]

The stock L88 cam sounds very rowdy. The cam in the black L88 is a custom ground camshaft though.

[@danmyers9372]

Old vs modern cam profiles. Big difference.

[@jamessharp9790]

Merry Christmas and happy new year for best wishes in 23’ . My knee replacement is postponed so I’m getting bikes ready for 23’ , son said he’ll race next year. Thank you for content . Blessings always

[@robertjewsbury3212]

Still blows my mind a BBC running through exhaust manifolds puts down 727 @7300 ‘at the wheels’ D U D E ‼️

[@richardsmith-qy6vl]

Looking forward to 2023 you guy make me proud to be a 427 owner....lol I just bought a new cam yesterday going from hydraulic roller to solid roller about 40 more degrees of lift and more duration. I'm thinking it's going to make a Lil more power hoping to Crack that 700 mark thanks for the video Rick 427

[@PCgonerogue820]

Factory side pipes where about 2 1/4 in. Inside Dia , my friend had put 2 1/2in. custom mufflers (stock length) that will fit under the factory side pipe cover. I don't remember the brand ,but the in inside had big cut (look like big mountains) in the inside. The first set of custom mufflers (had a lot of small mountains inside) where real loud on a 502/502 (the first version that you had to build) , both sets looked similar from the outside but different in the inside.

[@bengagnon6947]

What a car. That L88 engine from 67-69 are my dream cars Jesus I love it!!!

[@willreichert6973]

I just wanted to say happy new year. N much success in 2023 I finally get back to work this January. I will be buying merch. That vett rocks thanks again you guys rock

[@richardpenner4686]

Always enjoy your channel...love your cars..they are real street cars...

[@jimrains8314]

Thought for sure it was going to fly off the dyno. Good job on the pipes. I'm curious do you guys use the traction bar designed for Corvettes or did you build your own? Thank you for taking us along, the stuff you guys call stupid stuff I can only dream about doing. If I knew half of what you guys I'd be proud. We had a saying in the Marines, "Get your head and ass wired together." You are there now and doing great. Best of luck next season and again thanks for taking us along.

[@vrm86gt]

Really enjoy the channel, looking forward to more in 2023!

[@PCgonerogue820]

My friend had to stick boiler gasket material between the covers and mufflers, the outside diameter out the mufflers where 3" or 3.5"

[@shoominati23]

You should try the Flowmaster Pro Series Laminar flow header mufflers, also Beyea and Burns Stainless make some great ones to unlock that last bit of HP

[@josephfriedling9190]

Happy New Year Jordan - thanks for the videos!

[@dondotterer24]

Thanks for the great videos. From Payne Ohio.

[@larrygilkerson4525]

Love your videos. Love corvettes and camaros. Especially those L-88s. Hope to see more of that '67 too.

[@jonerlenbush]

I have a question about the mount you use for your race videos. What is it? It’s awesome.

[@silverbell800]

Would be cool to see how much it could make with a single plane and open headers with extensions once that particular engine or car gets retired

[@dougderby9454]

Anything I build exhaust wise have coated. Turbo stuff. The company uses piston coat. Roughly 2200-2400 range. Never had it come off. NA stuff they coat ceramachrome. Good for 1400-1500.

[@HorsepowerDepot]

I need to look into that. I’d like to have these side pipes coated.

[@darrinjones5951]

Looks like that L88 Is going to Fly out in Space Do I see an 8 Second Pass Great Job Guys

[@HorsepowerDepot]

We’re going to try with a couple cars!

[@darrinjones5951]

@@HorsepowerDepot Awesome!

[@acemaster1001]

Looking good guys

[@pameladunn7346]

i believe the closer you get the muffler to the engine the quitter it will be .... maybe put the large one as close to the front and the other one behind ... also i believe you can get reproduction exhaust tips that are rectangle ... with everything moved forward , should leave room for the exhaust tip "what a great car"

[@toddm9501]

1967, 68, 69, and 70 Vettes are the best

[@72mstoney]

VTEC kicked in at 6500 nicely

[@HorsepowerDepot]

It’s go time at 6500!

[@rpturbo]

@@HorsepowerDepot whatever stator you have in that converter is working with whatever pump they used. PTC converter?

[@hans-olofgoransson341]

Since you are moving to sidepipes I assume you will not be able to run a cross-pipe system. Will that restrict the power in any way?

[@thegreenerthemeaner]

Just a thought.....way back when turbocharged Corvairs were around, one trick was to wrap the exhaust inlet to the turbo. The claim was that it sped the air up thus spinning the turbo faster. Just wonder about wrapping the pipe from the manifold to the first muffler would do for sound and power. If it works, your secret is safe with me.

[@rpturbo]

That's because it kept the heat and energy in the pipe, giving a little more energy to spin the turbo.

[@TheInsaneShecklador]

Engine Masters did a test on wrapped headers and showed zero HP gain on the engine dyno.

[@matiasdamian8106]

Dude you just made a dream come true.. I've been thinking how a C2/C3 corvette would sound with a REAL free breathing mufflers and not the ones that came from factory, and you just made it perfect! They look great, SOUNDS PERFECT, even MORE than Side pipes rumble had, and with the original cover, when the car will be on the ground, you wouldn't tell it has different mufflers... At first i thought the mufflers you used were like "cherry bomb" style, but fortulately they're not, it sounds so nice, no farty sound when let off the throttle, nothing... perfect deep rumble sound. So are they just straight through 2,5" mufflers? the one at the end is a little bigger in diameter than the first one but i assume they are the same design just smaller, right? What a video man... i'm so happy to see this type of things... keep doing this stuff bro!!

[@HorsepowerDepot]

So it has dynomax bullet mufflers and stainless bros muffler’s. Both pretty much the same design as a cherry bomb “glass pack” muffler. With just one muffler on each side it was too loud.

[@matiasdamian8106]

@@HorsepowerDepot Exactly, with only one muffler on each side was too loud.. and both the dynomax and the SB muffler are 2,5" inlet/outlet?

[@HorsepowerDepot]

Yes 2 1/2 inlet and outlet.

[@matiasdamian8106]

@@HorsepowerDepot Nice, i think is the 23.25 in model right? Sorry for bothering, I just wanna know your opinon, would a 3" inch instead of the 2.5" exhaust it has, be too big for this setup? Btw, Thanks for your kindness answering all the comments, really appreciate it.

[@dgiorgi1725]

A VIDEO FINALLY and of one of my favorites too, the L88. What is the diameter of the exhaust pipes? Impressive HP. Thanks for the video.

[@smilsmff]

2.5 was the limit

[@dgiorgi1725]

@@smilsmff thanks.

[@jeremymcnicol9585]

Nice looking red C3

[@HorsepowerDepot]

Haha! That’s a customer car.

[@zxtenn]

Quick question regarding your engine, do you run the oval port or rect.? Asking because back then [mid/late 60's] there was so much controversy between the oval and rect. heads. Naturally the engines then weren't even close to what is possible now regarding flow or stroker cubic inches or weren't even dreamed of then. A 427 was a 427. I think the real main advantage was the rect. heads had the 2.19 intakes vs the ovals. I knew a guy who had a 69 Camaro drag car with a 427 L-88, dual quads and naturally internal work, i think he barely got into the 10's, back then impressive

[@musclecarmaniacs9789]

HAPPY NEW YEAR!!!

[@turbomike71]

Looks like you got that black Vette going good now. I saw a Mopar back there, so I know you are OK

[@lencac7952]

Nice job (-:

[@christophercastro3302]

I love the L88

[@dtracy03ss]

Is there a limit to size of tubing? It seems like the Factory size was a bit small?, also do the Turn Downs hurt or change anything. Looks like it's got bunches of Power!

[@HorsepowerDepot]

Limited to 2 1/2 inch. And he’s every bend and turn hurts power.

[@billdedrick1914]

What muffs are these? 2-1/2"? Did you ever dyno a set of Spin tech pro street ,super pro street or shoot out muffs?

[@zxtenn]

80 HP increase on a Camaro over the chambered exhaust? Hard to believe. In 1975 i built a YENKO clone which was a 427/425 with 456 gears and a 4 speed, back then i used 2.5 straight pipe back to old school Corvair turbo mufflers, that was supposed to be the hot set up and quiet over something but the Thrush. What are your engine specs for 700+ HP? Thats sick power

[@HorsepowerDepot]

The video of us picking up that much power is on our KZbin. Engine is 560 cubic inch with a lot of compression.

[@danmyers9372]

Does the black Vette have the same engine as the Camaro? I believe you previously said it was a 582?

[@HorsepowerDepot]

Both are 560 cubic inch.

[@mikelauer6845]

What muffler would you recommend? I am currently running a flow master super 10 . I used vibrant bullet in the past

[@KS-dg5zh]

I notice when it got to around 6,000 ish it went to over 7,600 quick.is that the vacuum secondary coming in?

[@HorsepowerDepot]

It’s got mechanical secondaries. That’s just the camshaft, converter, and timing keeping power out down low.

[@KS-dg5zh]

@@HorsepowerDepot makes sense .bringing the power in like that keeping tires hooked.of course not give specs to the competition. Lol

[@CanadianFarmer]

Sounds good

[@chrisbrown3925]

Another great video, heard hay Leno harassing 60s musclecars on his video, any chance your team could set him straight, show him the true potential of a 60s musclecar?

[@dennisswab6020]

big blocks not like small blocks on exhaust flow

[@dennisswab6020]

i changed in my day to thrush mufflers right behind header of my dick harrell 427 and was like different motor ,big blocks have to breath

[@covenantfinancialministrie1275]

Are you running stock exhaust manifolds? If so, how do get them to breathe better to make that much hp?

[@TheInsaneShecklador]

They have to run stock manifolds for F.A.S.T. class. I can't answer what modifications they have made. Likely a very unique cam to help make up for it too.

[@BEANS-O-MATICtransmissions]

They are ported and extrude honed to the absolute maximum. Still a restriction but they're mandatory for the class

[@HorsepowerDepot]

Honestly, we just learned this, but just port matched exhaust manifolds will make 900 to the flywheel. The extrude honed manifolds didn’t make any more power. But our camshaft and cylinder heads are all designed around running exhaust manifolds.

[@MrRanggong]

@@HorsepowerDepot Thanks for being so transparent with your mods info. It gives me hope that I can coax some more power out of my '69 427 while still keeping it stock appearing.

[@legball121]

What mufflers are you using? Looking to quite down my side pipe car

[@HorsepowerDepot]

It has a dynomax bullet and stainless bros bullet mufflers on it.

[@smilsmff]

Very nice

[@dennisswab6020]

big blocks gotta breathe

[@vrg69]

Cool car

[@philipmazzuca2269]

What are you using the Holley for ? Timing? What distributor do you run?

[@HorsepowerDepot]

Pretty much timing and data logging, it has a Holley dual sync distributor.

[@philipmazzuca2269]

👍🏼

[@xozindustries7451]

Can you make the pipes bigger on that corvette for better flow?

[@HorsepowerDepot]

Wish we could! We are limited to 2.5 exhaust.

[@IpseModus]

Red Corvette in the background...!

[@HorsepowerDepot]

Different customer car than the one were hiding! We have a shop full right now!

[@jjsgarage1966]

What are you hiding in that other garage? Lol 72 vette with maybe 79 wheels.. hard to tell!! Goes by so quick!.. sorry 😆 had to be that guy...

[@HorsepowerDepot]

Lol! No sir!

[@excelerater]

A lot of the power you found old timers already know..Chamber mufflers suck,watching the launch Id say you have a lot of missed ET there too

[@tomstiel7576]

is that the swiss cheese car ?

[@340Demon]

Is that 340 in the background intentional? 😂

[@HorsepowerDepot]

Hahaha! Customer/friends car.

[@340Demon]

I’d love to see some content with it. I’ve got a ‘71 Demon 340 I’m gonna try to squeeze some power out of this winter/spring while looking stock.

[@6or1]

@@340Demon The 71's with Thermoquads are the way to go in the small block class, but 1975 360 Thermoquads are 850 cfm and look the same as the 71 800 cfm unit, as long as you don't check the numbers on the base. Boring and stroking 360 blocks out to 410 inches makes bunches of power and looks just like a 340. No reason to use a valuable 340 block on a stock appearing drag car.

[@derrelcarter9401]

Those are 2.5" pipes

[@dennisswab6020]

quicker out on big block the better

[@jeffcarpenter396]

Is this a 565 cubic inch

[@HorsepowerDepot]

560

[@jeffcarpenter396]

Awsome

[@dennisswab6020]

no headers .........they will help more

[@HorsepowerDepot]

We can’t run headers in the class we race.

[@dennisswab6020]

side pipes too restrictive with mufflers

[@joe-hp4nk]

Customers bring there car to a competitor for improvements, that doesn't make any sense.

[@jorgelozada5582]

6k swap

[@SCRAPPS13AFR]

to quiet sounds like a chicks car

[@HorsepowerDepot]

My mom has one too. So makes sense lol.

[@georgekatsipodas1340]

Another cheque cut to BES engines for more power . Cant do crap yourself. If it wasnt for BES you would be still cutting 14.4’s!

[@kennydemartini2169]

Maybe you should build him an engine.

[@zacharymorris9917]

Haters gotta hate.

[@markwise9868]

What's wrong with paying an expert for their expertise? Very few people have the tools and experience to build an engine at that level.

[@zacharymorris9917]

@@markwise9868 even fewer people realize they lack the expertise.

[@iimikeyb-5159]

If that’s what you think is the only working component on these cars your just plain ignorant

[@tomhanson4153]

Please move your gas cans away from the exhaust from the vette! Away from the dyno period! HAHAHA!!! NO FIRE ZONE!!!

[@gteefxr3094]

🏁🏁👍👍