Dimpled Intake Spacer adds 21+ HP to a 408 Small-block Chevy!

In this episode, we do a quick ring and bore break-in. Then, we started testing and tuning. Over the next few hours, we ran multiple tests and adjustments, jetting and timing, testing two carburetors and trying three different spacer variations. The day's big surprise was a dimpled intake spacer manufactured by Polymer Racing Products (polymerracingp...). To our surprise, after swapping out the Wilson spacer for the Polymer one - and with no additional changes - we added an impressive 21.38 HP and 10 lbs-ft of Tq to the power curve!
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[@TheMajictech]

Drill that spacer for a bunch of wet nitrous nozzles then the spacer adds 300-400 horsepower 😅

[@nick_captain_slow]

Years ago when I learned why a golf ball was dimpled I thought about this, well now I know.

[@Thumper68]

So what do you think the dimples are for on a golf ball?

[@perelandra1580]

Love the Black keys!

[@mannycarinha770]

Great video job super well done 🇺🇸🤘

[@internationaldynoauthority693]

Glad you enjoyed it

[@jeffhopper3526]

Dimples... they're not just cute anymore ;)

[@terryenyart5838]

I've learned you never know what works until you try. Sometimes I guess correctly, but I would rather dyno it and know. I feel that's the best way to learn. Great information.

[@jamesgravel7755]

That small block is healthy

[@JamesMichael-yy3zy]

Great job good numbers ordered my spacer thank you !

[@TheClintmeister]

The way you present your testing is excellent! THX

[@internationaldynoauthority693]

Thank you!

[@ThomasELeClair]

@@internationaldynoauthority693 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,thanks for being factual,,,,,,,,not dramatic like most channels........................................................

[@umakemerandy3669]

Thats pretty wild, I've seen someone dimple an intake and it was basically useless. The dimples in this spacer are much deeper though which may be the ticket to it being useful as the intake was dimpled with a dremel type tool and the spacer looks 3d printed or cast. Solid engine!

[@ThomasELeClair]

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Deeper dimples ,,,sounds like the answer...............................................................................................................

[@terryenyart5838]

I like the look of your dyno. I have a SuperFlow & my only complaint is the price of their parts. Dyno works great otherwise & is well built. Invaluable tool. I don't know why someone would not want all the bugs worked out, & tuned properly before installing the engine.

[@internationaldynoauthority693]

Thank you 😊

[@joeenberg7483]

Excellent video lads, well done 👍 That is one sweet little mill.

[@internationaldynoauthority693]

Thank you! We really enjoyed the day. And that is definitely a seasoned, well put together 350 Chevrolet

[@jaywood1763]

Air velocity vs cfm of carb and the heads drawn ... Engineering basis us bigger runners carb and spacer to the air volume velocity per cubic inch ... Dialing it in precise will get you a solid response and power band curve

[@mongoose60ft42]

Just by the name of his channel, I know what’s up. I subscribed instantly.

[@internationaldynoauthority693]

Thanks very much 👍 Enjoy !!

[@mikecondoluci53]

nice little motor

[@DURRIESVISION]

Try a Holley 1050 sportsman (2 circuit) , go 4 jet sizes down out of the box to start. Have had great results. 2 circuit way better to tune

[@internationaldynoauthority693]

This is a circle track car. I'm pretty sure. They're going to want that extra grunt out of the corner

[@mikef-gi2dg]

I like the way you did this video,l it was super easy to watch and learn. Oh NOOOOOO....that wasn't an LS motor....that was an OBSOLETE GEN 1. OMG hell is definitely going to freeze over now. and you did it with a carburetor OH My we are doomed. Is this engine combination available for sale? Great job!

[@internationaldynoauthority693]

Yes this combination is available for sale Thank you Mike. We appreciate your feedback 😃

[@jaywood1763]

The spacer mistifies the fuel closer to a vapor to burn faster and possibly cleaner with less carbon deposit on the pistons

[@jaywood1763]

Seems like you could do the very same with stainless steel mesh screen under a basic spacer

[@smilsmff]

what is engine specs? is this a 700 hp engine that is choked down by very restrictive intake manifold ? or this is a 600 hp engine that is shown that makes more power with bolt ons

[@internationaldynoauthority693]

This is a circle track engine, with 700 lift. They are not looking for drag racing torque, and maximum all out full build horsepower. Where you're looking for a 10th of a 10th. They are looking for really good grunt out of the corner. And very competitive horsepower. I think with 575 foot pounds of torque and 650 horsepower they're right in the range. They're right in the hunt.

[@tomcrosby6332]

Good video. Thanks.

[@brentmcmahon8188]

Call C&S Specialties in St Charles Mo they build custom carbs and that’s you just let them know what do you have inside motor cam crank bore compression.

[@raymosworld_8062]

Very good too top-notch

[@internationaldynoauthority693]

I think, if this was a competitor who was drag racing. If they were looking for a 10th of a 10th. They would be looking at custom carburetors from a carburetor builder. In this case. You win and lose based on making smart moves on the track. And having a very responsive engine. We were able to tune both carburetors until both carburetors ran. Absolutely as good as they could. Without being custom carburetors And I agree with you. If I went up to a thousand CFM carburetor, from a custom carburetor builder. Builder. Like Dale cubic. I can make more horsepower of this entire setup. However, I think the brand new, holy XP. That they chose. Works extremely well. And pulled very hard. It's going to be all up to the driver now to make the proper decisions on the track

[@internationaldynoauthority693]

We are aware of C&S. Good company. We use all custom Dale cubic carburetors. On our own stuff. For this customer they came in from 12 hours away. They were pretty satisfied, with getting the air fuel perfect. And having a power curve that goes straight up to the moon

[@brentmcmahon8188]

Golf type spacer !

[@larryholey4688]

what part number is that spacer thanks for the awesome video

[@Thumper68]

Dimples cause friction not speed up air. What your doing is making the fuel atomize better from air turbulence. I’m a golf pro and build my own engines my dad is a master mechanic and machinist.

[@waynetessier3058]

Hello i'm curious what compression is really worth? My 10.7 to 1 399ci. pump gas stroker makes 641@6400 and 560 ft lbs.@5700 with a BBC journal solid roller 260/266@.050 and 679/668 on a 110 lsa. To round it out 261cc Brodix 18* C-Series heads(told 404cfm), QFT 950 Black Diamond on a GM Performance 2 piece intake. I'm looking to retire next year back to Windsor Ont. from a little town in NYS that doesn't have e-85 in the area. Do you think it would be worth it power wise to up my compression to 13 or 14 to 1 and run e-85 as it should be readily available in Windsor. What would you think would be a reasonable increase to look for? Not really interested in nitrous, blower or turbo. Will definite look into the spacer, oh and that was an excellent dyno video.

[@internationaldynoauthority693]

Each full point of compression is worth 100 HP. Depending on cylinder heads Depending on fuel Depending on cam Depending on rpm Depending on induction Etc...etc.. "All out" builds 1.8 HP / cubic + can use 16 + compression.

[@waynetessier3058]

@@internationaldynoauthority693 Thank you for taking a moment to address my question, think I want to keep everything I have and keep it to a compression issue along with the intake and carb as it's just a street toy. Doesn't seem it should be much of a stretch to pick up an additional 100 hp. if I go with e-85.

[@internationaldynoauthority693]

@@waynetessier3058 Yes, but you will need a completely different carburetor. If you're going to switch to e85

[@sharons9367]

Interesting seen someone else dyno test this spacer no increase whatsoever over other space that was fitted

[@internationaldynoauthority693]

Yes I agree. 1- On this Engine 2- with this customer's intake 3- with this carburetor 4- with this cubic Inch 5- with this cylinder head Etc.. etc... This spacer proved very responsive. L O T S of testing Should be tried/conducted, and combined and reported to see the effects on different combinations. What video did you watch? What was the title of it? Who conducted it.? Thank you for writing in ...in.... Originally this was Just a tuning session, AFTER the customer added the spacer, and we documented it, and saw the results, we published it.

[@jameshall4906]

Was that a 1 inch spacer from polymer products ? Thanks , excellent video

[@internationaldynoauthority693]

Yes it was .

[@awfulcoffelsonecargarage8215]

That's some really good numbers out of that motor I have a 73,400 I'd like to do something with do you guys build Motors or do you just Dino them

[@rebekahfrench5747]

Air filter will change that fuel setting too.. just a spacer alone makes a difference without dimples.. like to see comparison with and without dimples i bet there be negligible difference..

[@marcchartrand8614]

The Wilson that was run just before the dimpled one was un-dimpled. The 21+ HP was made with head-to-head parameters - dimpled vs undimpled.

[@internationaldynoauthority693]

Agreed, I think what we will do. Is one day. We will take one of our modified motors. And do a whole barrage of just testing. In this case. We were tuning this particular engine so that the customer was ready for circle track season. But, it would be interesting to take that exact same spacer have the dimples removed. Or manufacture one with no dimples. And see what the difference is. Then it would be nice to stack two of them. Then it would be nice to try a 2-in. It would be nice to try one of those underneath of a straight 1 in. They'll be a lot of fun testing all of those combinations for sure. One thing for certain. When we added this particular spacer on this particular day to this particular motor. It definitely was a very good combination. And the results were very favorable for that customer

[@rebekahfrench5747]

@@internationaldynoauthority693 thats the best honest results... carry on we love big gains over hyped up expensive junk..

[@CherezianRacing]

Could any of the hp increase be from going to a 1" spacer from a 2" spacer? Maybe the plenum volume is already too large in the intake.

[@internationaldynoauthority693]

Totally possible, would require looking into, for sure

[@awfulcoffelsonecargarage8215]

Is that a dark block or GM block

[@awfulcoffelsonecargarage8215]

I'm sorry Dart

[@internationaldynoauthority693]

@@awfulcoffelsonecargarage8215 yes. GM perf. Block You

[@MrMechanicandy]

Wonder how it would do on 350 horse vortex motor with better head and a eldebrock vitor manifold ?

[@internationaldynoauthority693]

Inexpensive way to find out....

[@internationaldynoauthority693]

polymerracingproducts.com

[@tracylewisperformance2270]

Any surface that air flows over we dimple. Throttle bodies to intake manifolds.

[@DangrsDave]

I'm surprised that spacer worked that well. Now I've seen head ports dimpled and heard that it doesn't work. What are your thoughts on dimpling the ports in the head?

[@internationaldynoauthority693]

As always, I think you need to test and to try. That is a big test. If you're going to dimple the entire intake tract on the cylinder head. It's going to take some time. And you're going to have to test it back to back. However. It would be an interesting test. This seem to work very well. But, I'm not completely certain any more dimpling is necessary. And I think that different combinations will work with this and probably other ones will not favor this as much. Test test test test

[@tracylewisperformance2270]

In every case we have tested we see gains in dimpling. Rottler has a patented CNC program for their 5 axis machine that does these and they have documented before and after examples as well.

[@stevenbelue5496]

Was that on the flow bench or the dyno? It may not show gains on the flow bench but the extra atomization could surely show improvement on the dyno.

[@roberthirshfield3571]

I’m wondering if this works only on hi out put engines or will it increase hp on a slightly modified engine

[@internationaldynoauthority693]

I think, a lot of testing is required..... Stay tuned for testing coming up --!!

[@josephdavis6198]

What would it do on Super stock 408 Q-jet carb

[@internationaldynoauthority693]

The results are going to be fairly similar, on pretty much each setup. Setup. Each setup, depending on the camshaft, depending on the RPM range, depending on the carburetor and the spacer and the intake are going to vary. However. You are taking air that is going to travel from point A to point b. You are forcing that air to travel more distance to get to the same destination. This has the effect of speeding the air, and, while it is the same volume. AirSpeed is everything

[@asylumville8544]

I'm splitting hairs but I'm curious if it's the dimples or simply the different spacer geometry.

[@internationaldynoauthority693]

That would be an absolutely great test to do and I totally agree. I think that to do just basic testing. We would have to try a whole bunch of different spacers and spacers with dimples and spacers without dimples and, all different heights and all different styles. And actually do a spacer shootout. However. It would only be valid for that particular engine because every other engine might not work. The same might work the same. That's why when this actually actually worked on this motor. At this time I was impressed. And, I did not say all the spacer is the best thing since sliced bread. Because, who knows. I think you're absolutely right you need to do a lot of testing and stay tuned for our upcoming series because we are going to do a lot of testing on a very modern platform. With a carburetor and a bunch of spacers

[@95bravoforlife75]

Currently building a long rod 408 for my Gasser street strip. I am setting it up for E85. I'd be curious how that one would run on E85

[@internationaldynoauthority693]

Certainly a great experiment to try. And, a great way to do that is purchase a very inexpensive part that no matter what cannot hurt. Might even make you some more power. Let me know how it works out. Or if you want some Dyno time

[@josephverdone7099]

As you changed valve lash. Where were you at your first setting and what did you change to setting.

[@internationaldynoauthority693]

,.010

[@internationaldynoauthority693]

We checked lash. Set at 10 thousandths after break in . We then verified that each was still at ten thousandths

[@josephverdone7099]

My 409 is set at a bit loose at .022hot.

[@sleeeper88]

Cam specs on this?

[@dm-hg1tf]

Which intake manifold is being used?

[@internationaldynoauthority693]

Edelbrock Victor Single Plane... Custom ported

[@brentbeiler7051]

Didn’t catch was it a dual plane or single plane manifold.

[@internationaldynoauthority693]

Single plane

[@awfulcoffelsonecargarage8215]

Or the runners on the on the heads

[@brianholcomb6499]

It would probably make more with a 4150 1000cfm, or a dominator! I’ve never seen a 408 lose with a bigger carburetor! Also those usually take more timing! You should probably show the plugs also! AFR readings can be off! Plug tells you everything! 1.64 per cube is pretty good, but I’m betting there’s more in it! 👍🏻👍🏻👍🏻👍🏻

[@internationaldynoauthority693]

Totally agree with you. If I was doing a dyno contest. What I would do, is keep going up and see if them. Until, it didn't make any more power. Tuning for grunt out of the corner. And the best RPM and horsepower down the straight away. It's a circle track car. So it needs that grunt every time. But, I have to say as far as peak horsepower goes, I agree with you. It would be nice to try

[@josephverdone7099]

What brand sparkplug are you running and gap.

[@internationaldynoauthority693]

ngk .030

[@josephverdone7099]

I run NGK R5671A-8 or AR 3924 autolite at 32

[@dougstringer1097]

What is the intake? Open or duel plain?

[@internationaldynoauthority693]

This engine pulls, and makes power, well into the 7000 RPM range It is a single plane A dual plane, will shut down anything after 5,600 RPM

[@dougstringer1097]

Didn't edabrok make a duel plain. Called rpm air gap. That would pull 6500?

[@internationaldynoauthority693]

@@dougstringer1097 Air gap Rolls torque over Starting at 4,800 rpm

[@garycardwell6854]

Great power. What are the camshaft specs?

[@internationaldynoauthority693]

236 241 687 691 111

[@PatandDoopypoopy]

​@internationaldynoauthority693 the excellent way it carries past peak hp, I'd of bet $$ the cam LSA was at minimum 112 and felt probably 114.

[@sleeeper88]

No way the duration is that short with that much lift! These circle engines usually have a 108 lobe sep. Those are wrong specs. It would albe impossible for this engine e to make that power with that duration

[@awfulcoffelsonecargarage8215]

Do you dimple the intake also

[@ThomasELeClair]

,,,,,,,,,,,,,,,,,,how bout this,,,,,,,now dimple the intake plenum to the runners.......

[@internationaldynoauthority693]

@@ThomasELeClair while that might, or it might not work. It's something that somebody would need to try. And see whether it actually makes a difference. It definitely would be worth looking at. However, if it were a viable procedure and if it made power. The grates would already be doing it. The great John causey would be doing this already. Matt from mbe. Would already be doing this since his entire business is doing intakes and intake runners and intake ports for some of the biggest most powerful engines in the world. Steve Morris would be doing this. I think on some very small ports. On some very small engines that are naturally aspirated like a little Honda b16. That putting a whole bunch of little dots, at low RPM probably does something.

[@internationaldynoauthority693]

@@ThomasELeClair ,,,,,,,,,,

[@internationaldynoauthority693]

@@ThomasELeClair ,,,,,,,,, ,,,,,,,,,,,,,,,,,

[@wynettepatton6650]

That’s a stout 408 for only having a 210cc head on it.

[@internationaldynoauthority693]

Nothing "stock" on this. Heads reworked over a number of years.... Stout piece for sure

[@megasharkz1r]

AF number means nothing its just a number try not to let that hold you back "read the plugs".

[@jackline1255]

How do I tune my SBC the correct way? EGT?

[@internationaldynoauthority693]

We pulled the plugs. We cut the plugs. We read the plugs. At several intervals. What reading is fantastic. Plugged reading is fantastic. However, it only shows you the fuel at one spot in the range. When we're reading AFR we are reading 100 over 100 all the way through in the entire range. And we are watching each one of the circuits of the carburetor as they interact with each other as they interact with vacuum. And. If you had a really close look while we were running. We were also recording vacuum. So we could see when the carburetor was acting as a restriction. And we could see when the carburetor was at zero vacuum at full open throttle.

[@internationaldynoauthority693]

We would read the plugs in the '70s. We didn't have an air fuel gauge with the current technology back then. We would also read the plugs in the '80s and even into the '90s. Now that we have technology, I don't think we're going to go backwards anytime soon, but we always always read the plug to verify ignition timing. We read the plug to verify how far it's burning down in cycle. And we also read the plug to see if we're getting a nibble and or if we have a nice brown strap coming up from the bottom of the ceramic

[@internationaldynoauthority693]

Keep in mind, every time We read the air fuel ratio. And we made a change to bring the air fuel ratio into the correct 12.8 range. The engine made more power and more power and more power. When we used to read the spark plugs. It was harder to see. It was more difficult. And you definitely could not jet the carburetor in the low or the mid-range based off of a spark plug. The spark plug only shows you one spot in the range. That's the final and that is the higher RPM with the most heat.

[@internationaldynoauthority693]

Ask Byron.....

[@patrickwendling6759]

Thank you for your knowledge and video's USA 🇺🇸 USA TRUMP

[@internationaldynoauthority693]

It looks as though we might be safe from sharks.

[@mrbizmarky1]

Hvh spacers are the original (outlawed by nascar) everybody’s trying to copy there original design.

[@billzussman5277]

All is well, until i realise these are 3d printed, hard pass

[@internationaldynoauthority693]

@@billzussman5277 When a product works, it works. On this combination, with this intake, cam, comp ratio...etc... etc.. works well.

[@internationaldynoauthority693]

@@billzussman5277 One other quick thing, that we would point out. Is that this video was not? I repeat not about a spacer. Nor was it a commercial for a spacer. It happened, that while we were filming, and while while we were testing. And while we were tuning. Tuning. The customer brought this spacer forward. We took it off another engine. And tried it on this engine. In this case on this engine with this compression ratio with this piston with this intake with this carburetor with this cubic inch, it worked extremely well. So, it doesn't matter where it comes from. Whether it's manufactured by a press, a lathe, a mold, or 3D printed. In this case, it works very well on this motor. Again, this is not an endorsement of this product. This is simply fact-based. You cannot deny that this worked on this particular engine very well on this particular day with this particular setup. My questioning would come down to try it on many, many different engines. Many different styles, to see what kind of difference. Yay or nay that you might have, on those engines.

[@user-zu2ed6ye5w]

I really doubt these claims, because, look at the facial expression on the young dyno mans face as you are blowing about this miracle spacer !! It says you are full of bull !!

[@internationaldynoauthority693]

Here's the issue, we were not there to test the spacer We were there to tune. Look up the business. This is what we do. We tune. We only tune to make the most power out of each engine each time. Yes, we were impressed that this particular change, resulted in a very nice increase. However. The proof is irrefutable on this engine at this time with this cam with the set of cylinder heads with this carburetor, on this combination, it makes a very, very big difference. It runs better. It fuels better, it absolutely makes a boatload of power. For this particular combination. We are no way associated with the people who make the spacer. We outright purchased the spacer. Actually the person who was dyno testing their own motor. Purchased the spacer. And they were only trying it to see if it did anything. At all. The dyno operator had no expectations. And at no point did we know anything about this until we actually tested it. And yes on this day it was very very very impressive. And it worked very well and it made big big big power. Huge power

[@internationaldynoauthority693]

We invite you, to come down. To the dyno. And try your own combination of parts. We invite you to try any combination of spacers that you like. We invite you, to test and tune for yourself. That way you can see whether, it was or was not useful for you on your combination on your engine with your camshaft with your cylinder heads with your intake with your carburetor. And the young man. Thank you very much. He's older than you are