Carb Spacer Testing

I tested many different carb spacers and share the results.

[georgedreisch]

Spacers are another example of people wanting to take a advertising based - word of mouth approach to engine development, rather then realizing each combination is unique, especially, at higher levels, and not wanting to acknowledge the amount of “homework”, you’re providing, to provide guidance, not nonexistent canned answers, here.
Thanks for sharing your hard earned and honest experience.

[musclebone]

I can't wait to see these results. I'm running a 1-inch open spacer on my 496.

[adamrushka]

I had one of those tappered HVH super suckers on a mild 340 with an LD340 intake and make a bunch of changes to the carb. It leaned it out a ton.

I later tried it on a much hotter solid cammed 340 with a victor intake. It gained 10hp at the top end. Made 480hp at 6900rpms.

[cammontreuil]

I've got a stock boss 302 engine. Added a 2 inch four hole spacer.
Improved off idle drivability.
Got lucky.

[keithbarron]

Long, long time ago, when question came up, would make a spacer out of wood, spacers were rare, quick way to validate purchase. Didn't have fancy shapes back then.

[waynep]

If you want to have some fun Eric. If your dyno headers have 3 bolt flanges and are 3" and have pipe after the collectors. Insert a 3"×2" Collector adapter with 10 inches of 2" exhaust tubing on it.. this creates anti reversion after the collector. Lowers the pressure in the collector and primary tubes. The slight reduction thru the tube speeds up the exhaust flow increasing scavenging effect. Any reflections coming back upstream can't go thru the middle of the tube. But can go around it into the tapered area at the collector flange. Warning you must carefully monitor air fuel ratio stepping up the rpms 200 at a time. Cyclone headers made some A/R headers for 440-3 motorhomes. The motorhomes got 33mpg but melted the pistons . They could not release them do to liability issues .
Who knows which reducer diameter and length will work best. Wont be expensive to experiment with. I talked to a neighbor who owned 360 and 410 sprint cars. He loved and understood the idea. But there was no place to put them. Then he showed me the many sets of headers his engine guy had dyno tested the set that made the best power at race rpms had stepped primary tubes. But stepped down. Bigger at the port and smaller at the collector. This sped up the exhaust flow again creating additional scavenging.

[elcaminodraco]

Which spacer would be best for a 350 CID with a 4160 Edlebrock Carb and RPM Air Gap Performer?

[RonaldLewis-pyyt]

I'm using HVH 2" 4 hole spacer on a Air Gap 468 BBC i don't have it running yet but I believe will work for my street build, hope to test it soon at the track, I'll make passes with and with out the spacer but really its to keep my 950 carb cool 😎 😊😊😊

[RonaldLewis-pyyt]

Thank for sharing your knowledge and time, finally providing dyno Spacer Results!! Myths!!😊

[smilsmff]

Yes good to see results again. I recall a 440 big block drag challenger using holley street dominator Ported with Conversion 2 inch spacer for a Dominator 1050, back in the 1990s it was 10.0 car.

[johnnystanley]

Thanks for the tech info Eric really appreciate the hard work and showing the results

[andrewbecker]

Honestly, in my experience mostly on the street with pump gas.The biggest benefit to the spacers I chose to run, is the insulating effect. Keeps corn fuel from boiling. Especially in a Quadrajet equipped big block Chevy with a factory cast iron intake. I've found the 3/4"inch Corvette style spreadbore spacer made from plywood laminate to work the best for a Quadrajet.

[patrickwendling]

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

[Aegis]

I'm more curious about spacers vs no spacer than comparing one spacer to another. Maybe you have another video where you do that.

[bigfan]

Did you do a base test with no spacer ?

[danieldimitri]

Dual planes like large or at least large-ish carburetors. It might not get the most out of the carb but you still get a torque hump of the dual plane and get the most from the manifold. Put the dominator on it. Sometimes single planes like appropriately sized carburetors but sometimes a well built large carburetor doesn't care how big it is, it will mix the fuel just fine. Test it dont over think it.

[marksancken]

I was wanting know if the dimpled spacer really makes 20 hp . there is a video on 408 SBC that made 21 I find it hard to believe. if it came from you I would get one. Im sure you can watch it thanks for all the great testing.

[vertexjeff]

I'm running an NA big block Mopar with dual quad tunnel ram. I saw improved fuel distribution when switching from open spacers to the HVH tapered spacers, according to my spark plugs. No changes in ET at the track, though!

[kitvexed]

one of the most reputable engine builders in the northeast (Larry's Auto Machine) saw my BBC 540ci go from 648hp to 664hp with a 1" spacer.. my circumstance is special though - in order to maintain the stock hood on my 1973 camaro, we had to use a low rise WINTERS intake, which they machined heavily to gain power that any tall intake wouldn't have suffered from.. so just about ANY spacer increasing the plenum was going to grossly increase power in my case..

[goofball]

What is the thickness of each spacer. And what is the surface area of the top vs bottom of each spacer?